*TC 3-04.4
Fundamentals of Flight
飛行基礎
JULY 2022
2022 年 7 月
DISTRIBUTION RESTRICTION. Approved for public release; distribution is unlimited. This publication supersedes TC 3-04.4, dated 22 December 2016.
發佈限制。已批准公開發佈；分發不受限制。本出版物取代 2016 年 12 月 22 日的 TC 3-04.4。
Headquarters, Department of the Army
陸軍部總部
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Training Circular No. 3-04.4 | Headquarters Department of the Army Washington, D.C., 05 July 2022 |
Fundamentals of Flight
飛行基礎
Contents
內容
Page Preface xv
頁前言 xv
Chapter 1 Aerodynamics of Flight 1-1
第 1 章 飛行的空氣動力學 1-1
Section I – Physical Laws and Principles of Airflow 1-1
第一節 – 空氣流動的物理法則與原則 1-1
Newton’s Laws of Motion 1-1
牛頓運動定律 1-1
Bernoulli’s Principle of Differential Pressure 1-2
伯努利的差壓原理 1-2
Vectors and Scalars 1-4
向量與標量 1-4
Section II – Flight Mechanics 1-6
第二節 – 飛行力學 1-6
Airfoil Characteristics 1-6
翼型特性 1-6
Airflow and Reactions in the Rotor System 1-8
轉子系統中的氣流與反應 1-8
Rotor Blade Angles 1-10
轉子葉片角度 1-10
Rotor Blade Actions 1-11
轉子葉片動作 1-11
Helicopter Design and Control 1-16
直升機設計與控制 1-16
Section III – In-Flight Forces 1-25
第三節 – 飛行中的力量 1-25
Total Aerodynamic Force 1-25
總空氣動力學力 1-25
Lift and Lift Equation 1-25
升力與升力方程式 1-25
Centrifugal Force and Coning 1-28
離心力與圓錐形 1-28
Torque Reaction and Antitorque Rotor (Tail Rotor) 1-29
扭矩反應與反扭矩旋翼（尾旋翼） 1-29
Balance of Forces 1-31
力量平衡 1-31
Section IV – Hovering 1-32
第四節 – 懸停 1-32
Airflow in Hovering Flight 1-32
懸停飛行中的氣流 1-32
Translating Tendency 1-35
翻譯趨勢 1-35
Section V – Rotor in Translation 1-36
第五節 – 翼輪翻譯 1-36
Airflow in Forward Flight 1-36
前進飛行中的氣流 1-36
Translational Lift 1-40
轉換升力 1-40
Transverse Flow Effect 1-41
橫向流動效應 1-41
Effective Translational Lift 1-42
有效的轉換升力 1-42
Section VI – Maneuvering Flight 1-49
第六節 – 機動飛行 1-49
Section VII – Factors Affecting Performance 1-55
第七節 – 影響性能的因素 1-55
Distribution Restriction: Approved for public release; distribution is unlimited.
發佈限制：已批准公開發佈；分發無限制。
*This publication supersedes TC 3-04.4, dated 22 December 2016.
*本出版物取代 2016 年 12 月 22 日的 TC 3-04.4。
Density Altitude 1-55
密度高度 1-55
High and Low Density Altitude Conditions 1-56
高低密度高度條件 1-56
Performance Charts 1-58
性能圖表 1-58
Hovering Performance 1-58
懸停性能 1-58
Climb Performance 1-58
攀登性能 1-58
Section VIII – Emergencies 1-59
第八節 – 緊急情況 1-59
Settling with Power 1-59
和解與權力 1-59
Dynamic Rollover 1-61
動態翻轉 1-61
Retreating Blade Stall 1-64
退刀失速 1-64
Ground Resonance 1-65
地面共振 1-65
Compressibility Effects 1-66
壓縮性效應 1-66
Chapter 2 Weight, Balance, and Loads 2-1
第二章 重量、平衡與負載 2-1
Section I – Weight 2-1
第一節 – 重量 2-1
Weight Definitions 2-1
重量定義 2-1
Weight Versus Aircraft Performance 2-2
重量與飛機性能 2-2
Section II – Balance 2-2
第二節 – 平衡 2-2
Balance Definitions 2-3
平衡定義 2-3
Principle of Moments 2-5
力矩原理 2-5
Section III – Weight and Balance Calculations 2-5
第三節 – 重量和重心計算 2-5
Weight and Balance Methods 2-6
重量與平衡方法 2-6
Center of Gravity Limits 2-7
重心限制 2-7
Section IV – Loads 2-8
第四節 – 載荷 2-8
Hazardous Materials 2-23
危險材料 2-23
Chapter 3 Rotary-Wing Environmental Flight 3-1
第三章 旋翼環境飛行 3-1
Section I – Cold Weather Operations 3-1
第一節 – 寒冷天氣操作 3-1
Environmental Factors 3-1
環境因素 3-1
Taxiing and Takeoff 3-6
滑行與起飛 3-6
Section II – Desert Operations 3-12
第二節 – 沙漠作戰 3-12
Environmental Factors 3-13
環境因素 3-13
Flying Techniques 3-16
飛行技術 3-16
Section III – Jungle Operations 3-20
第三節 – 叢林作戰 3-20
Environmental Factors 3-20
環境因素 3-20
Flying Techniques 3-22
飛行技術 3-22
Section IV – Mountain Operations 3-24
第四節 – 山地作戰 3-24
Environmental Factors 3-24
環境因素 3-24
Flying Techniques 3-31
飛行技術 3-31
Section V – Overwater Operations 3-44
第五節 – 水上作業 3-44
Environmental Factors 3-44
環境因素 3-44
Flying Techniques 3-45
飛行技術 3-45
Chapter 4 Rotary-Wing Night Flight 4-1
第 4 章 旋翼夜間飛行 4-1
SECTION I – UNAIDED NIGHT FLIGHT 4-1
第一部分 – 無助夜間飛行 4-1
Retinal Blind Spots 4-5
視網膜盲點 4-5
SECTION II – NIGHT VISION SENSORS 4-6
第二節 – 夜視感測器 4-6
Aviator Night Vision Imaging System 4-7
飛行員夜視成像系統 4-7
Visibility Restrictions 4-10
可見性限制 4-10
Principle of Operation 4-11
操作原理 4-11
Minimum Resolvable Temperature 4-11
最小可解析溫度 4-11
Forward Looking Infrared Optimization 4-11
前瞻性紅外優化 4-11
Sources of Thermal Energy 4-17
熱能來源 4-17
SECTION III – THE NIGHT FLIGHT ENVIRONMENT 4-21
第三節 – 夜間飛行環境 4-21
Ambient Light Sources 4-21
環境光源 4-21
Artificial Light Sources 4-23
人工光源 4-23
Weather/Meteorology 4-23
天氣/氣象 4-23
SECTION IV – TERRAIN INTERPRETATION 4-25
第四節 – 地形解釋 4-25
Visual Recognition Cues 4-26
視覺識別提示 4-26
SECTION V – OPERATIONAL CONSIDERATIONS 4-33
第五節 – 操作考量 4-33
Distance Estimation and Depth Perception 4-33
距離估算與深度感知 4-33
Airspeed and Ground Speed Limitations 4-40
空速和地速限制 4-40
Hazards to Night Flight 4-40
夜間飛行的危險 4-40
SECTION VI – NIGHT FLIGHT TECHNIQUES 4-49
第六節 – 夜間飛行技術 4-49
Scanning Techniques 4-49
掃描技術 4-49
Lighting Types and Effects 4-52
照明類型與效果 4-52
Ground lighting aids 4-54
地面照明輔助 4-54
North Atlantic Treaty Organization-T 4-58
北大西洋公約組織-T 4-58
Chapter 5 Rotary-Wing Terrain Flight 5-1
第五章 旋翼地形飛行 5-1
Section I – Terrain Flight Operations 5-1
第一節 – 地形飛行操作 5-1
Mission Planning and Preparation 5-1
任務規劃與準備 5-1
Aviation Mission Planning System 5-2
航空任務規劃系統 5-2
Terrain Flight Limitations 5-2
地形飛行限制 5-2
Terrain Flight Modes 5-2
地形飛行模式 5-2
Selection of Terrain Flight Modes 5-4
選擇地形飛行模式 5-4
Pickup Zone/Landing Zone Selection 5-4
接送區/著陸區選擇 5-4
Route-Planning Considerations 5-6
路徑規劃考量 5-6
Map Selection and Preparation 5-8
地圖選擇與準備 5-8
Charts, Photographs, and Objective Cards 5-11
圖表、照片和客觀卡片 5-11
Route Planning Card Preparation 5-11
路徑規劃卡準備 5-11
Hazards to Terrain Flight 5-14
地形飛行的危險 5-14
Terrain Flight Performance 5-15
地形飛行性能 5-15
Section II-Training 5-16
第二節-訓練 5-16
Command Responsibility 5-17
指揮責任 5-17
Identification of Unit/Individual Needs 5-17
識別單位/個人需求 5-17
Training Considerations 5-17
訓練考量 5-17
Chapter 6 Multi-Aircraft Operations 6-1
第六章 多機操作 6-1
Section I – Formation Flight 6-1
第一部分 – 形成飛行 6-1
Formation Discipline 6-1
編隊紀律 6-1
Crew Responsibilities 6-1
船員責任 6-1
Rendezvous and Join-Up Procedures 6-12
會合與集合程序 6-12
Lost Visual Contact Procedures 6-12
失去視覺接觸程序 6-12
Communication During Formation Flight 6-13
形成飛行期間的通信 6-13
Section II – Formation Types 6-13
第二節 – 形成類型 6-13
Two-Helicopter Team 6-14
兩架直升機小組 6-14
Fixed Formations 6-14
固定陣型 6-14
Maneuvering Formations 6-18
機動編隊 6-18
Section III – Basic Combat Maneuvers 6-22
第三節 – 基本戰鬥機動 6-22
Maneuvering Flight Communications 6-22
操控飛行通訊 6-22
Basic Combat Maneuvers 6-22
基本戰鬥機動 6-22
Section IV – Planning Considerations and Responsibilities 6-28
第四節 – 計劃考量與責任 6-28
Planning Considerations 6-28
規劃考量 6-28
Planning Responsibilities 6-29
規劃責任 6-29
Section V – Wake Turbulence 6-30
第五節 – 醒來湍流 6-30
In-Flight Hazard 6-30
在飛行中的危險 6-30
Vortex Generation 6-30
漩渦生成 6-30
Induced Roll and Counter Control 6-31
誘導滾轉與反制控制 6-31
Operational Problem Areas 6-31
操作問題區域 6-31
Vortex Avoidance Techniques 6-32
漩渦迴避技術 6-32
Chapter 7 Fixed-Wing Aerodynamics and Performance 7-1
第七章 固定翼氣動力學與性能 7-1
Section I – Fixed-Wing Stability 7-1
第一節 – 固定翼穩定性 7-1
Motion Sign Principles 7-1
運動標誌原則 7-1
Dynamic Stability 7-2
動態穩定性 7-2
Lateral Stability 7-11
側向穩定性 7-11
Cross-Effects and Stability 7-13
交叉效應與穩定性 7-13
Section II – High-Lift Devices 7-16
第二節 – 高升力裝置 7-16
Increasing the Coefficient of Lift 7-17
提高升力係數 7-17
Types of High-Lift Devices 7-19
高升力裝置類型 7-19
Section III – Stalls 7-21
第三節 – 攤位 7-21
Aerodynamic Stall 7-22
氣動力失速 7-22
Stall Warning and Stall Warning Devices 7-26
失速警告與失速警告裝置 7-26
Section IV – Maneuvering Flight 7-30
第四節 – 機動飛行 7-30
Aircraft Performance in a Climb or Dive 7-34
飛機在爬升或俯衝中的性能 7-34
Section V – Takeoff and Landing Performance 7-42
第五節 – 起飛和降落性能 7-42
Procedures and Techniques 7-42
程序與技術 7-42
Section VI – Flight Control 7-46
第六節 – 飛行控制 7-46
Control Surface and Operation Theory 7-47
控制面板與操作理論 7-47
Longitudinal Control 7-49
縱向控制 7-49
Directional Control 7-50
方向控制 7-50
Section VII – Multiengine Operations 7-58
第七節 – 多引擎操作 7-58
Twin-Engine Aircraft Performance 7-58
雙引擎飛機性能 7-58
Asymmetric Thrust 7-59
不對稱推力 7-59
Minimum Single-Engine Control Speed 7-60
最小單引擎控制速度 7-60
Single-Engine Climbs 7-62
單引擎爬升 7-62
Single-Engine Level Flight 7-64
單發引擎水平飛行 7-64
Single-Engine Descents 7-64
單引擎下降 7-64
Single-Engine Approach and Landing 7-64
單引擎進場與著陸 7-64
Propeller Feathering 7-65
螺旋槳羽化 7-65
Accelerate-Stop Distance 7-65
加速-停止距離 7-65
Accelerate-Go Distance 7-67
加速-前進距離 7-67
Chapter 8 Fixed-Wing Environmental Flight 8-1
第 8 章 固定翼環境飛行 8-1
Section I – Cold Weather/Icing Operations 8-1
第一節 – 寒冷天氣/結冰操作 8-1
Environmental Factors 8-1
環境因素 8-1
Aircraft Equipment 8-8
飛機設備 8-8
Flying Techniques 8-11
飛行技術 8-11
Section II – Mountain Operations 8-15
第二節 – 山區作業 8-15
Environmental Factors 8-15
環境因素 8-15
Flying Techniques 8-16
飛行技術 8-16
Section III – Overwater Operations 8-17
第三節 – 水上作業 8-17
Oceanographic Terminology 8-17
海洋學術語 8-17
Section IV – Thunderstorm Operations 8-22
第四節 – 雷陣雨操作 8-22
Chapter 9 Fixed-Wing Night Flight 9-1
第 9 章 固定翼夜間飛行 9-1
Section I – Preparation and Preflight 9-1
第一部分 – 準備與起飛前檢查 9-1
Parking Ramp Check 9-2
停車坡道檢查 9-2
Section II – Taxi, Takeoff, and Departure Climb 9-3
第二節 – 出租車、起飛及離場爬升 9-3
Takeoff and Climb 9-3
起飛與爬升 9-3
Section III – Orientation and Navigation 9-4
第三節 – 定向與導航 9-4
Disorientation and Reorientation 9-5
迷失方向與重新定位 9-5
Cross-Country Flights 9-5
跨國航班 9-5
Section IV – Approaches and Landings 9-5
第四節 – 接近與降落 9-5
Approaching Airports 9-6
接近機場 9-6
Glossary ....................................................................................................................... Glossary-1 ACRONYMS AND aBBREVIATIONS .......................................................... Glossary-1 TERMS.......................................................................................................... Glossary-4
詞彙表 ....................................................................................................................... 詞彙表-1 縮寫和簡稱 .......................................................... 詞彙表-1 術語.......................................................................................................... 詞彙表-4
Figures
圖表
Figure 1-1. Aerodynamic lift–explained by Newton’s Law of Motion 1-2
圖 1-1. 空氣動力學升力—由牛頓運動定律解釋 1-2
Figure 1-2. Water flow through a tube 1-2
圖 1-2. 水流經管道 1-2
Figure 1-3. Venturi effect 1-3
圖 1-3. 文丘里效應 1-3
Figure 1-4. Venturi flow 1-3
圖 1-4. 文丘里流 1-3
Figure 1-5. Resultant by parallelogram method 1-4
圖 1-5. 由平行四邊形法得出的結果 1-4
Figure 1-6. Resultant by the polygon method 1-5
圖 1-6. 多邊形法的結果 1-5
Figure 1-7. Resultant by the triangulation method 1-5
圖 1-7. 由三角測量法得出的結果 1-5
Figure 1-8. Force vectors on an airfoil segment 1-6
圖 1-8. 空氣動力翼型段上的力向量 1-6
Figure 1-9. Force vectors on aircraft in flight 1-6
圖 1-9. 飛行中飛機的力向量 1-6
Figure 1-10. Symmetrical airfoil section 1-8
圖 1-10. 對稱翼型截面 1-8
Figure 1-11. Nonsymmetrical (cambered) airfoil section 1-8
圖 1-11. 非對稱（弧形）翼型截面 1-8
Figure 1-14. Induced flow (downwash) 1-10
圖 1-14. 誘導流（下洗） 1-10
Figure 1-15. Resultant relative wind 1-10
圖 1-15. 結果相對風 1-10
Figure 1-16. Angle of incidence and angle of attack 1-11
圖 1-16. 入射角與攻角 1-11
Figure 1-17. Blade rotation and blade speed 1-12
圖 1-17. 刀片旋轉與刀片速度 1-12
Figure 1-18. Feathering 1-12
圖 1-18. 羽化 1-12
Figure 1-19. Flapping in directional flight 1-13
圖 1-19. 方向性飛行中的拍動 1-13
Figure 1-20. Flapping (advancing blade 3 o’clock position) 1-14
圖 1-20. 拍打（前進葉片 3 點鐘位置）1-14
Figure 1-21. Flapping (retreating blade 9-o’clock position) 1-14
圖 1-21. 拍打（後退葉片 9 點鐘位置）1-14
Figure 1-22. Flapping (blade over the aircraft nose) 1-14
圖 1-22. 拍打（葉片在飛機機頭上）1-14
Figure 1-23. Flapping (blade over the aircraft tail) 1-14
圖 1-23. 拍動（機翼在飛機尾部上方）1-14
Figure 1-24. Lead and lag 1-15
圖 1-24. 領先與滯後 1-15
Figure 1-25. Under slung design of semirigid rotor system 1-16
圖 1-25. 懸掛式半剛性轉子系統設計 1-16
Figure 1-26. Gyroscopic precession 1-17
圖 1-26. 陀螺儀進動 1-17
Figure 1-27. Rotor head control systems 1-18
圖 1-27. 轉子頭控制系統 1-18
Figure 1-31. Rotor flapping in response to cyclic input 1-20
圖 1-31. 轉子因循環輸入而擺動 1-20
Figure 1-32. Cyclic feathering 1-21
圖 1-32. 循環羽化 1-21
Figure 1-33. Input servo and pitch-change horn offset 1-21
圖 1-33。輸入伺服和變音喇叭偏移 1-21
Figure 1-34. Cyclic pitch variation–full forward, low pitch 1-22
圖 1-34. 循環變距–全前進，低變距 1-22
Figure 1-35. Fully articulated rotor system 1-23
圖 1-35. 完全關節式轉子系統 1-23
Figure 1-36. Semirigid rotor system 1-23
圖 1-36. 半剛性轉子系統 1-23
Figure 1-37. Effect of tail-low attitude on lateral hover attitude 1-24
圖 1-37. 尾部低姿態對側向懸停姿態的影響 1-24
Figure 1-39. Total aerodynamic force 1-25
圖 1-39. 總空氣動力學力 1-25
Figure 1-40. Forces acting on an airfoil 1-26
圖 1-40. 作用於翼型上的力 1-26
Figure 1-41. Drag and airspeed relationship 1-27
圖 1-41. 拖曳與空速關係 1-27
Figure 1-42. Effects of centrifugal force and lift 1-29
圖 1-42. 離心力和升力的影響 1-29
Figure 1-44. Torque reaction 1-30
圖 1-44. 扭矩反應 1-30
Figure 1-45. Balanced forces; hovering with no wind 1-31
圖 1-45. 平衡力；在無風狀態下懸停 1-31
Figure 1-46. Unbalanced forces causing acceleration 1-31
圖 1-46. 不平衡的力量造成加速度 1-31
Figure 1-47. Balanced forces; steady-state flight 1-32
圖 1-47. 平衡力；穩態飛行 1-32
Figure 1-48. Unbalanced forces causing deceleration 1-32
圖 1-48. 不平衡的力量造成減速 1-32
Figure 1-49. Airflow in hovering flight 1-33
圖 1-49. 懸停飛行中的氣流 1-33
Figure 1-50. In ground effect hover 1-34
圖 1-50. 地面效應懸停 1-34
Figure 1-51. Out of ground effect hover 1-35
圖 1-51. 超出地面效應的懸停 1-35
Figure 1-52. Translating tendency 1-36
圖 1-52. 翻譯傾向 1-36
Figure 1-54. Blade areas in forward flight 1-38
圖 1-54. 前進飛行中的葉片面積 1-38
Figure 1-55. Flapping (advancing blade, 3-o’clock position) 1-39
圖 1-55. 拍打（前進葉片，3 點鐘位置）1-39
Figure 1-56. Flapping (retreating blade, 9-o’clock position) 1-39
圖 1-56. 拍打（後退葉片，9 點鐘位置）1-39
Figure 1-58. Translational lift (1 to 5 knots) 1-41
圖 1-58. 平移升力 (1 到 5 節) 1-41
Figure 1-59. Translational lift (10 to 15 knots) 1-41
圖 1-59. 平移升力 (10 到 15 節) 1-41
Figure 1-60. Transverse flow effect 1-42
圖 1-60. 橫向流動效應 1-42
Figure 1-61. Effective translational lift 1-42
圖 1-61. 有效的平移升力 1-42
Figure 1-62. Blade regions in vertical autorotation descent 1-43
圖 1-62. 垂直自轉下降中的葉片區域 1-43
Figure 1-63. Force vectors in vertical autorotative descent 1-45
圖 1-63. 垂直自轉下降中的力向量 1-45
Figure 1-64. Autorotative regions in forward flight 1-46
圖 1-64. 前進飛行中的自轉區域 1-46
Figure 1-65. Force vectors in level-powered flight at high speed 1-46
圖 1-65. 高速水平飛行中的力向量 1-46
Figure 1-66. Force vectors after power loss–reduced collective 1-47
圖 1-66. 功率損失後的力向量–減少的集體 1-47
Figure 1-67. Force vectors in autorotative steady-state descent 1-47
圖 1-67. 自轉穩態下降中的力向量 1-47
Figure 1-68. Autorotative deceleration 1-48
圖 1-68. 自轉減速 1-48
Figure 1-69. Drag and airspeed relationship 1-49
圖 1-69. 拖曳與空速關係 1-49
Figure 1-70. Counterclockwise blade rotation 1-50
圖 1-70. 逆時針葉片旋轉 1-50
Figure 1-71. Lift to weight 1-53
圖 1-71. 升降至重量 1-53
Figure 1-72. Aft cyclic results 1-54
圖 1-72. 後循環結果 1-54
Figure 1-73. Density altitude computation 1-57
圖 1-73. 密度高度計算 1-57
Figure 1-74. Induced flow velocity during hovering flight 1-59
圖 1-74. 懸停飛行期間的誘導流速 1-59
Figure 1-75. Induced flow velocity before vortex ring state 1-59
圖 1-75. 渦環狀態前的誘導流速 1-59
Figure 1-76. Vortex ring state 1-60
圖 1-76. 渦環狀態 1-60
Figure 1-77. Settling with power region 1-61
圖 1-77。與電力區域 1-61 和解
Figure 1-78. Downslope rolling motion 1-62
圖 1-78. 向下坡滾動運動 1-62
Figure 1-79. Upslope rolling motion 1-63
圖 1-79. 上坡滾動運動 1-63
Figure 1-80. Retreating blade stall (normal hovering lift pattern) 1-64
圖 1-80. 後退葉片失速（正常懸停升力模式）1-64
Figure 1-81. Retreating blade stall (normal cruise lift pattern) 1-64
圖 1-81. 後退葉片失速（正常巡航升力模式）1-64
Figure 1-83. Ground resonance 1-66
圖 1-83. 地面共振 1-66
Figure 1-84. Compressible and incompressible flow comparison 1-68
圖 1-84. 可壓縮流與不可壓縮流比較 1-68
Figure 1-85. Normal shock wave formation 1-69
圖 1-85。正常激波形成 1-69
Figure 2-1. Helicopter station diagram 2-4
圖 2-1. 直升機站圖 2-4
Figure 2-2. Aircraft balance point 2-5
圖 2-2. 飛機平衡點 2-5
Figure 2-3. Locating aircraft center of gravity 2-6
圖 2-3. 定位飛機重心 2-6
Figure 2-4. Fuel moments 2-7
圖 2-4. 燃料時刻 2-7
Figure 2-5. Center of gravity limits chart 2-8
圖 2-5. 重心限制圖 2-8
Figure 2-6. Weight-spreading effect of shoring 2-11
圖 2-6. 支撐的重量擴散效果 2-11
Figure 2-7. Load contact pressure 2-12
圖 2-7. 載荷接觸壓力 2-12
Figure 2-8. Formulas for load pressure calculations 2-13
圖 2-8. 負載壓力計算公式 2-13
Figure 2-9. Determining general cargo center of gravity 2-14
圖 2-9. 確定一般貨物重心 2-14
Figure 2-10. Determining center of gravity of wheeled vehicle 2-14
圖 2-10. 確定輪式車輛的重心 2-14
Figure 2-11. Compartment method steps 2-15
圖 2-11. 隔間法步驟 2-15
Figure 2-12. Station method steps 2-16
圖 2-12. 站點方法步驟 2-16
Figure 2-13. Effectiveness of tie-down devices 2-18
圖 2-13. 固定裝置的有效性 2-18
Figure 2-14. Calculating tie-down requirements 2-20
圖 2-14. 計算固定需求 2-20
Figure 3-1. Weather conditions conducive to icing 3-3
圖 3-1. 有利於結冰的天氣條件 3-3
Figure 3-3. Depth perception 3-9
圖 3-3. 深度知覺 3-9
Figure 3-4. Desert areas of the world 3-13
圖 3-4. 世界沙漠區域 3-13
Figure 3-5. Sandy desert terrain 3-14
圖 3-5. 沙質沙漠地形 3-14
Figure 3-6. Rocky plateau desert terrain 3-15
圖 3-6. 岩石高原沙漠地形 3-15
Figure 3-7. Mountain desert terrain 3-15
圖 3-7. 山地沙漠地形 3-15
Figure 3-8. Jungle areas of the world 3-20
圖 3-8. 世界的叢林區域 3-20
Figure 3-9. Types of wind 3-25
圖 3-9. 風的類型 3-25
Figure 3-10. Light wind 3-25
圖 3-10. 輕風 3-25
Figure 3-11. Moderate wind 3-26
圖 3-11. 中等風 3-26
Figure 3-12. Strong wind 3-26
圖 3-12。強風 3-26
Figure 3-13. Mountain (standing) wave 3-27
圖 3-13. 山（靜止）波 3-27
Figure 3-14. Cloud formations associated with mountain wave 3-28
圖 3-14. 與山波相關的雲層形成 3-28
Figure 3-15. Rotor streaming turbulence 3-28
圖 3-15. 轉子流動湍流 3-28
Figure 3-16. Wind across a ridge 3-29
圖 3-16. 跨越山脊的風 3-29
Figure 3-17. Snake ridge 3-30
圖 3-17. 蛇脊 3-30
Figure 3-18. Wind across a crown 3-30
圖 3-18. 冠上的風 3-30
Figure 3-19. Shoulder wind 3-31
圖 3-19. 肩部風 3-31
Figure 3-20. Wind across a canyon 3-31
圖 3-20. 峽谷中的風 3-31
Figure 3-21. Mountain takeoff 3-32
圖 3-21. 山地起飛 3-32
Figure 3-22. High reconnaissance flight patterns 3-35
圖 3-22. 高空偵察飛行模式 3-35
Figure 3-23. Computing wind direction between two points 3-36
圖 3-23. 計算兩點之間的風向 3-36
Figure 3-24. Computing wind direction using the circle maneuver 3-37
圖 3-24. 使用圓形機動計算風向 3-37
Figure 3-25. Approach paths and areas to avoid 3-38
圖 3-25. 接近路徑和應避免的區域 3-38
Figure 3-26. Nap-of-the-earth or contour takeoff (terrain flight) 3-40
圖 3-26. 地形飛行或等高線起飛 (地形飛行) 3-40
Figure 3-27. Ridge crossing at a 45-degree angle (terrain flight) 3-41
圖 3-27. 以 45 度角越過山脊（地形飛行）3-41
Figure 3-28. Steep turns or climbs at terrain flight altitudes 3-41
圖 3-28. 在地形飛行高度進行急轉彎或爬升 3-41
Figure 3-29. Flight along a valley (terrain flight) 3-42
圖 3-29. 沿著山谷飛行（地形飛行）3-42
Figure 4-1. Cockpit lighting 4-2
圖 4-1. 駕駛艙照明 4-2
Figure 4-2. Light levels 4-3
圖 4-2. 光照水平 4-3
Figure 4-3. Photopic vision 4-4
圖 4-3. 明視 4-4
Figure 4-4. Mesopic vision 4-4
圖 4-4. 中明視覺 4-4
Figure 4-5. Scotopic vision 4-5
圖 4-5. 暗視力 4-5
Figure 4-6. Day blind spot 4-5
圖 4-6. 日盲點 4-5
Figure 4-7. Night blind spot 4-6
圖 4-7. 夜間盲點 4-6
Figure 4-8. What sensors can see 4-6
圖 4-8. 感測器能看到什麼 4-6
Figure 4-9. Image intensifier 4-7
圖 4-9. 影像增強器 4-7
Figure 4-10. Aviator’s Night Vision Imaging System operational sequence 4-8
圖 4-10. 飛行員夜視成像系統操作序列 4-8
Figure 4-11. Microchannel Plate 4-8
圖 4-11. 微通道板 4-8
Figure 4-12. Phosphor screen 4-8
圖 4-12. 磷光屏 4-8
Figure 4-13. Halo effect 4-9
圖 4-13. 光環效應 4-9
Figure 4-14. Counterweights 4-9
圖 4-14. 平衡重 4-9
Figure 4-17. Infrared crossover 4-13
圖 4-17. 紅外交叉 4-13
Figure 4-18. Parallax effect 4-14
圖 4-18. 視差效果 4-14
Figure 4-19. Thermal image polarity 4-16
圖 4-19. 熱影像極性 4-16
Figure 4-20. Solar radiation 4-17
圖 4-20. 太陽輻射 4-17
Figure 4-21. Heat transmission 4-18
圖 4-21. 熱傳遞 4-18
Figure 4-22. Reflectance 4-18
圖 4-22. 反射率 4-18
Figure 4-23. Absorptance 4-19
圖 4-23. 吸收率 4-19
Figure 4-24. Transmittance 4-19
圖 4-24. 透射率 4-19
Figure 4-25. Emissivity 4-20
圖 4-25. 發射率 4-20
Figure 4-26. Lunar cycle 4-21
圖 4-26. 月相週期 4-21
Figure 4-27. Starlight 4-22
圖 4-27. 星光 4-22
Figure 4-28. Sky glow 4-22
圖 4-28. 天空光輝 4-22
Figure 4-29. Artificial light sources 4-23
圖 4-29. 人工光源 4-23
Figure 4-30. Water vapor/clouds 4-23
圖 4-30. 水蒸氣/雲 4-23
Figure 4-31. Snow 4-25
圖 4-31. 雪 4-25
Figure 4-32. Obscurations/dust 4-25
圖 4-32. 遮蔽/灰塵 4-25
Figure 4-33. Infrared reflectivity value 4-27
圖 4-33. 紅外反射率值 4-27
Figure 4-34. Texture contrast 4-27
圖 4-34. 紋理對比 4-27
Figure 4-35. Snow conditions 4-32
圖 4-35. 雪況 4-32
Figure 4-36. Overwater 4-32
圖 4-36. 水上 4-32
Figure 4-37. Linear perspective 4-35
圖 4-37. 線性透視 4-35
Figure 4-38. Apparent foreshortening 4-35
圖 4-38。明顯的縮短 4-35
Figure 4-39. Known size of objects 4-36
圖 4-39. 已知物體的大小 4-36
Figure 4-40. Terrestrial association 4-36
圖 4-40. 陸地聯繫 4-36
Figure 4-41. Overlapping contours 4-37
圖 4-41. 重疊輪廓 4-37
Figure 4-42. Fading colors/shades 4-37
圖 4-42. 褪色的顏色/陰影 4-37
Figure 4-43. Position of light source 4-38
圖 4-43. 光源位置 4-38
Figure 4-44. Motion parallax 4-38
圖 4-44。運動視差 4-38
Figure 4-45. Laser beam 4-40
圖 4-45. 雷射束 4-40
Figure 4-46. Laser damage 4-41
圖 4-46. 激光損傷 4-41
Figure 4-47. Protective measures 4-41
圖 4-47. 保護措施 4-41
Figure 4-48. Misosis 4-42
圖 4-48. 有絲分裂 4-42
Figure 4-49. Landing light/searchlight 4-43
圖 4-49. 降落燈/探照燈 4-43
Figure 4-50. Supplemental cockpit lighting 4-45
圖 4-50. 補充駕駛艙照明 4-45
Figure 4-51. Stop-turn scanning 4-50
圖 4-51. 停止轉向掃描 4-50
Figure 4-52. Scanning with ten-degree circular overlap 4-51
圖 4-52. 以十度圓形重疊進行掃描 4-51
Figure 4-53. Off-center viewing 4-51
圖 4-53. 偏心觀察 4-51
Figure 4-54. Overwater flight 4-52
圖 4-54. 水上飛行 4-52
Figure 4-55. Takeoff in snow, dust, or sand 4-53
圖 4-55. 在雪、塵或沙中起飛 4-53
Figure 4-56. Dust landing 4-54
圖 4-56. 灰塵著陸 4-54
Figure 4-57. Inverted Y 4-55
圖 4-57. 倒 Y 4-55
Figure 4-58. Steep approach 4-56
圖 4-58. 陡峭進場 4-56
Figure 4-61. Left of course 4-57
圖 4-61。左側的課程 4-57
Figure 4-62. Standard approach path 4-58
圖 4-62. 標準進場路徑 4-58
Figure 4-63. Right of course 4-58
圖 4-63。課程 4-58 的右側
Figure 4-64. North Atlantic Treaty Organization-T 4-59
圖 4-64. 北大西洋公約組織-T 4-59
Figure 5-1. Modes of flight 5-3
圖 5-1. 飛行模式 5-3
Figure 5-2. Route planning map symbols 5-10
圖 5-2. 路徑規劃地圖符號 5-10
Figure 5-3. Sample–joint operations graphic map preparation 5-11
圖 5-3. 樣本–聯合操作圖形地圖準備 5-11
Figure 5-4. Example of an en-route card 5-12
圖 5-4. 在途卡的範例 5-12
Figure 5-5. Example of an objective card 5-13
圖 5-5. 目標卡範例 5-13
Figure 6-1. Horizontal distance 6-5
圖 6-1。水平距離 6-5
Figure 6-2. Stepped-up vertical separation 6-6
圖 6-2. 增強的垂直分離 6-6
Figure 6-3. Echelon formation before breakup 6-9
圖 6-3. 分裂前的梯形編隊 6-9
Figure 6-4. Left break with 10-second interval for landing 6-9
圖 6-4. 左側斷裂，降落間隔 10 秒 6-9
Figure 6-5. Breakup into two elements 6-10
圖 6-5。分解為兩個元素 6-10
Figure 6-7. Two-helicopter section/element 6-14
圖 6-7. 兩架直升機部分/元素 6-14
Figure 6-8. Staggered right and left formation 6-15
圖 6-8. 錯位的右側和左側編隊 6-15
Figure 6-9. Echelon right and left formation 6-16
圖 6-9. Echelon 右側和左側編隊 6-16
Figure 6-10. Trail formation 6-17
圖 6-10. 小徑形成 6-17
Figure 6-11. V-formation 6-18
圖 6-11。V 型隊形 6-18
Figure 6-12. Team combat cruise 6-19
圖 6-12。團隊戰鬥巡航 6-19
Figure 6-13. Flight combat cruise 6-19
圖 6-13. 飛行戰鬥巡航 6-19
Figure 6-14. Combat cruise right 6-20
圖 6-14. 戰鬥巡航右 6-20
Figure 6-15. Combat cruise left 6-20
圖 6-15。戰鬥巡航左轉 6-20
Figure 6-16. Combat trail 6-21
圖 6-16. 戰鬥路徑 6-21
Figure 6-17. Combat spread 6-21
圖 6-17. 戰鬥擴散 6-21
Figure 6-18. Basic combat maneuver circle 6-22
圖 6-18。基本戰鬥機動圈 6-22
Figure 6-19. Tactical turn away 6-23
圖 6-19. 戰術轉向 6-23
Figure 6-20. Tactical turn to 6-24
圖 6-20。戰術轉向 6-24
Figure 6-21. Dig and pinch maneuvers 6-24
圖 6-21. 挖掘和捏合操作 6-24
Figure 6-22. Split turn maneuver 6-25
圖 6-22. 分裂轉向機動 6-25
Figure 6-23. In-place turn 6-25
圖 6-23. 原地轉 6-25
Figure 6-24. Cross turn in or out 6-26
圖 6-24. 交叉轉入或轉出 6-26
Figure 6-25. Cross turn cover (high/low) 6-26
圖 6-25。交叉轉蓋（高/低）6-26
Figure 6-26. Break turn left/right 6-27
圖 6-26. 轉彎左/右 6-27
Figure 6-27. Break turn left/right (high/low) 6-27
圖 6-27. 斷開左轉/右轉（高/低）6-27
Figure 6-28. Shackle turn 6-28
圖 6-28. 鎖鏈轉動 6-28
Figure 6-29. Wake vortex generation 6-30
圖 6-29. 尾流渦旋生成 6-30
Figure 7-1. Stability nomenclature 7-1
圖 7-1. 穩定性命名法 7-1
Figure 7-2. Non-oscillatory motion 7-2
圖 7-2. 非振盪運動 7-2
Figure 7-3. Oscillatory motion 7-3
圖 7-3. 振盪運動 7-3
Figure 7-4. Coefficient of pitching moment versus coefficient of lift 7-4
圖 7-4. 俯仰力矩係數與升力係數的關係 7-4
Figure 7-5. Fixed-wing aircraft center of gravity and aerodynamic center 7-5
圖 7-5. 固定翼飛機的重心和氣動中心 7-5
Figure 7-6. Wing contribution to longitudinal stability 7-5
圖 7-6. 翼對縱向穩定性的貢獻 7-5
Figure 7-7. Negative pitching moment about the aerodynamic center of a positive- cambered airfoil 7-6
圖 7-7. 正弦翼型氣動中心的負俯仰力矩 7-6
Figure 7-9. Negative longitudinal stability of a positive-cambered airfoil 7-7
圖 7-9. 正弦翼型的負縱向穩定性 7-7
Figure 7-10. Lift as a stabilizing moment to the horizontal stabilizer 7-8
圖 7-10. 升力作為水平安定面的穩定力矩 7-8
Figure 7-11. Thrust axis about center of gravity 7-8
圖 7-11. 以重心為中心的推進軸 7-8
Figure 7-12. Positive sideslip angle 7-9
圖 7-12。正側滑角 7-9
Figure 7-13. Directional stability (Beta-sideslip angle versus coefficient of yawing moment) 7-10
圖 7-13. 方向穩定性（Beta-側滑角與偏航力矩係數）7-10
Figure 7-14. Dorsal fin decreases drag 7-10
圖 7-14. 背鰭減少阻力 7-10
Figure 7-15. Fixed-wing aircraft configuration positive yawing moment 7-11
圖 7-15. 固定翼飛機配置正偏航力矩 7-11
Figure 7-16. Horizontal lift component produces sideslip 7-11
圖 7-16. 水平升力元件產生側滑 7-11
Figure 7-17. Positive static lateral stability 7-12
圖 7-17。正靜態側向穩定性 7-12
Figure 7-18. Dihedral angle 7-12
圖 7-18. 二面角 7-12
Figure 7-19. Dihedral stability 7-13
圖 7-19. 二面角穩定性 7-13
Figure 7-20. Adverse yaw 7-14
圖 7-20. 不利偏航 7-14
Figure 7-21. Slipstream and yaw 7-15
圖 7-21. 滑流與偏航 7-15
Figure 7-22. Asymmetric loading (propeller-factor) 7-16
圖 7-22. 非對稱負載（螺旋槳因子）7-16
Figure 7-23. Increasing camber with trailing-edge flap 7-17
圖 7-23. 增加後緣襟翼的俯角 7-17
Figure 7-24. Suction boundary-layer control 7-18
圖 7-24. 吸力邊界層控制 7-18
Figure 7-25. Blowing boundary-layer control 7-18
圖 7-25。吹氣邊界層控制 7-18
Figure 7-26. Vortex generators 7-19
圖 7-26. 渦流發生器 7-19
Figure 7-27. Angle of incidence change with flap deflection 7-19
圖 7-27. 翼面偏轉時入射角的變化 7-19
Figure 7-28. Types of high-lift devices 7-20
圖 7-28. 高升力裝置的類型 7-20
Figure 7-29. Coefficient of lift maximum increase with slotted flap 7-21
圖 7-29. 帶槽襟翼的升力係數最大增益 7-21
Figure 7-30. Coefficient of lift curve 7-22
圖 7-30. 升力係數曲線 7-22
Figure 7-31. Various airfoil angles of attack 7-23
圖 7-31. 各種翼型攻角 7-23
Figure 7-32. Boundary-layer separation 7-23
圖 7-32. 邊界層分離 7-23
Figure 7-34. Typical flow patterns about the t-tail 7-25
圖 7-34. T 形尾翼的典型流動模式 7-25
at high angles of attack 7-25
在高攻角 7-25
Figure 7-37. Stall strip 7-27
圖 7-37. 停滯條 7-27
Figure 7-38. Flapper switch 7-28
圖 7-38. 擺動開關 7-28
Figure 7-39. Spins 7-29
圖 7-39. Spins 7-29
Figure 7-40. Climb angle and rate 7-31
圖 7-40. 攀爬角度和速率 7-31
Figure 7-41. Force-vector diagram for climbing flight 7-32
圖 7-41. 攀爬飛行的力向量圖 7-32
Figure 7-42. Wind effect on maximum climb angle 7-33
圖 7-42. 風對最大爬升角的影響 7-33
Figure 7-43. Full-power polar diagram 7-35
圖 7-43. 全功率極圖 7-35
Figure 7-44. Polar curve 7-36
圖 7-44. 極曲線 7-36
Figure 7-45. Effect of turning flight 7-37
圖 7-45. 轉彎飛行的影響 7-37
Figure 7-46. Effect of load factor on stalling speed 7-38
圖 7-46. 負載因子對失速速度的影響 7-38
Figure 7-49. Landing roll velocity 7-45
圖 7-49. 降落滑行速度 7-45
Figure 7-50. Using flaps to increase camber 7-47
圖 7-50. 使用襟翼增加弦高 7-47
Figure 7-51. Operation of aileron in a turn 7-48
圖 7-51. 轉彎時副翼的操作 7-48
Figure 7-52. Effect of elevator and rudder on moments 7-48
圖 7-52. 升降舵和方向舵對力矩的影響 7-48
Figure 7-54. Adverse moments during takeoff 7-50
圖 7-54. 起飛過程中的不利時刻 7-50
Figure 7-55. Hinge moment 7-52
圖 7-55. 鉸鏈力矩 7-52
Figure 7-56. Aerodynamic balancing using horns 7-52
圖 7-56. 使用喇叭進行氣動平衡 7-52
Figure 7-57. Aerodynamic balancing using a balance board 7-53
圖 7-57. 使用平衡板進行氣動平衡 7-53
Figure 7-58. Aerodynamic balancing using a servo tab 7-53
圖 7-58. 使用伺服片進行氣動平衡 7-53
Figure 7-59. Spoiler used as control surface 7-55
圖 7-59. 用作控制面板的擾流板 7-55
Figure 7-60. Wing flap control 7-55
圖 7-60. 翼襟翼控制 7-55
Figure 7-61. Blade angle affected by revolutions per minute 7-57
圖 7-61. 刀片角度受每分鐘轉速影響 7-57
Figure 7-62. Forces created during single-engine operation 7-60
圖 7-62. 單引擎操作期間產生的力量 7-60
Figure 7-63. Sideslip 7-62
圖 7-63. 側滑 7-62
Figure 7-64. One-engine inoperative flight path 7-63
圖 7-64. 單引擎失效飛行路徑 7-63
Figure 7-65. Windmilling propeller creating drag 7-65
圖 7-65. 風車螺旋槳產生阻力 7-65
Figure 7-66. Required takeoff runway lengths 7-66
圖 7-66. 所需起飛跑道長度 7-66
Figure 7-67. Balanced field length 7-67
圖 7-67. 平衡場長 7-67
Figure 8-1. Lift curve 8-3
圖 8-1. 升力曲線 8-3
Figure 8-2. Ice and frost effects 8-4
圖 8-2. 冰霜效果 8-4
Figure 8-3. Drag curve 8-4
圖 8-3. 拖曳曲線 8-4
Figure 8-4. Tail stall pitchover 8-6
圖 8-4. 尾部失速翻轉 8-6
Figure 8-5. Pneumatic boots 8-9
圖 8-5. 氣動靴 8-9
Figure 8-6. Propeller ice control 8-10
圖 8-6. 螺旋槳冰控制 8-10
Figure 8-7. Wind swell ditch heading 8-18
圖 8-7. 風浪溝道 8-18
Figure 8-8. Single swell 8-19
圖 8-8. 單一膨脹 8-19
Figure 8-9. Double swell (15 knot wind) 8-19
圖 8-9. 雙重膨脹（15 節風）8-19
Figure 8-10. Double swell (30 knot wind) 8-20
圖 8-10. 雙重波浪（30 節風）8-20
Figure 8-11. Swell (50 knot wind) 8-20
圖 8-11. 波浪（50 節風）8-20
Figure 8-12. Effect of microburst 8-23
圖 8-12。微爆的影響 8-23
Figure 9-1. Positive climb 9-4
圖 9-1. 正向爬升 9-4
Figure 9-2. Typical light pattern for airport identification 9-6
圖 9-2. 機場識別的典型光模式 9-6
Figure 9-3. Visual approach slope indicator 9-7
圖 9-3. 視覺接近坡度指示器 9-7
Figure 9-4. Roundout (when tire marks are visible) 9-8
圖 9-4. 圓形輪廓（當輪胎痕跡可見時）9-8
Tables
表格
Table 1-1. Airfoil terminology 1-7
表 1-1. 翼型術語 1-7
Table 1-2. Aircraft reaction to forces 1-17
表 1-2. 飛機對力的反應 1-17
Table 1-3. Bank angle versus torque 1-53
表 1-3. 銀行角度與扭矩 1-53
Table 1-4. Speed of sound variation with temperature and altitude 1-67
表 1-4. 聲速隨溫度和高度的變化 1-67
Table 2-1. Responsibilities 2-9
表 2-1. 責任 2-9
Table 2-2. Internal loading considerations 2-10
表 2-2. 內部載入考量 2-10
Table 2-3. Percentage restraint chart 2-19
表 2-3. 百分比約束圖 2-19
Table 5-1. Mission, enemy, terrain and weather, troops and support available, time available, civil considerations and terrain flight modes 5-4
表 5-1. 任務、敵人、地形和天氣、可用部隊和支援、可用時間、民事考量和地形飛行模式 5-4
Table 5-2. Pickup zone selection considerations 5-5
表 5-2. 取件區域選擇考量 5-5
Table 5-3. Landing zone selection considerations 5-6
表 5-3. 降落區域選擇考量 5-6
Table 5-4. Route planning considerations 5-7
表 5-4. 路徑規劃考量 5-7
Table 5-5. Example of a navigation card 5-12
表 5-5. 導航卡範例 5-12
Table 6-1. Sample lighting conditions 6-7
表 6-1。樣本照明條件 6-7
Table 8-1. Temperature ranges for ice formation 8-2
表 8-1. 冰形成的溫度範圍 8-2
Training Circular (TC) 3-04.4 covers the basic physics of flight; the dynamics associated with rotary- and fixed- wing (FW) aircraft; and the basic tactical flight profiles, formation flight, and maneuvering flight techniques. It contains theoretical and practical concepts from which Army Aviation executes its core competencies.
訓練通告 (TC) 3-04.4 涵蓋了飛行的基本物理學；與旋翼和固定翼 (FW) 飛機相關的動力學；以及基本的戰術飛行型態、編隊飛行和機動飛行技術。它包含了理論和實踐概念，供陸軍航空執行其核心能力。
The principle audience for TC 3-04.4 is all Army aviators and crewmembers. Trainers and educators throughout the Army will also use this publication.
TC 3-04.4 的主要受眾是所有陸軍飛行員和機組成員。陸軍內的訓練者和教育者也將使用本出版物。
Commanders, staffs, and subordinates ensure their decisions and actions comply with applicable United States, international, and in some cases host-nation laws and regulations. Commanders at all levels ensure their Soldiers operate according to the Law of War and rules of engagement. (See Field Manual [FM] 6-27/Marine Corps Training Publication [MCTP] 11-10C.)
指揮官、幕僚和下屬確保他們的決策和行動遵守適用的美國、國際法以及在某些情況下的東道國法律和法規。各級指揮官確保他們的士兵根據戰爭法和交戰規則行動。（參見《野戰手冊》[FM] 6-27/海軍陸戰隊訓練出版物 [MCTP] 11-10C。）
TC 3-04.4 uses joint terms where applicable. Select joint and Army terms and definitions appear in both the glossary and the text. Terms for which TC 3-04.4 is the proponent publication are italicized in the text and are marked with an asterisk (*) in the glossary. Terms and definitions for which TC 3-04.4 is the proponent publication are boldfaced in the text. For other definitions shown in the text, the term is italicized and the number of the proponent publication follows the definition.
TC 3-04.4 在適用時使用聯合術語。選擇的聯合和陸軍術語及定義出現在詞彙表和文本中。TC 3-04.4 為主導出版物的術語在文本中以斜體顯示，並在詞彙表中以星號（*）標記。TC 3-04.4 為主導出版物的術語和定義在文本中以粗體顯示。對於文本中顯示的其他定義，術語以斜體顯示，並在定義後跟隨主導出版物的編號。
TC 3-04.4 applies to the Active Army, the Army National Guard/Army National Guard of the United States, and the United States Army Reserve, unless otherwise stated.
TC 3-04.4 適用於現役陸軍、美國陸軍國民警衛隊/陸軍國民警衛隊及美國陸軍預備役，除非另有說明。
The proponent of this publication is the United States Army Aviation Center of Excellence (USAACE). The preparing agency is the Directorate of Training and Doctrine (DOTD), USAACE. Send comments and recommendations on Department of the Army (DA) Form 2028 (Recommended Changes to Publications and Blank Forms) to Director, DOTD, ATTN: ATZQ-TD (TC 3-04.4). 2218 6th Avenue, Fort Rucker, Alabama 36362; or by e-mail to usarmy.rucker.avncoe.mbx.doctrine-branch@army.mil.
本出版物的提議者是美國陸軍航空卓越中心（USAACE）。編制機構是 USAACE 的訓練與教義局（DOTD）。請將對陸軍部（DA）表格 2028（對出版物和空白表格的建議更改）的意見和建議發送至：DOTD 主任，ATTN: ATZQ-TD（TC 3-04.4），地址：2218 6th Avenue, Fort Rucker, Alabama 36362；或通過電子郵件發送至 usarmy.rucker.avncoe.mbx.doctrine-branch@army.mil。
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One of the underlying premises of Army Aviation is that crewmembers who understand ‘why’ will be better prepared to ‘do’ when confronted with the unexpected. TC 3-04.4 is an excellent reference for Army crewmembers; however, it is not expected that this training circular is all inclusive or a full comprehension of the information will be obtained by simply reading the text. Crewmembers will gain a firm understanding as they gain experience in their particular aircraft; study the tactics, techniques, and procedures (TTP) of their units; and study other sources of information. Crewmembers seeking to hone their skills should review this document periodically to gain new insights.
陸軍航空的基本前提之一是，了解「為什麼」的機組成員在面對意外情況時會更好地準備「去做」。TC 3-04.4 是陸軍機組成員的優秀參考資料；然而，並不期望這本訓練通告是全面的，或僅僅通過閱讀文本就能完全理解信息。機組成員在特定飛機上獲得經驗時，將會獲得堅實的理解；研究他們單位的戰術、技術和程序（TTP）；以及研究其他信息來源。希望磨練技能的機組成員應定期回顧此文件，以獲得新的見解。
This publication ensures that crewmembers understand the basic physics of flight and the dynamics associated with rotary and FW aircraft. A comprehensive understanding of these principles better prepares aviators for flight, transition training, and tactical flight operations. The fundamentals of flight outlined in this TC form the technical base from which Army Aviation executes its core competencies.
本出版物確保機組人員理解飛行的基本物理學以及與旋翼和固定翼飛機相關的動力學。對這些原則的全面理解使飛行員更好地為飛行、過渡訓練和戰術飛行操作做好準備。本技術手冊中概述的飛行基本原則構成了陸軍航空執行其核心能力的技術基礎。
As the United States Army prepares its Soldiers to operate anywhere in the world, this publication describes the unique requirements and flying techniques crewmembers use to successfully operate in various environments. These environments may not always be encountered during home-station training, but may be replicated in constructive, gaming, and virtual training.
隨著美國陸軍準備其士兵在全球任何地方執行任務，本出版物描述了機組成員在各種環境中成功操作所需的獨特要求和飛行技術。這些環境可能並不總是在本地訓練中遇到，但可以在建構性、遊戲和虛擬訓練中重現。
Army Aviation leverages superior night-operation tactics and technologies to gain and maintain advantage over adversaries. To that end, Army crewmembers must be familiar with and capable of performing their missions proficiently at night. The information on night vision systems and night operations in this publication provides the basis for mastering these skills.
陸軍航空利用卓越的夜間作戰戰術和技術來獲得並維持對敵方的優勢。為此，陸軍機組成員必須熟悉並能夠在夜間熟練執行他們的任務。本出版物中有關夜視系統和夜間作戰的信息為掌握這些技能提供了基礎。
All aviators understand they must operate the aircraft safely. Every crewmember must perform the mission effectively and decisively in training and combat. TC 3-04.4 also covers basic tactical flight profiles, formation flight, and maneuvering flight techniques.
所有飛行員都明白他們必須安全地操作飛機。每位機組成員必須在訓練和戰鬥中有效且果斷地執行任務。TC 3-04.4 也涵蓋了基本的戰術飛行型態、編隊飛行和機動飛行技術。
TC 3-04.4 incorporates the following changes:
TC 3-04.4 包含以下變更：
Removes references to the observation helicopter (OH) 58-D.
移除對觀察直升機（OH）58-D 的參考。
Adds the rigid rotor system.
新增剛性轉子系統。
Removes thermal imaging systems.
移除熱成像系統。
Adds forward-looking infrared (FLIR) radar.
新增前視紅外線（FLIR）雷達。
This publication also includes nine chapters:
本出版物還包括九個章節：
Chapter 1 discusses foundational laws and principles with the mechanics of flight.
第一章討論了飛行的基本法則和原則。
Chapter 2 covers weight and balance terms along with center of gravity references.
第二章涵蓋了重量和平衡術語以及重心參考。
Chapter 3 includes descriptions of different flight operation environments such as desert and jungle.
第三章包括對不同飛行操作環境的描述，例如沙漠和叢林。
Chapter 4 focuses on night flying techniques and considerations.
第四章專注於夜間飛行技術和考量。
Chapter 5 discusses terrain flight methods and operational considerations.
第五章討論地形飛行方法和操作考量。
Chapter 6 covers multi-aircraft formation types and maneuvers.
第六章涵蓋多機編隊類型和機動。
Chapter 7 includes fundamental fixed-wing aerodynamics and design.
第七章包括基本的固定翼空氣動力學和設計。
Chapter 8 concentrates on fixed-wing operational environments such as cold weather and mountainous regions.
第八章專注於固定翼作戰環境，例如寒冷氣候和山區。
Chapter 9 discusses fixed-wing night flight fundamentals.
第九章討論固定翼夜間飛行的基本原則。
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Chapter 1
第一章
Aerodynamics of Flight
飛行的空氣動力學
This chapter discusses aerodynamic fundamentals and principles of rotary-wing flight. Understanding these principles facilitates an aviator’s ability to maximize performance of the aircraft. This content relates to flight operations and performance of normal mission tasks. It covers theory and application of aerodynamics for the aviator.
本章討論了旋翼飛行的空氣動力學基本原理。理解這些原理有助於飛行員最大化飛機的性能。這部分內容與飛行操作和正常任務任務的性能相關。它涵蓋了飛行員的空氣動力學理論和應用。
1-1. There are several ways to explain how an airfoil generates lift. This publication discusses Newton’s laws of motion and Bernoulli’s principle. The “Newton” position is that lift is the reaction force on a body caused by deflecting a flow of gas, and the “Bernoulli” position is that lift is generated by a pressure difference across the wing. Both Bernoulli and Newton are correct, and we can use equations developed by each of them to determine the magnitude and direction of the aerodynamic force.
1-1. 有幾種方法可以解釋翼型如何產生升力。本出版物討論了牛頓運動定律和伯努利原理。“牛頓”立場認為升力是由氣流偏轉引起的物體反作用力，而“伯努利”立場則認為升力是由翼面上的壓力差產生的。伯努利和牛頓都是正確的，我們可以使用他們各自發展的方程式來確定空氣動力學力的大小和方向。
NEWTON’S LAWS OF MOTION
牛頓運動定律
1-2. Newton’s three laws of motion are inertia, acceleration, and action/reaction. These laws apply to flight of any aircraft. A working knowledge of the laws and their applications assists in understanding aerodynamic principles discussed in this chapter. Interaction between the laws of motion and aircraft mechanical actions causes the aircraft to fly and allows aviators to control such flight.
1-2. 牛頓的三大運動定律是慣性、加速度和作用/反作用。這些定律適用於任何飛行器的飛行。對這些定律及其應用的基本了解有助於理解本章討論的空氣動力學原則。運動定律與飛行器機械動作之間的相互作用使飛行器能夠飛行，並使飛行員能夠控制這種飛行。
First Law: Inertia
第一定律：慣性
1-3. A body at rest will remain at rest, and a body in motion will remain in motion at the same speed and in the same direction unless acted upon by an external force. Nothing starts or stops without an outside force to bring about or prevent motion. Inertia is a body’s resistance to a change in its state of motion. For a constant mass, force (F) equals mass (M) times acceleration (A), expressed in the formula (F=MA). Mass is then the property of matter that manifests itself as inertia.
1-3. 靜止的物體將保持靜止，運動的物體將以相同的速度和方向繼續運動，除非受到外力的作用。沒有外力的介入，沒有任何事物會開始或停止運動。慣性是物體對其運動狀態變化的抵抗。對於恆定質量，力（F）等於質量（M）乘以加速度（A），用公式（F=MA）表示。質量因此是物質的特性，表現為慣性。
Second Law: Acceleration
第二定律：加速度
1-4. The force required to produce a change in motion of a body is directly proportional to its mass and rate of change in its velocity. Acceleration is a change in velocity with respect to time. It is directly proportional to force and inversely proportional to mass. This takes into account the factors involved in overcoming Newton’s First Law. It covers both changes in direction and speed, including starting up from rest (positive acceleration) and coming to a stop (negative acceleration or deceleration) expressed in the equation A=F/M.
1-4. 產生物體運動變化所需的力與其質量及速度變化率成正比。加速度是相對於時間的速度變化。它與力成正比，與質量成反比。這考慮了克服牛頓第一定律所涉及的因素。它涵蓋了方向和速度的變化，包括從靜止狀態啟動（正加速度）和停止（負加速度或減速），可用方程式 A=F/M 表示。
Third Law: Action/Reaction
第三定律：作用/反作用
1-5. For every action, there is an equal and opposite reaction. When an interaction occurs between two bodies, equal forces in opposite directions are imparted to each body. In a helicopter, the rotor blades move air downward; consequently, the air pushes the rotor blades (and thus the helicopter) in the opposite direction (figure 1-1, page 1-2).
1-5. 每一個行動都有一個相等且相反的反應。當兩個物體之間發生互動時，會對每個物體施加相等的力量，方向相反。在直升機中，旋翼葉片向下移動空氣；因此，空氣將旋翼葉片（以及直升機）推向相反的方向（圖 1-1，頁 1-2）。
Figure 1-1. Aerodynamic lift–explained by Newton’s Law of Motion
圖 1-1. 空氣動力學升力—由牛頓運動定律解釋
BERNOULLI’S PRINCIPLE OF DIFFERENTIAL PRESSURE
伯努利的差壓原理
1-6. Bernoulli’s principle describes the relationship between internal fluid pressure and fluid velocity. It is a statement of the law of conservation of energy and helps explain why an airfoil develops an aerodynamic force. The concept of conservation of energy states energy cannot be created or destroyed and the amount of energy entering a system must also exit. A simple tube with a constricted portion near the center of its length illustrates this principle. An example is using water through a garden hose (figure 1-2). The mass of flow per unit area (cross sectional area of tube) is the mass flow rate. In figure 1-2, the flow into the tube is constant, neither accelerating nor decelerating; thus, the mass flow rate through the tube must be the same at stations 1, 2, or 3. If the cross sectional area at any one of these stations—or any given point—in the tube is reduced, the fluid velocity must increase to maintain a constant mass flow rate to move the same amount of fluid through a smaller area. Fluid speeds up in direct proportion to the reduction in area. Venturi effect is the term used to describe this phenomenon. Figure 1-3, page 1-3, illustrates what happens to mass flow rate in the constricted tube as the dimensions of the tube change.
1-6. 伯努利原理描述了內部流體壓力與流體速度之間的關係。這是能量守恆定律的陳述，並有助於解釋為什麼翼型會產生空氣動力學力。能量守恆的概念指出，能量不能被創造或摧毀，進入系統的能量量必須也要離開。靠近其長度中心的收縮部分的簡單管道說明了這一原理。一個例子是通過花園水管的水（圖 1-2）。每單位面積（管道的橫截面積）的流量質量稱為質量流量率。在圖 1-2 中，流入管道的流量是恆定的，既不加速也不減速；因此，通過管道的質量流量率在站點 1、2 或 3 必須相同。如果在這些站點中的任何一個——或管道中的任何給定點——的橫截面積減小，流體速度必須增加，以保持恆定的質量流量率，將相同量的流體通過較小的面積。流體的速度與面積的減少成正比。文丘里效應是用來描述這一現象的術語。 圖 1-3，頁 1-3，說明了當管道的尺寸改變時，收縮管中的質量流量率會發生什麼變化。
Figure 1-2. Water flow through a tube
圖 1-2. 水流經管道
Figure 1-3. Venturi effect
圖 1-3. 文丘里效應
Venturi Flow
文丘里流量
1-7. While the amount of total energy within a closed system (the tube) does not change, the form of the energy may be altered. Pressure of flowing air may be compared to energy in that the total pressure of flowing air always remains constant, unless energy is added or removed. Fluid flow pressure has two components— static and dynamic pressure. Static pressure is the pressure component measured in the flow but not moving with the flow as pressure is measured. Static pressure is also known as the force per unit area acting on a surface. Dynamic pressure of flow is that component existing as a result of movement of the air. The sum of these two pressures is total pressure. As air flows through the constriction, static pressure decreases as velocity increases. This increases dynamic pressure. Figure 1-4 depicts the bottom half of the constricted area of the tube, which resembles the top half of an airfoil. Even with the top half of the tube removed, the air still accelerates over the curved area because the upper air layers restrict the flow—just as the top half of the constricted tube did. This acceleration causes decreased static pressure above the curved portion and creates a pressure differential caused by the variation of static and dynamic pressures.
1-7. 雖然封閉系統（管道）內的總能量不變，但能量的形式可能會改變。流動空氣的壓力可以與能量相比，因為流動空氣的總壓力始終保持不變，除非能量被添加或移除。流體流動壓力有兩個組成部分——靜壓和動壓。靜壓是指在流動中測量的壓力組件，但不隨流動而移動，作為壓力的測量。靜壓也被稱為作用在表面上的單位面積力。流動的動壓是由空氣運動所產生的組件。這兩種壓力的總和是總壓力。當空氣通過收縮處時，靜壓隨著速度的增加而減少。這增加了動壓。圖 1-4 描繪了管道收縮區域的下半部分，類似於翼型的上半部分。即使去掉了管道的上半部分，空氣仍然在曲面上加速，因為上層空氣限制了流動——就像收縮管道的上半部分一樣。 這種加速導致曲面上方的靜壓降低，並因靜壓和動壓的變化產生壓力差。
Figure 1-4. Venturi flow
圖 1-4. 文丘里流量
Airflow and the Airfoil
氣流與翼型
1-8. Airflow around an airfoil performs similar to airflow through a constriction. As velocity of the airflow increases, static pressure decreases above and below the airfoil. The air usually has to travel a greater distance over the upper surface; thus, there is a greater velocity increase and static pressure decrease over the upper surface than the lower surface. The static pressure differential on the upper and lower surfaces produces about 75 percent of the aerodynamic force, called lift. The remaining 25 percent of the force is produced as a result of action/reaction from the downward deflection of air as it leaves the trailing edge of the airfoil and by the downward deflection of air impacting the exposed lower surface of the airfoil.
1-8. 空氣流經翼型的方式類似於空氣流經收縮處。隨著氣流速度的增加，翼型上方和下方的靜壓力減少。空氣通常需要在上表面上行駛更長的距離；因此，上表面的速度增加和靜壓力減少比下表面更大。上表面和下表面之間的靜壓差產生約 75%的空氣動力學力，稱為升力。剩餘的 25%力是由於空氣在離開翼型的尾緣時向下偏轉的作用/反作用以及空氣向下偏轉撞擊翼型暴露的下表面所產生的。
VECTORS AND SCALARS
向量與標量
1-9. Vectors and scalars are useful tools for the illustration of aerodynamic forces at work. Vectors are quantities with a magnitude and direction. Scalars are quantities described by size alone, such as area, volume, time, and mass.
1-9. 向量和標量是用於說明空氣動力學力作用的有用工具。向量是具有大小和方向的量。標量是僅由大小描述的量，例如面積、體積、時間和質量。
Vector Quantities
向量量值
1-10. Velocity, acceleration, weight, lift, and drag are examples of vector quantities. The direction of vector quantities is as important as the size or magnitude. When two or more forces act upon an object, the combined effect may be represented by the use of vectors. Vectors are illustrated by a line drawn at a particular angle with an arrow at the end. The arrow indicates the direction in which the force is acting. The length of the line (compared to a scale) represents the magnitude of the force.
1-10. 速度、加速度、重量、升力和阻力是向量量的例子。向量量的方向與大小或幅度同樣重要。當兩個或更多的力作用於一個物體時，綜合效果可以通過使用向量來表示。向量是通過在特定角度畫一條線並在末端加上箭頭來表示的。箭頭指示力作用的方向。線的長度（與比例相比）代表力的大小。
Vector Solutions
向量解決方案
1-11. Individual force vectors are useful in analyzing conditions of flight. The chief concern is with combined, or resultant, effects of forces acting on an airfoil or aircraft. The following three methods of solving for the resultant are most commonly used: parallelogram, polygon, and triangulation.
1-11. 個別的力向量在分析飛行條件時非常有用。主要關注的是作用於翼型或飛機上的力的合成或結果效應。以下三種求解結果的常用方法為：平行四邊形法、多邊形法和三角測量法。
Parallelogram Method
平行四邊形法
1-12. This is the most commonly used vector solution in aerodynamics. Using two vectors, lines are drawn parallel to the vectors determining the resultant. If two tugboats push a barge with equal force, the barge moves forward in a direction that is the mean of the direction of both tugboats (figure 1-5).
1-12. 這是氣動力學中最常用的向量解決方案。使用兩個向量，繪製與確定合成向量平行的線。如果兩艘拖船以相等的力量推動一艘駁船，則駁船將朝著兩艘拖船方向的平均方向前進（圖 1-5）。
Figure 1-5. Resultant by parallelogram method
圖 1-5. 由平行四邊形法得到的結果
Polygon Method
多邊形方法
1-13. When more than two forces are acting in different directions, the resultant may be found by using a polygon vector solution. Figure 1-6, page 1-5, shows an example in which one force is acting at 90 degrees with a force of 180 pounds (vector A), a second force acting at 45 degrees with a force of 90 pounds (vector B), and a third force acting at 315 degrees with a force of 120 pounds (vector C). To determine the resultant, draw the first vector beginning at point 0 (the origin) with remaining vectors drawn consecutively. The resultant is drawn from point of origin (0) to the end of the final vector (C).
1-13. 當超過兩個力以不同方向作用時，可以使用多邊形向量解法來找到合力。圖 1-6，頁 1-5，顯示了一個例子，其中一個力以 90 度作用，大小為 180 磅（向量 A），第二個力以 45 度作用，大小為 90 磅（向量 B），第三個力以 315 度作用，大小為 120 磅（向量 C）。要確定合力，從點 0（原點）開始繪製第一個向量，然後依次繪製其餘向量。合力從原點（0）繪製到最後一個向量（C）的末端。
Figure 1-6. Resultant by the polygon method
圖 1-6. 多邊形法的結果
Triangulation Method
三角測量法
1-14. This is a simplified form of a polygon vector solution using only two vectors and connecting them with a resultant vector line. Figure 1-7 shows an example of this solution. By drawing a vector for each of these known velocities and drawing a connecting line between the ends, a resultant velocity and direction can be determined.
1-14. 這是一種簡化的多邊形向量解法，只使用兩個向量並用一條合成向量線將它們連接起來。圖 1-7 顯示了這個解法的一個例子。通過為每個已知速度繪製一個向量，並在末端之間繪製一條連接線，可以確定合成速度和方向。
Figure 1-7. Resultant by the triangulation method
圖 1-7. 由三角測量法得出的結果
Vectors Used
使用的向量
1-15. Figures 1-8 and 1-9, page 1-6, show examples of vectors used to depict forces acting on an airfoil segment and aircraft in flight.
1-15. 圖 1-8 和 1-9，頁 1-6，顯示了用於描繪作用於翼型段和飛行中飛機的力的向量示例。
Figure 1-8. Force vectors on an airfoil segment
圖 1-8. 空氣動力翼段上的力向量
Figure 1-9. Force vectors on aircraft in flight
圖 1-9. 飛行中飛機上的力向量
1-16. Having a firm understanding of airfoil design and the various results of those airfoil designs is necessary for the understanding of aerodynamics. Different airfoil designs and airfoil terminology are explained in this section to better understand the mechanics of flight.
1-16. 對翼型設計及其各種結果有堅實的理解是理解空氣動力學的必要條件。本節將解釋不同的翼型設計和翼型術語，以便更好地理解飛行的機械原理。
AIRFOIL CHARACTERISTICS
翼型特性
1-17. Helicopters and conventional aircraft are able to fly due to aerodynamic forces produced when air passes around the airfoil. An airfoil is any surface such as wing, propeller, rudder, or even a trim tab, which provides aerodynamic force when it interacts with a moving stream of air. (FAA-H-8083-25B) Airfoils are most often associated with production of lift. Airfoils are also used for stability (fin), control (elevator), and thrust or propulsion (propeller or rotor). Certain airfoils, such as rotor blades, combine some of these functions. Airfoils are carefully structured to accommodate a specific set of flight characteristics.
1-17. 直升機和傳統飛機能夠飛行是因為當空氣流過翼型時產生的空氣動力學力。翼型是任何表面，例如機翼、螺旋槳、舵或甚至修整片，當它與移動的空氣流互動時提供空氣動力學力。（FAA-H-8083-25B）翼型最常與升力的產生相關聯。翼型也用於穩定性（鰭）、控制（升降舵）和推進或推力（螺旋槳或轉子）。某些翼型，例如轉子葉片，結合了這些功能中的一些。翼型被精心設計以適應特定的飛行特性。
Airfoil Terminology
翼型術語
1-18. Table 1-1, page 1-7, provides airfoil terms and their definitions common to all aircraft. The first four terms describe the shape of an airfoil. The remaining terms describe development of aerodynamic properties.
1-18. 表 1-1，第 1-7 頁，提供了所有飛機通用的翼型術語及其定義。前四個術語描述了翼型的形狀。其餘術語描述了氣動性能的發展。
Table 1-1. Airfoil terminology | |
Terms | Definitions |
Blade Span | The length of the rotor blade from point of rotation to tip of the blade. |
Wing Span | The maximum distance from wingtip to wingtip. (FAA-H-8083-25B) |
Chord Line | An imaginary straight line drawn through an airfoil from the leading edge to the trailing edge. (FAA-H-8083-25B) |
Chord | The length of the chord line from leading edge to trailing edge; it is the characteristic longitudinal dimension of the airfoil section. (McCormick, 1994) |
Mean Camber Line | A line drawn halfway between the upper and lower surfaces. The chord line connects the ends of the mean camber line. Camber refers to curvature of the airfoil and may be considered curvature of the mean camber line. The shape of the mean camber is important for determining aerodynamic characteristics of an airfoil section. Maximum camber (displacement of the mean camber line from the chord line) and its location help to define the shape of the mean camber line. The location of maximum camber and its displacement from the chord line are expressed as fractions or percentages of the basic chord length. By varying the point of maximum camber, the manufacturer can tailor an airfoil for a specific purpose. The profile thickness and thickness distribution are important properties of an airfoil section. |
Leading-Edge Radius | The radius of curvature given the leading edge shape. |
Flight-Path Velocity | The speed and direction of the airfoil passing through the air. For fixed wing (FW) airfoils, flight-path velocity is equal to true airspeed (TAS). For helicopter rotor blades, flight-path velocity is equal to rotational velocity, plus or minus a component of directional airspeed. (FAA-H-8083-21B) |
Angle of Incidence (FW Aircraft) | The angle between the airfoil chord line and longitudinal axis or other selected reference plane of the airplane. (FAA-H-8083-25B) |
Angle of Incidence (Rotary-Wing Aircraft | The angle between the chord line of a main or tail-rotor blade and rotational relative wind (tip-path plane). It is usually referred to as blade pitch angle. For fixed airfoils, such as vertical fins or elevators, angle of incidence is the angle between the chord line of the airfoil and a selected reference plane of the helicopter. |
Center of Pressure | The point along the chord line of an airfoil through which all aerodynamic forces are considered to act. Since pressures vary on the surface of an airfoil, an average location of pressure variation is needed. As the angle of attack (AOA) changes, these pressures change and center of pressure moves along the chord line. (FAA-H-8083-25B) |
Aerodynamic Center | The point along the chord line where all changes to lift effectively take place. If the center of pressure is located behind the aerodynamic center, the airfoil experiences a nose-down pitching moment. Use of this point by engineers eliminates the problem of center of pressure movement during AOA aerodynamic analysis. (McCormick, 1994) |
Airfoil Types
翼型類型
1-19. The two basic types of airfoils are symmetrical and nonsymmetrical.
1-19. 兩種基本的翼型是對稱型和非對稱型。
Symmetrical
對稱的
1-20. The symmetrical airfoil (figure 1-10, page 1-8) is distinguished by having identical upper and lower surface designs, the mean camber line and chord line being coincident and producing zero lift at zero angle of attack (AOA). A symmetrical design has advantages and disadvantages. One advantage is the center-of-pressure remains relatively constant under varying angles of attack (reducing the twisting force exerted on the airfoil). A symmetrical design also affords ease of construction and reduced cost. The disadvantages are less lift production at a given AOA than a nonsymmetrical design and undesirable stall characteristics.
1-20. 對稱翼型（圖 1-10，頁 1-8）的特點在於其上下表面設計相同，平均弦線和弦線重合，並在零攻角（AOA）下產生零升力。對稱設計有其優缺點。其一個優點是壓力中心在不同攻角下保持相對穩定（減少施加在翼型上的扭轉力）。對稱設計還便於建造並降低成本。缺點是在給定攻角下的升力產生不如非對稱設計，且具有不理想的失速特性。
Figure 1-10. Symmetrical airfoil section
圖 1-10. 對稱翼型截面
Nonsymmetrical (Cambered)
非對稱（拱形）
1-21. The nonsymmetrical airfoil (figure 1-11) has different upper and lower surface designs, with a greater curvature of the airfoil above the chord line than below. The mean camber line and chord line are not coincident. The nonsymmetrical airfoil design produces useful lift even at negative angles of attack. A nonsymmetrical design has advantages and disadvantages. The advantages are more lift production at a given AOA than a symmetrical design, an improved lift to drag ratio, and better stall characteristics. The disadvantages are the center-of-pressure travel can move up to 20 percent of the chord line (creating undesirable torque on the airfoil structure) and greater production costs.
1-21. 非對稱翼型（圖 1-11）具有不同的上表面和下表面設計，上方翼型的曲率大於下方。平均弦線和弦線並不重合。非對稱翼型設計即使在負攻角下也能產生有用的升力。非對稱設計有其優點和缺點。優點是在給定攻角下比對稱設計產生更多的升力、改善升阻比以及更好的失速特性。缺點是壓力中心的移動可能達到弦線的 20%（對翼型結構產生不利的扭矩）以及更高的生產成本。
Figure 1-11. Nonsymmetrical (cambered) airfoil section
圖 1-11. 非對稱（弧形）翼型截面
Blade Twist (Rotary-Wing Aircraft)
刀片扭轉（旋翼飛機）
1-22. Because of lift differential along the blade, it should be designed with a twist to alleviate internal blade stress and distribute the lifting force more evenly along the blade. Blade twist provides higher pitch angles at the root where velocity is low and lower pitch angles nearer the tip where velocity is higher. This increases the induced air velocity and blade loading near the inboard section of the blade.
1-22. 由於葉片上的升力差異，應設計成具有扭轉，以減輕內部葉片應力並更均勻地分配沿葉片的升力。葉片扭轉在根部提供較高的俯仰角，因為那裡的速度較低，而在接近葉尖的地方則提供較低的俯仰角，因為那裡的速度較高。這增加了靠近葉片內側部分的誘導氣流速度和葉片負載。
AIRFLOW AND REACTIONS IN THE ROTOR SYSTEM
轉子系統中的氣流與反應
1-23. The different interactions between airfoil mechanics moving through the atmosphere is described by various terms in this section. The movement of air relative to the rotor system and the resulting movements after the interaction are critical to understanding rotary wing flight.
1-23. 本節中描述了在大氣中運動的翼型力學之間的不同互動。空氣相對於轉子系統的運動及其互動後產生的運動對於理解旋翼飛行至關重要。
Relative Wind
相對風
1-24. Knowledge of relative wind (figure 1-12, page 1-9) is essential for an understanding of aerodynamics and its practical flight application for the aviator. Relative wind is the direction of the airflow produced by an object moving through the air. (FAA-H-8083-25B) The relative wind for an airplane in forward flight flows in a direction parallel with and opposite to the direction of flight; therefore, the actual flight path of the airplane determines the direction of the relative wind.
1-24. 了解相對風（圖 1-12，第 1-9 頁）對於理解空氣動力學及其在飛行員實際飛行中的應用至關重要。相對風是指由物體在空氣中移動所產生的氣流方向。（FAA-H-8083-25B）對於前進飛行的飛機，相對風的方向與飛行方向平行且相反；因此，飛機的實際飛行路徑決定了相對風的方向。
Figure 1-12. Relative wind
圖 1-12. 相對風
Rotational Relative Wind
旋轉相對風
1-25. The rotation of rotor blades as they turn about the mast produces rotational relative wind (figure 1-13). The term rotational refers to the method of producing relative wind. Rotational relative wind flows opposite the physical flight path of the airfoil, striking the blade at 90 degrees to the leading edge and parallel to the plane of rotation, and is constantly changing in direction during rotation. Rotational relative wind velocity is highest at blade tips, decreasing uniformly to zero at axis of rotation (center of the mast).
1-25. 旋翼葉片圍繞主軸旋轉時產生的旋轉相對風（圖 1-13）。旋轉一詞指的是產生相對風的方法。旋轉相對風流向與氣動翼的實際飛行路徑相反，以 90 度的角度撞擊葉片的前緣，並與旋轉平面平行，並在旋轉過程中不斷改變方向。旋轉相對風速在葉片尖端最高，均勻減少至主軸的旋轉軸（主軸中心）為零。
Figure 1-13. Rotational relative wind
圖 1-13. 旋轉相對風
Induced Flow (Downwash)
誘導流（下洗流）
1-26. At flat pitch, air leaves the trailing edge of the rotor blade in the same direction it moved across the leading edge; no lift or induced flow is being produced. As blade pitch angle is increased, the rotor system induces a downward flow of air through the rotor blades creating a downward component of air that is added to the rotational relative wind. Because the blades are moving horizontally, some of the air is displaced downward. The blades travel along the same path and pass a given point in rapid succession. Rotor blade action changes the still air to a column of descending air. This downward flow of air is called induced flow (downwash). Induced flow is the component of air flowing vertically through the rotor system resulting from the production of lift. (FAA-H-8083-21B) It is most pronounced at a hover under no-wind conditions (figure 1-14, page 1-10).
1-26. 在平坦的桨距下，空氣沿著轉子葉片的後緣以與其穿過前緣相同的方向離開；不會產生升力或誘導流動。隨著葉片桨距角的增加，轉子系統會通過轉子葉片誘導出向下的空氣流動，形成一個向下的空氣分量，這個分量會與旋轉的相對風結合。由於葉片是水平移動的，部分空氣會向下位移。葉片沿著相同的路徑移動，並迅速通過某一特定點。轉子葉片的作用將靜止的空氣轉變為一個下降的空氣柱。這種向下的空氣流動稱為誘導流（下洗流）。誘導流是通過轉子系統垂直流動的空氣分量，這是由於升力的產生所致。（FAA-H-8083-21B）在無風條件下的懸停時最為明顯（圖 1-14，第 1-10 頁）。
Figure 1-14. Induced flow (downwash)
圖 1-14. 誘導流（下洗流）
Resultant Relative Wind
結果相對風
1-27. Resultant relative wind (figure 1-15) at a hover is airflow from rotation that is modified by induced flow. (FAA-H-8083-21B) This wind is inclined downward at some angle and opposite the effective flight path of the airfoil, rather than the physical flight path (rotational relative wind). The resultant relative wind also serves as the reference plane for development of lift, drag, and total aerodynamic force (TAF) vectors on the airfoil. When the helicopter has horizontal motion, airspeed further modifies the resultant relative wind. The airspeed component of relative wind results from the helicopter moving through the air. This airspeed component is added to, or subtracted from, the rotational relative wind, depending on whether the blade is advancing or retreating in relation to helicopter movement. Introduction of airspeed relative wind also modifies induced flow. Generally, the downward velocity of induced flow is reduced. The pattern of air circulation through the disk changes when the aircraft has horizontal motion. As the helicopter gains airspeed, the addition of forward velocity results in decreased induced flow velocity. This change results in an improved efficiency (additional lift) being produced from a given blade pitch setting. Section V further covers this process.
1-27. 懸停時的結果相對風（圖 1-15）是由旋轉產生的氣流，並受到誘導流的影響。這股風以某個角度向下傾斜，與氣動翼的有效飛行路徑相反，而不是物理飛行路徑（旋轉相對風）。結果相對風也作為氣動翼上升力、阻力和總空氣動力學力（TAF）向量發展的參考平面。當直升機有水平運動時，空速進一步改變結果相對風。相對風的空速分量是由直升機在空氣中移動所產生的。這個空速分量根據葉片是前進還是後退相對於直升機運動，會加到或減去旋轉相對風。空速相對風的引入也改變了誘導流。一般來說，誘導流的向下速度會減少。當飛機有水平運動時，通過圓盤的氣流循環模式會改變。隨著直升機獲得空速，前進速度的增加導致誘導流速度減少。 此變更導致在給定的葉片角度設定下產生更高的效率（額外的升力）。第五節進一步涵蓋此過程。
Figure 1-15. Resultant relative wind
圖 1-15. 結果相對風
Up Flow (Inflow)
上流（流入）
1-28. Up flow (inflow) is airflow approaching the rotor disk from below as the result of some rate of descent. Up flow also occurs as a result of blades flapping down or an updraft, which alter the AOA.
1-28. 向上氣流（進氣流）是指由於某種下降速率而從下方接近轉子盤的氣流。向上氣流也會因為葉片向下拍打或上升氣流而發生，這會改變攻角（AOA）。
ROTOR BLADE ANGLES
旋翼葉片角度
1-29. Mechanical and aerodynamic angles of airfoils have various effects on engine power demands and aerodynamic properties. Angle of incidence is one angle that is easier to control being that it is a mechanical angle. Angle of attack is harder to control because of its relationship with the atmosphere. Correlating the relationship between these two angles expands the understanding of power management and permission planning.
1-29. 機械和氣動角度對翼型的引擎功率需求和氣動特性有各種影響。入射角是一個較易控制的角度，因為它是機械角度。攻角則較難控制，因為它與大氣的關係。關聯這兩個角度之間的關係擴展了對功率管理和許可規劃的理解。
Angle of Incidence
入射角
1-30. Angle of incidence is the angle between the chord line of a main or tail rotor blade and the rotational relative wind of the rotor system (tip-path plane) (figure 1-16, page 1-11). It is a mechanical angle rather than an aerodynamic angle and is sometimes referred to as blade pitch angle. In the absence of induced flow, AOA and angle of incidence are the same. Whenever induced flow, up flow (inflow), or airspeed modifies relative wind, then AOA is different from angle of incidence. Collective input and cyclic feathering change angle of incidence. A change in angle of incidence changes AOA, which changes the coefficient of lift, thereby changing the lift produced by the airfoil.
1-30. 入射角是主旋翼或尾旋翼葉片的弦線與旋翼系統的旋轉相對風（尖端路徑平面）之間的角度（圖 1-16，第 1-11 頁）。這是一個機械角度，而不是一個空氣動力學角度，有時被稱為葉片俯仰角。在沒有誘導流的情況下，攻角和入射角是相同的。每當誘導流、上升流（進流）或空速改變相對風時，攻角就會與入射角不同。集體輸入和循環羽化會改變入射角。入射角的變化會改變攻角，進而改變升力係數，從而改變翼型產生的升力。
Angle of Attack
攻角
1-31. AOA is the angle between the airfoil’s chord line and relative wind. (FAA-H-8083-21B) The relative wind associated with AOA is the resultant relative wind. AOA is an aerodynamic angle (figure 1-6). It can change with no change in angle of incidence. Several factors may change the rotor blade AOA. Aviators control some of those factors; others occur automatically due to rotor system design. Aviators adjust AOA through normal control manipulation; even with no aviator input, however, AOA changes as an integral part of travel of the rotor blade through the rotor-disk arc. This continuous process of change accommodates rotary-wing flight. Aviators have little control over blade flapping and flexing, gusty wind, or turbulent air conditions. AOA is one of the primary factors determining amount of lift and drag produced by an airfoil.
1-31. AOA 是翼型弦線與相對風之間的角度。(FAA-H-8083-21B) 與 AOA 相關的相對風是合成相對風。AOA 是一個空氣動力學角度（圖 1-6）。它可以在不改變入射角的情況下改變。幾個因素可能會改變旋翼葉片的 AOA。飛行員控制其中一些因素；其他因素則因旋翼系統設計而自動發生。飛行員通過正常的控制操作來調整 AOA；然而，即使沒有飛行員的輸入，AOA 也會隨著旋翼葉片在旋翼盤弧內的運動而改變。這一持續的變化過程適應了旋翼飛行。飛行員對葉片的拍打和彎曲、陣風或湍流空氣條件的控制有限。AOA 是決定翼型產生的升力和阻力的主要因素之一。
Figure 1-16. Angle of incidence and angle of attack
圖 1-16. 入射角與攻角
Effects of Airflow
氣流的影響
1-32. As AOA is increased, there is a greater acceleration of air atop the airfoil. This results in a larger pressure differential between the top and bottom of the airfoil, producing a larger aerodynamic force. If AOA is increased beyond a critical angle, flow across the top of the airfoil will be disrupted, boundary layer separation will occur, and a stall results. When this occurs, lift rapidly decreases, drag rapidly increases, and the airfoil ceases to fly.
1-32. 隨著攻角（AOA）的增加，翼型上方的氣流加速會更大。這導致翼型上下之間的壓力差增大，產生更大的空氣動力學力。如果攻角超過臨界角，翼型上方的氣流將會受到干擾，邊界層分離將發生，並導致失速。當這種情況發生時，升力迅速減少，阻力迅速增加，翼型將停止飛行。
ROTOR BLADE ACTIONS
轉子葉片動作
1-33. Different types of rotor systems react in different ways while rotating around the central axis. Rotor system design and their specific design attributes aid in the understanding of aircraft limits and capabilities.
1-33. 不同類型的轉子系統在圍繞中央軸旋轉時會以不同的方式反應。轉子系統的設計及其特定設計屬性有助於理解飛機的限制和能力。
Understanding the individual rotor blade actions of a specific rotor system in flight strengthens the overall understanding of how that system works as a whole.
了解特定旋翼系統在飛行中的個別旋翼葉片行為，有助於加強對該系統整體運作方式的理解。
Rotation
旋轉
1-34. Rotation of rotor blades is the most basic movement of the rotor system and produces rotational relative wind. During hovering, rotation of the rotor system produces airflow over the rotor blades. Figure 1-17, page 1-12, illustrates a typical rotor system with an arbitrary rotor diameter of 40 feet and rotor speed of 320 revolutions per minute (RPM) used to demonstrate rotational velocities. In this example, blade tip velocity is 670 feet per second, or 397 knots. At the blade root—nearer the rotor shaft or blade attachment point—blade speed is much less as the distance traveled at the smaller radius is much less. Halfway between the root and tip (point A in figure 1-17) blade speed is 198.5 knots, or one-half tip speed. Blade speed varies according to the distance or radius from the center of the main rotor shaft. While the airspeed differential between root and tip is extreme, the lift differential is more extreme because lift varies as the square of the velocity (see lift equation on page 1-26). As velocity doubles, lift increases four times. The lift at point A in figure 1-17 would be only one-fourth as much as lift at the blade tip—assuming the airfoil shape and AOA are the same at both points.
1-34. 轉子葉片的旋轉是轉子系統最基本的運動，並產生旋轉相對風。在懸停時，轉子系統的旋轉會在轉子葉片上產生氣流。圖 1-17（第 1-12 頁）顯示了一個典型的轉子系統，具有 40 英尺的任意轉子直徑和 320 轉每分鐘（RPM）的轉子速度，用於演示旋轉速度。在這個例子中，葉片尖端速度為 670 英尺每秒，或 397 節。在葉片根部——靠近轉子軸或葉片連接點——葉片速度要小得多，因為在較小半徑上行進的距離要小得多。在根部和尖端之間的中點（圖 1-17 中的 A 點）葉片速度為 198.5 節，或為尖端速度的一半。葉片速度根據距離或從主轉子軸中心的半徑而變化。雖然根部和尖端之間的空氣速度差異極大，但升力差異更為極端，因為升力隨速度的平方變化（見第 1-26 頁的升力方程）。當速度加倍時，升力增加四倍。 在圖 1-17 中，A 點的升力僅為葉片尖端升力的四分之一——假設兩點的翼型形狀和攻角相同。
Figure 1-17. Blade rotation and blade speed
圖 1-17. 刀片旋轉與刀片速度
Feathering
羽化
1-35. Feathering is the action that changes the pitch angle of the rotor blades by rotating them around their feathering (spanwise) axis. (FAA-H-8083-21B) (figure 1-18).
1-35. 羽化是通過圍繞其羽化（跨幅）軸旋轉旋翼葉片來改變其俯仰角的動作。(FAA-H-8083-21B) (圖 1-18)。
Figure 1-18. Feathering
圖 1-18. 羽化
Collective Feathering
集體羽化
1-36. Collective feathering changes angle of incidence equally and in the same direction on all rotor blades simultaneously. This action changes AOA, which changes coefficient of lift (CL) and affects overall lift of the rotor system.
1-36. 集體羽毛變化在所有旋翼葉片上同時以相同的方向改變入射角。這一動作改變了攻角，進而改變升力係數（CL）並影響整個旋翼系統的升力。
Cyclic Feathering
循環羽化
1-37. Cyclic feathering changes angle of incidence differentially around the rotor system. Cyclic feathering creates a differential lift in the rotor system by changing the AOA differentially across the rotor system. Aviators use cyclic feathering to control attitude of the rotor system. It is the means to control rearward tilt of the rotor (blowback) caused by flapping action and (along with blade flapping) counteract dissymmetry of lift (section V). Cyclic feathering causes attitude of the rotor disk to change but does not change amount of lift the rotor system is producing.
1-37. 循環羽化使旋翼系統周圍的迎角發生差異性變化。循環羽化通過在旋翼系統中差異性地改變攻角來產生旋翼系統的差異升力。飛行員使用循環羽化來控制旋翼系統的姿態。這是控制由拍打動作引起的旋翼向後傾斜（回流）的手段，並且（連同葉片拍打）抵消升力的不對稱性（第五節）。循環羽化使旋翼盤的姿態發生變化，但不改變旋翼系統產生的升力大小。
Flapping
拍打
1-38. The vertical movement of a blade about a flapping hinge is called flapping. (FAA-H-8083-21B) It occurs in response to changes in lift due to changing velocity or cyclic feathering (figure 1-19). No flapping occurs when the tip-path plane is perpendicular to the mast. The flapping action alone, or along with cyclic feathering, controls dissymmetry of lift (section V). Flapping is the primary means of compensating for dissymmetry of lift.
1-38. 刀片圍繞擺動鉸鏈的垂直運動稱為擺動（FAA-H-8083-21B）。這是對於由於速度變化或循環羽毛調整而引起的升力變化的反應（圖 1-19）。當尖端路徑平面與桅杆垂直時，不會發生擺動。擺動動作本身或與循環羽毛調整一起控制升力的不對稱（第 V 節）。擺動是補償升力不對稱的主要手段。
Figure 1-19. Flapping in directional flight
圖 1-19. 方向性飛行中的拍打
1-39. Flapping also allows the rotor system to tilt in the desired direction in response to cyclic input. See figure 1-20, figure 1-21, figure 1-22 (page 1-14), and figure 1-23 (page 1-14) for depictions of flapping as it occurs throughout the rotor disk.
1-39. 擺動還允許旋翼系統根據循環輸入向所需方向傾斜。請參見圖 1-20、圖 1-21、圖 1-22（第 1-14 頁）和圖 1-23（第 1-14 頁）以查看旋翼盤中擺動的示意圖。
Figure 1-20. Flapping (advancing blade 3 o’clock position)
圖 1-20. 拍打（前進葉片 3 點鐘位置）
Figure 1-21. Flapping (retreating blade 9-o’clock position)
圖 1-21. 拍打（退後葉片 9 點鐘位置）
Figure 1-22. Flapping (blade over the aircraft nose)
圖 1-22. 拍打（葉片在飛機機頭上方）
Figure 1-23. Flapping (blade over the aircraft tail)
圖 1-23. 拍動（葉片在飛機尾部上方）
1-40. In the semirigid rotor system, a blade is not free to flap independently of the other blades because they are affixed through the hub. The blades form one continuous unit moving together on a common teetering hinge. This hinge allows one blade to flap up as the opposite blade flaps down, although blade flex limits the amount of blade flapping. In the fully articulated rotor system, blades flap individually about a horizontal hinge pin. Therefore, each blade is free to move up and down independently from all of the other blades. Aircraft design can reduce excessive flapping in several ways; for example, a forward tilt of the transmission and mast helps minimize flapping and installation of a synchronized elevator or stabilator (utility helicopter (UH)-60/attack helicopter (AH)-64) helps maintain the desired fuselage attitude to reduce flapping.
1-40。在半剛性轉子系統中，葉片不能獨立於其他葉片自由擺動，因為它們通過樞軸固定在一起。這些葉片形成一個連續的單元，沿著共同的擺動鉸鏈一起運動。這個鉸鏈允許一片葉片向上擺動，而對面的葉片則向下擺動，儘管葉片的彎曲限制了擺動的幅度。在完全關節式轉子系統中，葉片圍繞一個水平鉸鏈釘獨立擺動。因此，每片葉片可以獨立於其他所有葉片自由上下移動。飛機設計可以通過幾種方式減少過度擺動；例如，傳動裝置和桅杆的前傾有助於最小化擺動，而安裝同步升降舵或穩定翼（通用直升機（UH）-60/攻擊直升機（AH）-64）有助於保持所需的機身姿態以減少擺動。
1-41. In a rigid rotor system, each blade flaps about flexible sections of the root, which are rigidly attached to the rotor hub. This rotor system is mechanically simple, but structurally complex because operating loads must
1-41. 在剛性轉子系統中，每個葉片圍繞根部的柔性部分擺動，這些部分與轉子中心剛性連接。這個轉子系統在機械上簡單，但在結構上複雜，因為操作負載必須
be absorbed in bending rather than through hinges. Rigid rotor systems tend to behave like fully articulated systems through aerodynamics, but lack flapping or lead/lag hinges.
專注於彎曲而非通過鉸鏈。剛性轉子系統傾向於通過空氣動力學表現得像完全關節化的系統，但缺乏拍動或前後鉸鏈。
Lead and Lag (Hunting)
引導與滯後（狩獵）
1-42. The fore (lead) and aft (lag) movement of the rotor blade in the plane of rotation is lead and lag. (FAA- H-8083-21B) This movement responds to changes in angular velocity (figure 1-24, page 1-15). This rotor blade action can only occur in a fully articulated rotor system, in which the system is equipped with a vertical hinge pin (drag hinge) or elastomeric bearing providing a pivot point for each blade to move independently. In directional flight, pitch angle and the AOA of the blades are constantly changing. These changes in AOA cause changes in blade drag. To prevent undue bending stress on the blades and blade root, the blade is free to move fore and aft in the plane of rotation. The need to lead and lag is due to the Coriolis force. It is governed by the law of conservation of angular momentum. This law states a body will continue to have the same rotational momentum unless acted on by an outside force. Two factors determine the rotational (angular) momentum— distance of the center of gravity (CG) from the center of rotation and rotational speed. If the CG moves closer to the center of rotation, the rotational speed must increase. If the CG moves farther away from the axis of rotation, rotational velocity will decrease (figure 1-24).
1-42. 旋翼葉片在旋轉平面中的前進（引導）和後退（滯後）運動稱為引導和滯後。（FAA-H-8083-21B）這種運動對角速度的變化作出反應（圖 1-24，頁 1-15）。這種旋翼葉片的動作僅能在完全關節式旋翼系統中發生，該系統配備有垂直鉸鏈銷（拖曳鉸鏈）或彈性軸承，為每個葉片提供獨立運動的支點。在定向飛行中，葉片的俯仰角和攻角（AOA）不斷變化。這些攻角的變化會導致葉片阻力的變化。為了防止對葉片和葉片根部施加過度的彎曲應力，葉片可以在旋轉平面中自由前後移動。引導和滯後的需求是由於科里奧利力。這是由角動量守恆定律所支配。該定律指出，物體將繼續保持相同的旋轉動量，除非受到外力的作用。兩個因素決定了旋轉（角）動量——重心（CG）距離旋轉中心的距離和旋轉速度。如果重心移近旋轉中心，則旋轉速度必須增加。 如果重心離旋轉軸越遠，旋轉速度將會減少（圖 1-24）。
Figure 1-24. Lead and lag
圖 1-24. 領先與滯後
Lead
鉛
1-43. As a blade flaps up, the CG of the blade (figure 1-24, point C) moves inboard toward the axis of rotation, producing a smaller radius of travel. The blade speeds up in reaction to this CG change, causing the blade to lead a few degrees ahead of its normal position in the tip-path plane (figure 1-24, point D). This motion relieves stress that would have been imposed on the blade structure.
1-43. 當葉片向上擺動時，葉片的重心（圖 1-24，點 C）向內移動至旋轉軸，產生較小的運動半徑。葉片因應這一重心變化而加速，導致葉片在尖端路徑平面中領先於其正常位置幾度（圖 1-24，點 D）。這一運動減輕了本會施加於葉片結構上的應力。
Lag
延遲
1-44. As a blade flaps down, the CG of the blade (figure 1-24, point A) moves outboard away from the axis of rotation, producing a greater radius of travel. The blade slows down in reaction to this CG change, causing the blade to lag a few degrees behind its normal position in the tip-path plane (figure 1-24, point B). This motion relieves stress that would have been imposed on the blade structure.
1-44. 當葉片向下拍打時，葉片的重心（圖 1-24，點 A）向外側移動，遠離旋轉軸，產生更大的運動半徑。葉片因應這一重心變化而減速，導致葉片在尖端路徑平面中落後於其正常位置幾度（圖 1-24，點 B）。這一運動減輕了本會施加在葉片結構上的應力。
Semirigid Rotor System
半剛性轉子系統
1-45. Because of the design (under slung) of the semirigid rotor system, no change occurs in the travel radius of the CG of the blade associated with blade flapping (figure 1-25, page 1-16). The angular velocity of the blade does not change. Drag does impose significant stresses on the blade roots; a drag brace is normally installed at the blade root to absorb some of these bending forces.
1-45. 由於半剛性轉子系統的設計（下懸式），與葉片擺動相關的重心行程半徑不會發生變化（圖 1-25，頁 1-16）。葉片的角速度不變。阻力確實對葉片根部施加了顯著的應力；通常在葉片根部安裝阻力支撐以吸收部分這些彎曲力。
Figure 1-25. Under slung design of semirigid rotor system
圖 1-25. 懸掛式半剛性轉子系統設計
Rigid Rotor System
剛性轉子系統
1-46. The rigid rotor system behaves more like a fully articulated rotor system and its characteristics are based on how much flexibility that the blade’s construction contains. The blades’ flexible root provides physical behavior similar to mechanical or elastomeric hinges, allowing the neutralizing forces in the same manner as Lead or Lag and Flapping do with other rotor designs.
1-46. 嚴格的轉子系統更像是一個完全關節式的轉子系統，其特性基於葉片結構的柔韌性。葉片的柔性根部提供了類似於機械或彈性鉸鏈的物理行為，允許以與其他轉子設計中前滯和擺動相同的方式中和力量。
1-47. The rigid rotor system, sometimes referred to as bearingless, is mechanically simple, but structurally complex because operating loads must be absorbed in bending rather than through hinges. In this system, the blade roots are rigidly attached to the rotor hub. Rigid rotor systems tend to behave like fully articulated systems through aerodynamics, but lack flapping or lead/lag hinges. Instead, the blades accommodate these motions by bending. They cannot flap or lead/lag, but they can be feathered. These rotor systems offer the best properties of both semirigid and fully articulated systems. The rigid rotor system is very responsive and is usually not susceptible to mast bumping like the semirigid or articulated systems because the rotor hubs are mounted solid to the main rotor mast. This allows the rotor and fuselage to move together as one entity and eliminates much of the oscillation usually present in the other rotor systems. Other advantages of the rigid rotor include a reduction in the weight and drag of the rotor hub and a larger flapping arm, which significantly reduces control inputs. Without the complex hinges, the rotor system becomes much more reliable and easier to maintain than the other rotor configurations. A disadvantage of this system is the quality of ride in turbulent or gusty air. Because there are no hinges to help absorb the larger loads, vibrations are felt in the cabin much more than with other rotor head designs.
1-47. 嚴格轉子系統，有時稱為無軸承系統，機械上簡單，但結構上複雜，因為操作負載必須通過彎曲而非鉸鏈來吸收。在這個系統中，葉片根部與轉子中心嚴密連接。嚴格轉子系統通過空氣動力學表現得像完全關節系統，但缺乏拍動或前後鉸鏈。相反，葉片通過彎曲來適應這些運動。它們不能拍動或前後移動，但可以調整角度。這些轉子系統提供了半剛性和完全關節系統的最佳特性。嚴格轉子系統反應非常敏捷，通常不易受到像半剛性或關節系統那樣的桅杆碰撞影響，因為轉子中心是固定安裝在主轉子桅杆上的。這使得轉子和機身能夠作為一個整體一起移動，並消除了其他轉子系統中通常存在的許多振盪。嚴格轉子的其他優點包括減少轉子中心的重量和阻力，以及更大的拍動臂，這顯著減少了控制輸入。 沒有複雜的鉸鏈，轉子系統變得比其他轉子配置更可靠且更易於維護。這個系統的一個缺點是在湍流或陣風中乘坐的舒適性。因為沒有鉸鏈來幫助吸收較大的負載，振動在駕駛艙中感受到的程度比其他轉子頭設計要高得多。
HELICOPTER DESIGN AND CONTROL
直升機設計與控制
1-48. Helicopter design continues to evolve due to better materials and building processes. More inherent control has been integrated for a more stable platform. Understanding the forces acting on the aircraft and what design features are counteracting those forces aides in the correlation of helicopter flight knowledge.
1-48. 直升機設計因為更好的材料和建造工藝而持續演變。為了提供更穩定的平台，已整合了更多內在控制。理解作用於飛機上的力量以及哪些設計特徵在抵消這些力量，有助於直升機飛行知識的相關性。
Gyroscopic Precession
陀螺進動
1-49. The phenomenon of precession occurs in rotating bodies that manifest an applied force 90 degrees after application in the direction of rotation. Although precession is not a dominant force in rotary-wing aerodynamics, aviators and designers must consider it, as turning rotor systems exhibit some of the characteristics of a gyro. Figure 1-26, page 1-17, illustrates effects of precession on a typical rotor disk when force is applied at a given point. A downward force applied to the disk at point A results in a downward movement of the disk at point B.
1-49. 預旋現象發生在旋轉物體中，當施加的力在旋轉方向上以 90 度的角度出現。雖然預旋在旋翼氣動力學中並不是主導力量，但飛行員和設計師必須考慮到它，因為轉動的旋翼系統顯示出某些陀螺的特徵。圖 1-26，頁 1-17，說明了在特定點施加力時，預旋對典型旋翼盤的影響。在 A 點施加的向下力量導致在 B 點的旋翼盤向下移動。
Figure 1-26. Gyroscopic precession
圖 1-26. 陀螺進動
1-50. Table 1-2 depicts reactions to forces applied to a spinning rotor disk by control input or wind gusts.
1-50. 表 1-2 描述了對旋轉轉子盤施加的控制輸入或風陣力的反應。
Table 1-2. Aircraft reaction to forces
表 1-2. 飛機對力量的反應
Force Applied to Rotor Disk | Aircraft Reaction |
Up at nose | Roll right |
Up at tail | Roll left |
Up on right side | Nose up |
Up on left side | Nose down |
1-51. This behavior explains some fundamental effects occurring during various helicopter maneuvers. For example, the helicopter behaves differently when rolling into a right turn than when rolling into a left turn. During roll into a right turn, the aviator must correct for a nose-down tendency to maintain altitude. This correction is required because precession causes a nose-down tendency. During a roll into a left turn, precession causes a nose-up tendency. Aviator input required to maintain altitude is different during a left versus right turn as gyroscopic precession acts in opposite directions.
1-51. 這種行為解釋了在各種直升機機動過程中發生的一些基本效應。例如，直升機在向右轉彎時的滾轉行為與向左轉彎時不同。在向右轉彎的滾轉過程中，飛行員必須修正向下的趨勢以維持高度。這種修正是必要的，因為進動會導致向下的趨勢。在向左轉彎的滾轉過程中，進動則會導致向上的趨勢。為了維持高度，飛行員在左轉和右轉時所需的輸入是不同的，因為陀螺進動的作用方向相反。
Rotor Head Control
旋翼頭控制
1-52. The control of the rotor head traditionally involves two main inputs such as a collective and cyclic pitch control. Different airframe designs incorporate more sophisticated systems that interact with these two main controls for enhanced controllability.
1-52. 旋翼頭的控制傳統上涉及兩個主要輸入，即集體和循環桨距控制。不同的機身設計整合了更複雜的系統，這些系統與這兩個主要控制相互作用，以增強可控性。
Cyclic and Collective Pitch
循環與集體變距
1-53. Aviator inputs to collective and cyclic pitch controls are transmitted to the rotor blades through a complex system. This system consists of levers, mixing units, input servos, stationary and rotating swashplates, and pitch- change arms (figure 1-27, page 1-18). In its simplest form, movement of collective pitch control causes stationary and rotating swashplates mounted centrally on the rotor shaft to rise and descend. The movement of cyclic pitch control causes the swashplates to tilt; the direction of tilt is controlled by the direction in which the aviator moves the cyclic (figure 1-28, page 1-18).
1-53. 飛行員對集體和循環桨距控制的輸入通過一個複雜的系統傳遞到旋翼葉片。該系統由槓桿、混合單元、輸入伺服器、靜止和旋轉的搖臂板以及桨距變更臂組成（圖 1-27，頁 1-18）。在其最簡單的形式中，集體桨距控制的移動使安裝在旋翼軸中央的靜止和旋轉搖臂板上升和下降。循環桨距控制的移動使搖臂板傾斜；傾斜的方向由飛行員移動循環的方向控制（圖 1-28，頁 1-18）。
Figure 1-27. Rotor head control systems
圖 1-27. 轉子頭控制系統
Figure 1-28. Stationary and rotating swashplates tilted by cyclic control
圖 1-28. 由循環控制傾斜的靜止和旋轉的擺盤
Tilted Swashplate Assembly
傾斜擺盤組件
1-54. Figure 1-29, page 1-19, illustrates a swashplate tilted 2 degrees at two positions, points B and D. Points A and C form the axis about which the tilt occurs. At that axis, the swashplate remains at zero degrees. When the swashplate is moved, pitch-change arms transmit the resulting motion change to the rotor blade. As the pitch-change arms move up and down with each rotation of the swashplate, blade pitch constantly increases or decreases. If the aviator applies cyclic control to tilt the rotor, adding collective pitch does not change the tilt of the swashplate and rotor. It simply moves the swashplate upward so pitch is increased equally on all blades simultaneously, thereby increasing AOA and total lift.
1-54. 圖 1-29，頁 1-19，顯示了一個在兩個位置（點 B 和 D）傾斜 2 度的擺盤。點 A 和 C 形成了傾斜發生的軸心。在該軸心上，擺盤保持在零度。當擺盤移動時，變距臂將產生的運動變化傳遞到旋翼葉片。隨著變距臂在每次擺盤旋轉時上下移動，葉片的俯仰角不斷增加或減少。如果飛行員施加循環控制來傾斜旋翼，增加集體俯仰角不會改變擺盤和旋翼的傾斜。它只是將擺盤向上移動，使所有葉片的俯仰角同時均等增加，從而增加攻角和總升力。
Figure 1-29. Stationary and rotating swashplates tilted in relation to mast
圖 1-29. 與桅杆傾斜的靜止和旋轉的斜盤
Pitch-Change Arms
變音臂
1-55. Figure 1-30 illustrates how pitch-change arms move up and down on the tilted swashplate. The rate of vertical change throughout the rotation is not uniform. Vertical movement is larger during the 30 degrees of rotation at point A than at points B and C. This variation repeats during each 90 degrees of rotation. The rate of vertical movement is lowest at the low and high points of the swashplate and highest when the pitch-change arms pass by the tilt axis of the swashplate.
1-55. 圖 1-30 顯示了變距臂如何在傾斜的搖擺盤上上下移動。整個旋轉過程中的垂直變化速率並不均勻。在 A 點的 30 度旋轉期間，垂直運動比 B 點和 C 點更大。這種變化在每 90 度的旋轉中重複。垂直運動的速率在搖擺盤的低點和高點時最低，而在變距臂經過搖擺盤的傾斜軸時最高。
Figure 1-30. Pitch-change arm rate of movement over 90 degrees of travel
圖 1-30. 音高變化臂在 90 度行程內的運動速率
Cyclic Pitch Change
循環變距
1-56. Figure 1-31, page 1-20, shows a change in cyclic pitch (cyclic feathering). This causes rotor blades to climb from point A to point B, then dive or descend from point B to point A. In this way, the rotor is tilted in the direction of desired flight.
1-56. 圖 1-31，頁 1-20，顯示了循環桨距（循環羽化）的變化。這使得旋翼葉片從點 A 上升到點 B，然後從點 B 下降或潛降到點 A。這樣，旋翼就朝著所需的飛行方向傾斜。
Figure 1-31. Rotor flapping in response to cyclic input
圖 1-31. 轉子因循環輸入而擺動
1-57. To pass through points A and B, the blades must flap up and down on a hinge or teeter on a trunnion. At the lowest flapping point (point A), the blades would appear to be at their lowest pitch angle; at the highest flapping point (point B), they would be at their highest pitch angle. If only aerodynamic considerations were involved, this might be true. However, gyroscopic precession (figure 1-26, page 1-17) causes these points to be separated by 90 degrees of rotation.
1-57. 為了通過點 A 和 B，葉片必須在鉸鏈上上下拍動或在支座上搖擺。在最低拍動點（點 A），葉片似乎處於最低的俯仰角；在最高拍動點（點 B），它們則處於最高的俯仰角。如果僅涉及氣動力學考量，這可能是正確的。然而，陀螺進動（圖 1-26，頁 1-17）使這些點之間的旋轉角度相隔 90 度。
1-58. A cyclic movement decreases blade pitch at one point in the rotor disk while increasing blade pitch by the same amount 180 degrees of travel later. A decrease in lift resulting from a decrease in blade pitch angle and AOA causes the blade to flap down; the blade reaches its maximum downflapping displacement 90 degrees later in the direction of rotation. An increase in lift resulting from an increase in blade pitch angle and AOA causes the blade to flap up; the blade reaches its maximum upflapping displacement 90 degrees later in the direction of rotation. Figure 1-32, page 1-21, shows the resulting change to the rotor disk’s attitude. The cyclic pitch causing blade flap must be placed on the blades 90 degrees of rotation before the lowest and highest flap are desired. This 90 degrees of phase lag due to gyroscopic precession is accounted for when rotors are designed, and it ensures when the cyclic is pushed forward, the action tilts the swashplate assembly to place the cyclic pitch accordingly. To tilt the rotor disk forward, the lowest cyclic pitch on the blade needs to be over the right side of the helicopter and the highest cyclic pitch over the left side. The rotor always tilts in the direction in which the aviator moves the cyclic.
1-58. 循環運動在轉子盤的一個點上減少葉片的桨距，同時在 180 度的行程後增加相同數量的葉片桨距。由於葉片桨距角和攻角的減少導致升力減少，這使得葉片向下擺動；葉片在旋轉方向上 90 度後達到其最大下擺位移。由於葉片桨距角和攻角的增加導致升力增加，這使得葉片向上擺動；葉片在旋轉方向上 90 度後達到其最大上擺位移。圖 1-32，頁 1-21，顯示了轉子盤姿態的變化。造成葉片擺動的循環桨距必須在期望的最低和最高擺動之前 90 度的旋轉位置上施加在葉片上。這 90 度的相位延遲是由於陀螺前進效應，在設計轉子時已經考慮到，並確保當循環向前推時，動作會傾斜擺盤組件以相應地放置循環桨距。要使轉子盤向前傾斜，葉片上的最低循環桨距需要位於直升機的右側，而最高循環桨距則位於左側。 轉子總是朝著飛行員移動循環控制桿的方向傾斜。
Typical Design Features
典型設計特徵
1-59. Figure 1-33, page 1-21, illustrates a typical design feature used in most four-bladed rotor systems offsetting cyclic control input 90 degrees from where the aviator desires rotor tilt. Rotor control input locations are the left lateral servo (point A), right lateral servo (point B), and fore and aft servo (point C). Each servo is offset 45 degrees from the position corresponding to its name. The fore and aft input servo, for example, is not located at the nose or tail position but at the right front about halfway between the nose and 3 o’clock position. Similarly, the left lateral servo is located halfway between the nose and 9 o’clock position. The right lateral servo is halfway between the tail and 3 o’clock position. Locations of the input servos account for part of the offset the aviator needs to correct for gyroscopic precession. In addition, the rotor blade has a pitch-change horn extending ahead of the blade in the plane of rotation about 45 degrees. A connecting rod, called a pitch-change rod, transmits aviator control inputs from the input servos to the pitch-change horn. The design of the pitch- change horn, coupled with placement of the servo and tilt of the swashplate, provides the total offset.
1-59. 圖 1-33，頁 1-21，顯示了大多數四葉片轉子系統中使用的典型設計特徵，將循環控制輸入偏移 90 度，與飛行員希望的轉子傾斜位置不同。轉子控制輸入位置包括左側伺服器（點 A）、右側伺服器（點 B）和前後伺服器（點 C）。每個伺服器的位置相對於其名稱偏移 45 度。例如，前後輸入伺服器並不位於機頭或機尾位置，而是位於右前方，約在機頭和 3 點鐘位置之間的中間點。同樣，左側伺服器位於機頭和 9 點鐘位置之間的中間點。右側伺服器位於機尾和 3 點鐘位置之間的中間點。輸入伺服器的位置考慮了飛行員需要修正的部分陀螺進動偏移。此外，轉子葉片有一個變距角喇叭，向前延伸約 45 度，位於旋轉平面內。一根稱為變距桿的連接桿將飛行員的控制輸入從輸入伺服器傳遞到變距角喇叭。 變距喇叭的設計，加上伺服器的放置和搖臂的傾斜，提供了總偏移量。
Figure 1-32. Cyclic feathering
圖 1-32. 循環羽毛效應
Figure 1-33. Input servo and pitch-change horn offset
圖 1-33. 輸入伺服和變音喇叭偏移
Cyclic Pitch Variation
循環變距調整
1-60. Figure 1-34 illustrates typical cyclic pitch variation of a blade through one revolution with cyclic pitch control full forward. Degrees shown are for a typical aircraft rotor system; figures would vary with the type of helicopter. As described in the previous paragraph, the input servos and pitch-change horns are offset. With cyclic pitch control in the full forward position, the blade pitch angle is highest at the 9 o’clock position and lowest at the 3 o’clock position. The pitch angle begins decreasing as it passes the 9 o’clock position and continues to decrease until it reaches the 3 o’clock position. The pitch begins to increase and reaches the maximum pitch angle at the 9 o’clock position. Blade pitch angles over the nose and tail are about equal.
1-60. 圖 1-34 顯示了在循環變距控制全前進狀態下，葉片在一圈旋轉中的典型循環變距變化。顯示的度數是針對典型的飛機旋翼系統；數字會因直升機類型而異。如前一段所述，輸入伺服器和變距角喇叭是偏移的。在循環變距控制全前進位置時，葉片的變距角在 9 點鐘位置最高，在 3 點鐘位置最低。變距角在通過 9 點鐘位置時開始減少，並持續減少直到達到 3 點鐘位置。變距開始增加，並在 9 點鐘位置達到最大變距角。葉片在機頭和機尾的變距角大致相等。
1-61. Figure 1-34 shows that blades reach a point of lowest flapping over the nose 90 degrees in the direction of rotation from the point of lowest pitch angle. Highest flapping occurs over the tail 90 degrees in the direction of rotation from the point of the highest pitch angle. Simply stated, the force (pitch angle) causing blade flap must be applied to the blade 90 degrees of rotation before the point where the aviator desires maximum blade flap.
1-61. 圖 1-34 顯示，葉片在距離最低俯仰角點 90 度的旋轉方向上，達到最低拍動點。最高拍動發生在距離最高俯仰角點 90 度的旋轉方向上。簡而言之，造成葉片拍動的力（俯仰角）必須在飛行員希望達到最大葉片拍動的點之前的 90 度旋轉處施加於葉片上。
1-62. A pattern similar to figure 1-34 could be constructed for other cyclic positions in the circle of cyclic travel. In each case, the same principles apply. Points of highest and lowest flapping are located 90 degrees in the direction of rotation from the points of highest and lowest blade pitch.
1-62. 可以為循環旅行的圓周上的其他循環位置構建類似於圖 1-34 的模式。在每種情況下，相同的原則適用。最高和最低拍動的點位於從最高和最低葉片角度的點向旋轉方向 90 度的位置。
Figure 1-34. Cyclic pitch variation–full forward, low pitch
圖 1-34. 循環變距–全前進，低變距
Fuselage Hovering Attitude
機身懸停姿態
1-63. The hovering attitude varies between aircraft designs. There are a number of reasons why a fuselage has a specific hovering attitude. Aviators should be familiar with the hovering characteristics of their respective aircraft.
1-63. 懸停姿態因飛機設計而異。機身具有特定懸停姿態的原因有很多。飛行員應熟悉各自飛機的懸停特性。
Single-Rotor Helicopter
單旋翼直升機
1-64. The design of most fully articulated rotor systems includes an offset between the main rotor mast and blade attachment point. Centrifugal force acting on the offset tends to hold the mast perpendicular to the tip- path plane (figure 1-35, page 1-23). When the rotor disk is tilted left to counteract the translating tendency, the fuselage follows the main rotor mast and hangs slightly low on the left side.
1-64. 大多數完全關節式轉子系統的設計包括主轉子桅杆與葉片連接點之間的偏移。作用於偏移的離心力傾向於使桅杆垂直於尖端路徑平面（圖 1-35，頁 1-23）。當轉子盤向左傾斜以抵消平移趨勢時，機身跟隨主轉子桅杆，並在左側稍微低懸。
1-65. A fuselage suspended under a semirigid rotor system remains level laterally unless the load is unbalanced or the tail rotor gearbox is lower than the main rotor (figure 1-36, page 1-23). The fuselage remains level because there is no offset between the rotor mast and the point where the rotor system is attached to the mast (trunnion bearings). Because trunnion bearings are centered on the mast, the mast does not tend to follow the tilt of the rotor disk during hover. In addition, the mast does not tend to remain perpendicular to the tip-path plane as it does with a fully articulated rotor system. Instead, the mast tends to hang vertically under the trunnion bearings, even when the rotor disk is tilted left to compensate for translating tendency (figure 1-36, point B). Because the mast remains vertical, the fuselage hangs level laterally unless other forces affect it.
1-65. 懸掛在半剛性旋翼系統下的機身在負載不平衡或尾旋翼齒輪箱低於主旋翼的情況下，會保持側向水平（圖 1-36，頁 1-23）。機身保持水平是因為旋翼桿與旋翼系統連接點（支撐軸承）之間沒有偏移。由於支撐軸承位於桿的中心，桿在懸停時不會隨著旋翼盤的傾斜而傾斜。此外，桿不會像完全關節旋翼系統那樣保持垂直於尖端路徑平面。相反，即使旋翼盤向左傾斜以補償平移趨勢，桿也傾向於在支撐軸承下垂直懸掛（圖 1-36，點 B）。由於桿保持垂直，機身在沒有其他力量影響的情況下會保持側向水平。
Figure 1-35. Fully articulated rotor system
圖 1-35. 完全關節式轉子系統
Figure 1-36. Semirigid rotor system
圖 1-36. 半剛性轉子系統
1-66. When there is forward tilt of the mast, the tail rotor gearbox is probably lower than the main rotor. Main rotor thrust above tail rotor thrust to the right causes the fuselage to tilt laterally left (figure 1-37, page 1-24). Although main rotor thrust to the left is equal to tail rotor thrust to the right, it acts at a greater distance from the CG, creating a greater turning moment on the fuselage. This is more pronounced in helicopters with semirigid rotor systems than those with fully articulated rotor systems. Tail rotor thrust acting at the plane of rotation of the main rotor would not change the attitude of the fuselage. The main rotor mast in semirigid and fully articulated rotor systems may be designed with a forward tilt relative to the fuselage. During forward flight, forward tilt provides a level longitudinal fuselage attitude, resulting in reduced parasite drag; during hover, it results in a tail-low fuselage attitude.
1-66. 當桅杆向前傾斜時，尾旋翼齒輪箱可能低於主旋翼。主旋翼的推力高於尾旋翼推力向右，導致機身向左側傾斜（圖 1-37，頁 1-24）。儘管主旋翼向左的推力等於尾旋翼向右的推力，但它在重心（CG）處的距離更大，從而在機身上產生更大的轉矩。在半剛性旋翼系統的直升機中，這種情況比在完全關節旋翼系統的直升機中更為明顯。作用於主旋翼旋轉平面的尾旋翼推力不會改變機身的姿態。半剛性和完全關節旋翼系統中的主旋翼桅杆可能設計為相對於機身向前傾斜。在前飛行中，向前傾斜提供了一個水平的縱向機身姿態，從而減少寄生阻力；在懸停時，則導致機身尾部較低的姿態。
Figure 1-37. Effect of tail-low attitude on lateral hover attitude
圖 1-37. 尾部低姿態對側向懸停姿態的影響
Tandem-Rotor Helicopter
串聯旋翼直升機
1-67. In tandem-rotor helicopters, the forward and aft rotor systems are tilted forward due to transmission mounting design. This tilt helps decrease excessive nose-low attitudes in forward flight and allows the aircraft to ground or water taxi forward. Most tandem-rotor helicopters hover at a nose-high attitude of about 5 degrees. Some models automatically compensate for this nose-high attitude through automatic programming of the rotor systems.
1-67. 在串列旋翼直升機中，前後旋翼系統因傳動安裝設計而向前傾斜。這種傾斜有助於減少前飛行中的過度低頭姿態，並允許飛機在地面或水面上向前滑行。大多數串列旋翼直升機在約 5 度的高頭姿態下懸停。一些型號通過旋翼系統的自動編程自動補償這種高頭姿態。
Pendular Action
擺動動作
1-68. The fuselage of the helicopter has considerable mass and is suspended from a single point (single-rotor helicopters). It is free to oscillate laterally or longitudinally like a pendulum. Normally, the fuselage follows rules governing pendulums, balance, and inertia. Rotor systems, however, follow rules governing aerodynamics, dynamics, and gyroscopes. These two unrelated systems have been designed to work well together, in spite of apparent conflict. Other factors, such as overcontrolling, cyclic-control response, and shift of attitude, affect the relationship of the rotor system and fuselage.
1-68. 直升機的機身具有相當的質量，並且懸掛在一個單一的點上（單旋翼直升機）。它可以像擺一樣自由地在橫向或縱向上擺動。通常，機身遵循擺動、平衡和慣性的規則。然而，旋翼系統則遵循空氣動力學、動力學和陀螺儀的規則。這兩個不相關的系統被設計成能夠良好協同工作，儘管表面上存在衝突。其他因素，如過度控制、循環控制反應和姿態變化，影響旋翼系統和機身之間的關係。
Overcontrolling
過度控制
1-69. Overcontrolling occurs when the aviator moves the cyclic control stick, causing rotor tip-path changes not reflected in corresponding fuselage-attitude changes. Correct cyclic control movements (free of overcontrol) cause the rotor tip-path and fuselage to move in unison.
1-69. 過度控制發生在飛行員移動循環控制桿時，導致旋翼尖端路徑的變化未反映在相應的機身姿態變化中。正確的循環控制動作（不受過度控制影響）使旋翼尖端路徑和機身同步移動。
Cyclic Control Response
循環控制反應
1-70. The rotor response to cyclic control input on a single-rotor helicopter has no lag. Rotor blades respond instantly to the slightest touch of cyclic control. The fuselage response to lateral cyclic is noticeably different from the response to fore and aft cyclic applications. Normally, considerably more fore and aft cyclic movement is required to achieve the same fuselage response as achieved from an equal amount of lateral cyclic. This is not a lag in rotor response; rather as figure 1-38, page 1-25, shows, it is due to more fuselage inertia around the lateral axis than around the longitudinal axis. For single-rotor helicopters, the normal corrective device for the lateral axis is the addition of a synchronized elevator or stabilator attached to the tail boom. This device produces lift forces keeping the fuselage of the helicopter in proper alignment with the rotor at normal flight airspeed.
1-70. 單旋翼直升機的轉子對循環控制輸入的反應沒有延遲。轉子葉片對循環控制的最輕觸立即作出反應。機身對側向循環的反應與對前後循環的反應明顯不同。通常，為了達到與相等側向循環相同的機身反應，需要 considerably 更多的前後循環運動。這不是轉子反應的延遲；而是如圖 1-38，頁 1-25 所示，這是由於機身在側向軸周圍的慣性比在縱向軸周圍的慣性更大。對於單旋翼直升機，側向軸的正常修正裝置是增加一個同步的升降舵或穩定舵，該裝置附加在尾桿上。這個裝置產生升力，保持直升機的機身在正常飛行空速下與轉子保持正確對齊。
This alignment helps reduce blade flapping and extends the allowable CG range of the helicopter; however, it is ineffective at slow airspeeds.
這種對齊有助於減少刀片擺動並擴大直升機的允許重心範圍；然而，在低空速下效果不佳。
Figure 1-38. Cyclic control response around the lateral and longitudinal axes
圖 1-38. 繞側向和縱向軸的循環控制反應
Shift of Attitude
態度的轉變
1-71. Fuel cells normally have a slight aft CG. As fuel is used, a slight shift to a more nose-low attitude occurs. Because of fuel expenditure and lighter fuselage, cruise attitudes tend to shift slightly lower. As fuel loads are reduced, drag affects the lighter fuselage more, resulting in a slight shift to a more nose-down attitude during flight.
1-71. 燃料電池通常具有輕微的後重心。隨著燃料的消耗，會發生輕微的向前低頭姿態的轉變。由於燃料的消耗和機身變輕，巡航姿態往往會稍微降低。隨著燃料負載的減少，阻力對較輕的機身影響更大，導致在飛行過程中輕微轉變為更向下的姿態。
1-72. A number of forces act upon an aircraft while in flight. While it is not necessary to memorize the lift equation, an aviator benefits significantly from a thorough understanding of the forces described in this section. An aviator should strive to explain the relationships of these forces and the results on the aircraft.
1-72. 在飛行過程中，有多種力量作用於飛機上。雖然不必記住升力方程，但飛行員對本節所描述的力量有透徹的理解將大有裨益。飛行員應努力解釋這些力量之間的關係及其對飛機的影響。
TOTAL AERODYNAMIC FORCE
總空氣動力學力
1-73. As air flows around an airfoil, a pressure differential develops between the upper and lower surfaces. The differential, combined with air resistance to passage of the airfoil, creates a force on the airfoil. This is known as TAF (figure 1-39). TAF acts at the center of pressure on the airfoil and is normally inclined up and rear. TAF, sometimes called resultant force, may be divided into two components, lift and drag.
1-73. 當空氣流過翼型時，上下表面之間會產生壓力差。這個壓力差，加上空氣對翼型通過的阻力，會在翼型上產生一個力。這被稱為 TAF（圖 1-39）。TAF 作用於翼型的壓力中心，通常向上和向後傾斜。TAF，有時稱為合力，可以分為兩個分量：升力和阻力。
Figure 1-39. Total aerodynamic force
圖 1-39. 總空氣動力學力
LIFT AND LIFT EQUATION
升力與升力方程式
1-74. Lift is the component of the total aerodynamic force on a airfoil and acts perpendicular to the relative wind. (FAA-H-8083-21B) (figure 1-40, page 1-26). The resultant relative wind is the referenced relative wind associated with lift.
1-74. 升力是作用於翼型的總空氣動力學力的組成部分，並且垂直於相對風。(FAA-H-8083-21B)（圖 1-40，第 1-26 頁）。結果相對風是與升力相關的參考相對風。
Figure 1-40. Forces acting on an airfoil
圖 1-40. 作用於翼型上的力
1-75. The illustration of the lift equation, accompanied by a simple explanation, helps understanding of how lift is generated. The point is to understand what an aviator can or cannot change in the equation.
1-75. 升力方程的插圖，配以簡單的解釋，有助於理解升力是如何產生的。重點在於理解飛行員在方程中可以或不能改變什麼。
1-76. The shape or design of the airfoil and AOA determine the coefficient of lift. Aviators have no control over airfoil design. However, they do have direct control over AOA. The aviator cannot affect rho (ρ) or surface area of the airfoil (S). With respect to relative wind velocity or airspeed (V), an increase in rotor RPM has a greater effect on lift than an increase in airspeed.
1-76. 翼型或設計及攻角（AOA）決定了升力係數。飛行員無法控制翼型設計。然而，他們對攻角有直接控制。飛行員無法影響空氣密度（ρ）或翼面的面積（S）。就相對風速或空速（V）而言，轉子轉速（RPM）的增加對升力的影響大於空速的增加。
DRAG
拖曳
1-77. Drag is the net aerodynamic force parallel to the relative wind, usually the sum of two components: induced drag and parasite drag. (FAA-H-8083-25B) (figure 1-40). The resultant relative wind is the referenced relative wind associated with drag. Drag is the force opposing the motion of an airfoil through the air.
1-77. 阻力是與相對風平行的淨空氣動力學力，通常是兩個組件的總和：誘導阻力和寄生阻力。(FAA-H-8083-25B) (圖 1-40)。結果相對風是與阻力相關的參考相對風。阻力是反對翼型在空氣中運動的力量。
Drag Equation
拖曳方程式
1-78. The illustration of the drag equation accompanied by a simple explanation (in addition to the lift equation) helps understanding of how drag is generated. The point is to understand what an aviator can and cannot change.
1-78. 拖曳方程的插圖配以簡單的解釋（除了升力方程）有助於理解拖曳是如何產生的。重點在於理解飛行員可以和不能改變的事項。
1-79. The shape or design of the airfoil and AOA largely determine the coefficient of drag. The aviator has no control over airfoil design but has direct control over AOA. This is one of two elements of the drag equation the aviator can change. However, an aviator cannot affect ρ which is density of the air. S represents surface area of the airfoil, a design factor also unaffected by aviator input. Finally, V represents relative wind velocity or airspeed and is the only other factor an aviator can change.
1-79. 翼型或設計及攻角（AOA）在很大程度上決定了阻力係數。飛行員無法控制翼型設計，但可以直接控制攻角。這是飛行員可以改變的阻力方程中的兩個要素之一。然而，飛行員無法影響ρ，即空氣的密度。S 代表翼面的表面積，這是一個設計因素，也不受飛行員的影響。最後，V 代表相對風速或空速，是飛行員可以改變的唯一其他因素。
Types of Drag
阻力類型
1-80. Total drag acting on a helicopter is the sum of the three types of drag—parasite, profile, and induced drag. Curve D in figure 1-41, page 1-27, shows total drag and represents the sum of the other three curves.
1-80. 直升機所受的總阻力是三種阻力的總和——寄生阻力、輪廓阻力和誘導阻力。圖 1-41（第 1-27 頁）中的曲線 D 顯示了總阻力，並代表其他三條曲線的總和。
Parasite Drag
寄生拖曳
1-81. Parasite drag is incurred from the non-lifting portions of the aircraft. It includes form drag, skin friction, and interference drag associated with the fuselage, engine cowlings, mast and hub, landing gear, wing stores, external load, and rough finish paint. Parasite drag increases with airspeed and is the dominant type at high airspeeds. Curve A in figure 1-41 shows parasite drag.
1-81. 寄生阻力是由飛機的非升力部分產生的。它包括與機身、引擎罩、桅杆和輪轂、起落架、翼載、外部負載以及粗糙表面塗料相關的形狀阻力、表面摩擦和干擾阻力。寄生阻力隨著空速的增加而增加，並且在高空速下是主要的阻力類型。圖 1-41 中的曲線 A 顯示了寄生阻力。
Profile Drag
檔案拖曳
1-82. Profile drag is incurred from frictional resistance of the blades passing through the air. It does not change significantly with AOA of the airfoil section but increases moderately at high airspeeds. At high airspeeds, profile drag increases rapidly with onset of blade stall or compressibility. Curve B in figure 1-41 shows profile drag.
1-82. 輪廓阻力是由於葉片通過空氣時產生的摩擦阻力。它不會因為氣動翼截面的攻角而顯著改變，但在高空速時會適度增加。在高空速下，輪廓阻力隨著葉片失速或可壓縮性的出現而迅速增加。圖 1-41 中的曲線 B 顯示了輪廓阻力。
Induced Drag
誘導阻力
1-83. Induced drag is incurred as a result of production of lift. Higher angles of attack, which produce more lift, also generate downward velocities and vortices that increase induced drag. In rotary-wing aircraft, induced drag decreases with increased aircraft airspeed. Curve C in figure 1-41 shows induced drag.
1-83. 由於產生升力而產生的誘導阻力。較高的攻角會產生更多的升力，同時也會產生向下的速度和渦流，這會增加誘導阻力。在旋翼飛機中，隨著飛機空速的增加，誘導阻力會減少。圖 1-41 中的曲線 C 顯示了誘導阻力。
Drag/Power/Airspeed Relationship
拖曳/功率/空速關係
1-84. Figure 1-41 illustrates the relationship between drag, power, and airspeed.
1-84. 圖 1-41 顯示了阻力、功率和空速之間的關係。
Figure 1-41. Drag and airspeed relationship
圖 1-41. 拖曳與空速關係
Aircraft Performance and Power Curves
飛機性能與功率曲線
1-85. Drag is a major component used in conjunction with flight testing and performance data to develop performance planning charts found in operator manuals which explains the similar appearance in these charts (figure 1-41). Performance planning charts allow aviators to compute expected performance data based on various weather conditions, loading configurations, and airspeeds. This data is required to determine predicted
1-85. 拖曳是與飛行測試和性能數據一起使用的主要組件，用於開發操作手冊中找到的性能規劃圖表，這些圖表解釋了這些圖表中相似的外觀（圖 1-41）。性能規劃圖表允許飛行員根據各種天氣條件、載荷配置和空速計算預期的性能數據。這些數據是確定預測所需的。
airspeeds, torques, and fuel flows during various mission profiles. Key information required for performance planning includes maximum range airspeed, maximum endurance airspeed, maximum rate-of-climb airspeed and the torques and fuel flows associated with those airspeeds.
在各種任務配置期間的空速、扭矩和燃料流量。性能規劃所需的關鍵信息包括最大航程空速、最大耐久空速、最大爬升率空速以及與這些空速相關的扭矩和燃料流量。
1-86. Maximum range airspeed is an airspeed that should allow the helicopter to fly the furthest distance. It is determined by flying where airspeed intersects the lowest amount of total drag (point E on figure 1-41, page 1- 27). However, due to flight testing and aircraft performance, cruise charts are used to determine torque and fuel flows required to maintain that airspeed. Because cruise charts are not drag charts, it can be noted the lowest point of a drag chart does not necessarily match the lowest point of the power required curve in a cruise chart.
1-86. 最大範圍空速是應該允許直升機飛行最遠距離的空速。它是通過飛行在空速與總阻力最低點交叉的地方來確定的（圖 1-41，頁 1-27 的 E 點）。然而，由於飛行測試和飛機性能，巡航圖表用於確定維持該空速所需的扭矩和燃料流量。由於巡航圖表不是阻力圖，因此可以注意到，阻力圖的最低點不一定與巡航圖中所需功率曲線的最低點相匹配。
1-87. Maximum endurance airspeed is an airspeed that allows the helicopter to remain flying the most amount of time. It can be found on the power required curve of the cruise chart where power required is at its lowest and not necessarily where total drag is lowest on the drag chart.
1-87. 最大耐久空速是指允許直升機飛行最長時間的空速。它可以在巡航圖的功率需求曲線上找到，當功率需求達到最低點時，而不一定是在阻力圖上總阻力最低的地方。
1-88. Maximum rate-of-climb airspeed is maximum endurance airspeed combined with maximum torque available to achieve the fastest rate of climb.
1-88. 最大爬升率空速是最大耐久空速與可用最大扭矩的結合，以實現最快的爬升率。
CENTRIFUGAL FORCE AND CONING
離心力與圓錐形
1-89. A helicopter rotor system depends primarily on rotation to produce relative wind, which develops the aerodynamic force required for flight. This action subjects the rotor system to forces peculiar to all rotating masses. One of the forces produced is centrifugal force. The apparent force tends to make rotating bodies move away from the center of rotation. The rotating blades of a helicopter produce very high centrifugal loads on the hub and blade attachment assemblies. In rotary-wing aircraft, this is the dominant force affecting the rotor system; all other forces act to modify it. As a rotor system begins to turn, the blades begin to rise from the static position because of centrifugal force. At operating speed, the blades extend straight out although the rotor system is at flat pitch (zero degree angle of incidence) and are not producing lift. As the aircraft develops lift during takeoff and flight, the blades rise above the straight-out position and assume a coned position. The amount of coning depends on RPM, gross weight, and gravitational (G) forces experienced during flight. Figure 1-42, page 1-29, illustrates the various positions of a rotor blade in the static position, at flat pitch, and when generating lift. Excessive coning can occur if RPM is too low, gross weight is too high, an aircraft is flying in turbulent air, or the G-forces experienced are too high. This excessive coning can cause undesirable stresses on the components and a decrease in lift because of a decrease in effective disk area (figure 1-43, page 1-29).
1-89. 直升機旋翼系統主要依賴旋轉來產生相對風，這會產生飛行所需的空氣動力學力量。這一行為使旋翼系統受到所有旋轉質量特有的力量影響。產生的力量之一是離心力。這種表觀力量傾向於使旋轉物體遠離旋轉中心。直升機的旋轉葉片對樞軸和葉片連接組件產生非常高的離心負荷。在旋翼飛機中，這是影響旋翼系統的主導力量；所有其他力量都作用於修正它。當旋翼系統開始旋轉時，葉片因離心力而從靜止位置上升。在運行速度下，葉片雖然旋翼系統處於平坦的俯仰（零度入射角），但仍然向外伸展，並未產生升力。隨著飛機在起飛和飛行過程中產生升力，葉片會高於直伸位置並呈現圓錐形位置。圓錐形的程度取決於轉速、總重量和在飛行過程中經歷的重力（G）力量。 圖 1-42，頁 1-29，顯示了旋翼葉片在靜止位置、平坦桨距和產生升力時的各種位置。如果轉速過低、總重量過高、飛機在湍流空氣中飛行，或所經歷的重力過高，則可能會發生過度圓錐現象。這種過度圓錐現象可能會對組件造成不良應力，並因有效圓盤面積減少而導致升力下降（圖 1-43，頁 1-29）。
Figure 1-42. Effects of centrifugal force and lift
圖 1-42. 離心力和升力的影響
Figure 1-43. Decreased disk area (loss of lift caused by coning)
圖 1-43. 磁碟面積減少（由於圓錐形造成的升力損失）
TORQUE REACTION AND ANTITORQUE ROTOR (TAIL ROTOR)
扭矩反應與反扭矩旋翼（尾旋翼）
1-90. According to Newton’s law of action/reaction, action created by the turning rotor system causes the fuselage to react by turning in the opposite direction. The fuselage reaction to torque turning the main rotor is
1-90。根據牛頓的作用/反作用定律，旋轉轉子系統產生的作用使機身以相反的方向反應。機身對於扭矩轉動主旋翼的反應是
torque effect. Torque must be counteracted to maintain control of the aircraft; the antitorque rotor does this (figure 1-44). In the tandem rotor or coaxial helicopters, the two rotor systems turn in opposite directions, effectively canceling the torque effect. Most rotary-wing aircraft have a single main rotor and require a tail rotor or other means to counter the torque effect. As the initial action is generated by engine power (torque) turning the main rotor system, this torque will necessarily vary with power applied or the maneuver performed. The tail rotor is designed as a variable-pitch, antitorque rotor to accommodate the varying effects of such a system. The tail rotor is usually driven by the main transmission through a drive shaft arrangement leading to its position at the end of the tail boom. The engine power required to motor and control the tail rotor can be significant. The aviator must consider this during performance planning for varying conditions and situations. It is easy to understand why various emergency procedures have been written to compensate for problems such as loss of engine power, insufficient engine power, and tail rotor malfunction. Most American-built single-rotor helicopters turn the main rotor in a counterclockwise direction; therefore, the application of right pedal decreases pitch in the tail rotor and creates less thrust, allowing the nose of the aircraft to turn right. The opposite is true for application of left pedal.
扭矩效應。必須抵消扭矩以維持飛機的控制；反扭矩旋翼執行此任務（圖 1-44）。在串聯旋翼或同軸直升機中，兩個旋翼系統以相反方向旋轉，有效地抵消了扭矩效應。大多數旋翼機擁有單一主旋翼，並需要尾旋翼或其他手段來抵消扭矩效應。由於初始動作是由引擎功率（扭矩）驅動主旋翼系統產生的，因此這個扭矩必然會隨著施加的功率或執行的機動而變化。尾旋翼設計為可變螺距的反扭矩旋翼，以適應此類系統的變化效應。尾旋翼通常通過驅動軸安排由主傳動系統驅動，並位於尾桁的末端。驅動和控制尾旋翼所需的引擎功率可能相當可觀。飛行員在針對不同條件和情況進行性能規劃時必須考慮這一點。很容易理解為什麼會編寫各種緊急程序來補償如引擎功率喪失、引擎功率不足和尾旋翼故障等問題。 大多數美國製造的單旋翼直升機主旋翼以逆時針方向旋轉；因此，施加右踏板會降低尾旋翼的俯仰角並產生較少的推力，使飛機的機頭向右轉。施加左踏板則正好相反。
Figure 1-44. Torque reaction
圖 1-44. 扭矩反應
Heading Control
標題控制
1-91. Different helicopter designs such as single or dual-rotors use different mechanisms for heading control. There are many maneuvers that require precise heading control to avoid aircraft damage or injury to personnel. Aircrews should understand and anticipate forces that effect heading control for precise aircraft control.
1-91. 不同的直升機設計，如單旋翼或雙旋翼，使用不同的機制來控制航向。有許多操作需要精確的航向控制，以避免對飛機造成損壞或對人員造成傷害。機組人員應該理解並預測影響航向控制的力量，以實現精確的飛機控制。
Single-Rotor Helicopters
單旋翼直升機
1-92. In addition to counteracting torque, the tail rotor and its control linkage allow the aviator to control the helicopter heading during taxi, hover, and sideslip operations on takeoffs and approaches. Applying more pedal than needed to counteract torque causes the nose of the helicopter to swing in the direction of pedal movement (left pedal to the left). Applying less pedal than needed causes the helicopter to turn in the direction of torque (nose swings to the right). Aviators must use the antitorque pedals to maintain a constant heading at a hover or during a takeoff or an approach. They apply just enough pitch on the tail rotor to neutralize torque and to hold a slip.
1-92. 除了抵消扭矩外，尾旋翼及其控制連桿使飛行員能夠在滑行、懸停和側滑操作中控制直升機的航向。施加比所需更多的踏板以抵消扭矩會導致直升機的機頭朝踏板移動的方向擺動（左踏板向左）。施加比所需更少的踏板會導致直升機朝扭矩的方向轉向（機頭向右擺動）。飛行員必須使用抗扭踏板來保持懸停時或在起飛或進場時的恆定航向。他們在尾旋翼上施加足夠的俯仰以中和扭矩並保持側滑。
1-93. Heading control in forward trimmed flight is normally accomplished by cyclic control with a coordinated bank and turn to the desired heading. The antitorque pedal must be applied when power changes are made.
1-93. 在前方修剪飛行中，航向控制通常是通過循環控制來實現，並協調銀行和轉向到所需的航向。當進行功率變更時，必須踩下反扭矩踏板。
Tandem-Rotor Helicopters
串聯旋翼直升機
1-94. Heading control is accomplished in tandem-rotor helicopters by differential lateral tilting of the rotor disks. When the directional pedal (right or left) is applied, the forward rotor disk tilts in the same direction and the aft rotor disk tilts in the opposite direction. The result is a hovering turn around a vertical axis, midway between the rotors.
1-94. 在雙旋翼直升機中，航向控制是通過旋翼盤的側向差異傾斜來實現的。當方向踏板（右或左）被施加時，前旋翼盤向相同方向傾斜，而後旋翼盤則向相反方向傾斜。結果是在旋翼之間的垂直軸上進行懸停轉向。
1-95. Heading control in forward flight is accomplished by coordinated use of lateral cyclic tilt on both rotors for roll control and differential cyclic tilt on the rotors for yaw control. Only small changes in pedal trim are required for changes in longitudinal speed trim or during descents, climbs, and autorotations
1-95. 在前進飛行中，航向控制是通過協調使用兩個旋翼的側向循環傾斜來進行滾轉控制，以及旋翼的差異循環傾斜來進行偏航控制。對於縱向速度修整的變化或在下降、爬升和自轉降落期間，只需對踏板修整進行小幅度的調整。.
BALANCE OF FORCES
力量平衡
1-96. Newton’s law of acceleration states the force required to produce a change in motion of a body is directly proportional to its mass and rate of change in its velocity. This means motion is started, stopped, or changed when forces acting on the body become unbalanced. Rate of change (acceleration) depends on the magnitude of the unbalanced force and on the mass of the body to which it is applied. This principle is the basis for all helicopter flight—vertical, forward, rearward, sideward, or hovering. In each case, total force generated by a rotor system is always perpendicular to the tip-path plane (figure 1-45 through figure 1-48). For this discussion, this force is divided into two components: lift and thrust. The lift component supports aircraft weight while the thrust component acts horizontally to accelerate or decelerate the helicopter in the desired direction. Aviators direct thrust in a desired direction by tilting the tip-path plane. At a hover in a no-wind condition, all opposing forces are in balance; they are equal and opposite. Therefore, lift and weight are equal, resulting in the helicopter remaining stationary (figure 1-45).
1-96. 牛頓的加速度定律指出，產生物體運動變化所需的力量與其質量及速度變化率成正比。這意味著當作用於物體的力量變得不平衡時，運動會開始、停止或改變。變化率（加速度）取決於不平衡力量的大小以及施加於物體的質量。這一原則是所有直升機飛行的基礎——垂直、向前、向後、側向或懸停。在每種情況下，旋翼系統產生的總力量始終垂直於尖端路徑平面（圖 1-45 至圖 1-48）。在本討論中，這股力量被分為兩個組件：升力和推力。升力組件支撐飛機的重量，而推力組件則水平作用以加速或減速直升機朝所需方向。飛行員通過傾斜尖端路徑平面來引導推力朝所需方向。在無風條件下的懸停狀態下，所有對抗力量處於平衡狀態；它們是相等且相反的。因此，升力和重量相等，導致直升機保持靜止（圖 1-45）。
Figure 1-45. Balanced forces; hovering with no wind
圖 1-45. 平衡力；在無風狀態下懸停
1-97. To make the helicopter move in some direction, a force must be applied to cause an unbalanced condition. Figure 1-46, page 1-32, illustrates an unbalanced condition in which the aviator has changed the attitude of the rotor disk creating a lift and thrust vector, resulting in a total force forward of the vertical. No parasite drag is shown as the aircraft has not started to move forward.
1-97. 要使直升機朝某個方向移動，必須施加一個力以造成不平衡狀態。圖 1-46，頁 1-32，說明了一種不平衡狀態，其中飛行員改變了旋翼盤的姿態，產生了升力和推力向量，導致總力向前偏離垂直方向。由於飛機尚未開始向前移動，因此未顯示寄生阻力。
Figure 1-46. Unbalanced forces causing acceleration
圖 1-46. 不平衡的力量造成加速度
1-98. As the aircraft begins to accelerate in the direction of applied thrust, parasite drag develops. When parasite drag increases to be equal to thrust, the aircraft no longer accelerates because the forces are again in balance (figure 1-47) as the aircraft has achieved steady-state (unaccelerated) flight.
1-98. 當飛機開始朝施加推力的方向加速時，寄生阻力會產生。當寄生阻力增加到等於推力時，飛機不再加速，因為力量再次達到平衡（圖 1-47），飛機已達到穩態（不加速）飛行。
Figure 1-47. Balanced forces; steady-state flight
圖 1-47. 平衡力；穩態飛行
1-99. To return the aircraft to a hover, the aviator changes the disk attitude to unbalance the forces (figure 1- 48). By tilting the rotor disk aft, the thrust force acts in the same direction as parasite drag and airspeed decreases.
1-99. 為了將飛機恢復到懸停狀態，飛行員改變旋翼盤的姿態以不平衡各種力量（圖 1-48）。通過將旋翼盤向後傾斜，推力方向與寄生阻力相同，空速減少。
Figure 1-48. Unbalanced forces causing deceleration
圖 1-48. 不平衡的力量造成減速
1-100. Understanding hovering flight is critical for the safe operation of the aircraft. Aircraft weight, engine power parameters, and aerodynamic forces must be factored into pre-mission planning. Hover checks verify performance planning and ensure parameters are correct for the mission.
1-100. 理解懸停飛行對於安全操作飛機至關重要。飛機重量、引擎功率參數和空氣動力學力必須納入任務前的規劃中。懸停檢查驗證性能規劃並確保參數對於任務是正確的。
AIRFLOW IN HOVERING FLIGHT
懸停飛行中的氣流
1-101. An increase of blade pitch (through application of collective) that increases AOA, generates the additional lift necessary to hover (figure 1-49, page 1-33). For a helicopter to hover, lift produced by the rotor system must equal the total weight of the helicopter. In a no-wind condition, the tip-path plane remains horizontal. As forces of lift and weight are in balance during stationery hover, those forces must be altered— through application of collective—to either climb or descend vertically.
1-101. 增加葉片角度（透過集體控制的應用）會增加攻角，產生懸停所需的額外升力（圖 1-49，頁 1-33）。為了讓直升機懸停，旋翼系統產生的升力必須等於直升機的總重量。在無風條件下，尖端路徑平面保持水平。由於在靜止懸停時升力和重量的力量處於平衡狀態，這些力量必須透過集體控制的應用來改變，以便垂直上升或下降。
Figure 1-49. Airflow in hovering flight
圖 1-49. 懸停飛行中的氣流
1-102. At a hover, the rotor-tip vortex (air swirl at the tip of the rotor blades) reduces effectiveness of the outer blade portions. Vortices of the preceding blade affect the lift of any other blade in the rotor system. When maintaining a stationery hover, this continuous creation of vortices—combined with the ingestion of existing vortices—is the primary cause of high power requirements for hovering. Rotor-tip vortices are part of the induced flow and increase induced drag.
1-102. 在懸停時，旋翼尖渦（旋翼葉片尖端的氣流漩渦）降低了外部葉片部分的效能。前一葉片的渦流會影響旋翼系統中任何其他葉片的升力。在保持靜止懸停時，這種持續產生的渦流—加上對現有渦流的吸入—是懸停所需高功率的主要原因。旋翼尖渦是誘導流的一部分，並增加了誘導阻力。
1-103. During hover, rotor blades move large amounts of air through the rotor system in a downward direction. This movement of air also introduces another element—induced flow—into relative wind, which alters the AOA of the airfoil. If there is no induced flow, relative wind is opposite and parallel to the flight path of the airfoil. With a downward airflow altering the relative wind, the AOA is decreased so less aerodynamic force is produced. This change requires the aviator to increase collective pitch to produce enough aerodynamic force to hover.
1-103. 在懸停期間，旋翼葉片向下方移動大量空氣通過旋翼系統。這種空氣的運動還引入了另一個元素——誘導流——進入相對風，這改變了氣動翼的攻角。如果沒有誘導流，相對風將與氣動翼的飛行路徑相對且平行。隨著向下的氣流改變相對風，攻角減小，因此產生的氣動力也減少。這一變化要求飛行員增加總體桨距，以產生足夠的氣動力來懸停。
GROUND EFFECT
地面效應
1-104. The difference in rotor efficiency while operating in-ground effect versus out-of-ground effect is substantial. Knowing what affects the efficiency of the rotor system is foundational knowledge for a number of mission sets. Some mission parameters require the aerodynamic aid of ground effect for successful flight.
1-104. 在地面效應下與不在地面效應下運行時，轉子效率的差異是相當大的。了解影響轉子系統效率的因素是多個任務組合的基礎知識。一些任務參數需要地面效應的空氣動力學輔助才能成功飛行。
Ground Effect Efficiency
地面效應效率
1-105. Ground effect is the increased efficiency of the rotor system caused by interference of the airflow when near the ground. Ground effect permits relative wind to be more horizontal, lift vector to be more vertical, and induced drag to be reduced. These allow the rotor system to be more efficient. The aviator achieves maximum ground effect when hovering over smooth hard surfaces. When the aviator hovers over such terrain as tall grass, trees, bushes, rough terrain, and water, maximum ground effect is reduced. Two reasons for this phenomenon are induced flow and vortex generation.
1-105. 地面效應是指當接近地面時，因氣流干擾而導致的旋翼系統效率提高。地面效應使相對風更為水平，升力向量更為垂直，並減少誘導阻力。這些因素使旋翼系統的效率更高。飛行員在平滑堅硬的表面上懸停時達到最大地面效應。當飛行員在高草、樹木、灌木、崎嶇地形和水面等地形上懸停時，最大地面效應會減少。造成這一現象的兩個原因是誘導流和渦流生成。
Induced Flow
誘導流
1-106. Proximity of the helicopter to the ground interrupts airflow under the helicopter by altering the velocity of induced flow. Induced flow velocity is reduced when closer to the ground, which in turn, increases AOA, reduces the amount of induced drag, allows a more vertical lift vector, and increases rotor system efficiency.
1-106. 直升機靠近地面時會通過改變誘導流的速度來干擾直升機下方的氣流。當靠近地面時，誘導流速度會降低，這反過來增加了攻角，減少了誘導阻力，允許更垂直的升力向量，並提高了旋翼系統的效率。
Vortex Generation
漩渦生成
1-107. When operating close enough to a surface for ground effect to exist, the downward and outward flow of air tends to restrict vortex generation. The smaller vortexes result in the outboard portion of each blade
1-107. 當操作接近表面以至於存在地面效應時，向下和向外的氣流傾向於限制渦流的產生。較小的渦流導致每個葉片的外側部分
becoming more efficient and reduce overall system turbulence caused by ingestion and recirculation of the vortex pattern.
變得更有效率，並減少由於漩渦模式的攝取和再循環所造成的整體系統擾動。
Categories
類別
1-108. Ground effect is categorized in two ways—in ground effect (IGE) and out of ground effect (OGE). Both are critical elements on a rotary-wing performance planning card (PPC).
1-108. 地面效應分為兩種——地面效應（IGE）和非地面效應（OGE）。這兩者都是旋翼機性能規劃卡（PPC）中的關鍵要素。
In-Ground Effect
地面效應
1-109. Rotor efficiency is increased by ground effect to a height of about one rotor diameter (measured from the ground to the rotor disk) for most helicopters. Figure 1-50 shows IGE hover and induced flow reduced. This increase in AOA requires a reduced blade pitch angle. This reduces the power required to hover IGE.
1-109. 對於大多數直升機，轉子效率因地面效應而提高至約一個轉子直徑的高度（從地面到轉子盤測量）。圖 1-50 顯示了 IGE 懸停和誘導流減少。這一迎角的增加需要降低葉片的俯仰角。這減少了懸停 IGE 所需的功率。
Figure 1-50. In ground effect hover
圖 1-50. 地面效應懸停
Out-of-Ground Effect
地面效應外部
1-110. The benefit of placing the helicopter near the ground is lost above IGE altitude. Above this altitude, the power required to hover remains nearly constant, given similar conditions (such as wind). Figure 1-51, page 1- 35, shows OGE hover. Induced flow velocity is increased causing a decrease in AOA. A higher blade pitch angle is required to maintain the same AOA as in IGE hover. The increased pitch angle also creates more drag. More power to hover OGE than IGE is required by this increased pitch angle and drag.
1-110. 將直升機放置在接近地面的好處在 IGE 高度以上會消失。在這個高度以上，保持懸停所需的功率在相似條件下（如風）幾乎保持不變。圖 1-51，頁 1-35，顯示了 OGE 懸停。誘導流速增加，導致 AOA 減少。需要更高的葉片俯仰角以維持與 IGE 懸停相同的 AOA。增加的俯仰角也會產生更多的阻力。由於這個增加的俯仰角和阻力，懸停 OGE 所需的功率比 IGE 更高。
Figure 1-51. Out of ground effect hover
圖 1-51. 超出地面效應的懸停
TRANSLATING TENDENCY
翻譯趨勢
1-111. During hovering flight, the counterclockwise rotating, single-rotor helicopter has a tendency to drift laterally to the right. The translating tendency (figure 1-52, page 1-36) results from right lateral tail-rotor thrust exerted to compensate for main rotor torque (main rotor turning in a counterclockwise direction). The aviator must compensate for this right translating tendency of the helicopter by tilting the main rotor disk to the left. This lateral tilt creates a main rotor force to the left compensating for the tail-rotor thrust to the right. Helicopter design usually includes one or more of the following features, which help the aviator compensate for translating tendency:
1-111. 在懸停飛行期間，逆時針旋轉的單旋翼直升機有向右側漂移的傾向。這種平移傾向（圖 1-52，頁 1-36）是由於右側尾旋翼推力的作用，以補償主旋翼的扭矩（主旋翼以逆時針方向旋轉）。飛行員必須通過將主旋翼盤傾斜向左來補償直升機的右側平移傾向。這種側向傾斜產生向左的主旋翼力，以補償向右的尾旋翼推力。直升機設計通常包括以下一個或多個特徵，幫助飛行員補償平移傾向：
Flight control rigging may be designed so the rotor disk is tilted slightly left when the cyclic control is centered.
飛行控制裝置的調整可以設計成當循環控制居中時，旋翼盤略微向左傾斜。
Transmission may be mounted so the mast is tilted slightly left when the helicopter fuselage is laterally level.
傳動裝置可以安裝在直升機機身側向水平時，桅杆略微向左傾斜。
The collective pitch control system may be designed so the rotor disk tilts slightly left as collective pitch is increased.
集體變距控制系統可以設計成當集體變距增加時，轉子盤輕微向左傾斜。
Programmed mechanical inputs/automatic flight-control systems/stabilization augmentation systems.
程式化機械輸入/自動飛行控制系統/穩定性增強系統。
Figure 1-52. Translating tendency
圖 1-52. 翻譯傾向
1-112. Aircrews should strive to understand the relationship between their rotor systems and different stages of flight starting from a stagnant hover. Such knowledge becomes critical during limited power situations. Understanding the forces acting on the rotor system as it transitions from a hover allows the aviators to anticipate control inputs for precise aircraft handling.
1-112. 飛行員應努力了解其旋翼系統與不同飛行階段之間的關係，從靜止懸停開始。這種知識在有限功率情況下變得至關重要。了解旋翼系統在從懸停過渡時所受的力，使飛行員能夠預測控制輸入，以實現精確的飛機操控。
AIRFLOW IN FORWARD FLIGHT
前進飛行中的氣流
1-113. Airflow across the rotor system in forward flight varies from airflow at a hover. In forward flight, air flows opposite the aircraft’s flight path. The velocity of this air flow equals the helicopter’s forward speed. Because the blades turn in a circular pattern, the velocity of airflow across a blade depends on the position of the blade in the plane of rotation at a given instant, its rotational velocity, and airspeed of the helicopter. Therefore, the airflow meeting each blade varies continuously as the blade rotates. The highest velocity of airflow occurs over the right side (3 o’clock position) of the helicopter (advancing blade in a rotor system that turns counterclockwise) and decreases to rotational velocity over the nose. It continues to decrease until the lowest velocity of airflow occurs over the left side (9-o’clock position) of the helicopter (retreating blade). As the blade continues to rotate, velocity of the airflow then increases to rotational velocity over the tail. It continues to increase until the blade is back at the 3 o’clock position.
1-113. 在前進飛行中，旋翼系統的氣流與懸停時的氣流有所不同。在前進飛行中，氣流與飛機的飛行路徑相反。這股氣流的速度等於直升機的前進速度。由於葉片以圓形模式旋轉，氣流在某一瞬間穿過葉片的速度取決於葉片在旋轉平面中的位置、其旋轉速度以及直升機的空速。因此，迎接每片葉片的氣流隨著葉片的旋轉而不斷變化。氣流的最高速度出現在直升機的右側（3 點鐘位置）（在逆時針旋轉的旋翼系統中為前進葉片），並在機頭處減少至旋轉速度。它繼續減少，直到氣流的最低速度出現在直升機的左側（9 點鐘位置）（為後退葉片）。隨著葉片繼續旋轉，氣流的速度隨後在尾部增加至旋轉速度。它繼續增加，直到葉片回到 3 點鐘位置。
1-114. The advancing blade (figure 1-53, blade A, page 1-37) moves in the same direction as the helicopter. The velocity of the air meeting this blade equals rotational velocity of the blade plus wind velocity resulting from forward airspeed. The retreating blade (blade C) moves in a flow of air moving in the opposite direction of the helicopter. The velocity of airflow meeting this blade equals rotational velocity of the blade minus wind velocity resulting from forward airspeed. The blades (B and D) over the nose and tail move essentially at right angles to the airflow created by forward airspeed; the velocity of airflow meeting these blades equals the rotational velocity. This results in a change to velocity of airflow all across the rotor disk and a change to the lift pattern of the rotor system. Figure 1-54, page 1-38, depicts force vectors acting on various blade areas in forward flight.
1-114. 前進的葉片（圖 1-53，葉片 A，頁 1-37）與直升機的移動方向相同。迎面而來的空氣速度等於葉片的旋轉速度加上由前進空速產生的風速。後退的葉片（葉片 C）則在與直升機相反方向的氣流中移動。迎面而來的氣流速度等於葉片的旋轉速度減去由前進空速產生的風速。位於機頭和機尾的葉片（B 和 D）基本上與由前進空速產生的氣流成直角；迎面而來的氣流速度等於旋轉速度。這導致整個旋翼盤的氣流速度發生變化，並改變了旋翼系統的升力模式。圖 1-54，頁 1-38，描繪了在前進飛行中作用於各個葉片區域的力向量。
Figure 1-53. Differential velocities on the rotor system caused by forward airspeed
圖 1-53. 由於前進空速引起的轉子系統上的差異速度
No-Lift Areas
無升降區域
1-115. The no-lift areas are reverse flow, negative stall, and negative lift.
1-115. 無升力區域為逆流、負失速和負升力。
Reverse Flow
反向流動
1-116. Part A of figure 1-54, page 1-38, shows reverse flow. At the root of the retreating blade is an area where the air flows backward from the trailing to the leading edge of the blade. This is due to wind created by forward airspeed being greater than rotational velocity at this point on the blade.
1-116. 圖 1-54 的 A 部分，頁 1-38，顯示了逆流。在後退葉片的根部，有一個區域，空氣從葉片的尾緣流向前緣反向流動。這是因為在葉片的這一點，前進的空氣速度大於旋轉速度所產生的風。
Negative Stall
負面失速
1-117. Part B of figure 1-54 shows negative stall. In the negative stall area, rotational velocity exceeds forward flight velocity, causing resultant relative wind to move toward the leading edge. The resultant relative wind is so far above the chord line, a negative AOA above the critical AOA results. The blade stalls with a negative AOA.
1-117. 圖 1-54 的 B 部分顯示負失速。在負失速區域，旋轉速度超過前進飛行速度，導致合成相對風向前緣移動。合成相對風遠高於弦線，導致在臨界攻角之上出現負攻角。葉片在負攻角下失速。
Negative Lift
負升力
1-118. Part C of figure 1-54 shows negative lift. In the negative lift area, rotational velocity, induced flow, and blade flapping combine to reduce the AOA from a negative stall to an AOA that causes the blade to produce negative lift.
1-118. 圖 1-54 的 C 部分顯示負升力。在負升力區域，旋轉速度、誘導流和葉片擺動結合在一起，將攻角從負失速降低到導致葉片產生負升力的攻角。
Positive Lift and Positive Stall
正升力與正失速
1-119. Figure 1-54, parts D and E, show positive lift and positive stall. That portion of the blade outboard of the no-lift areas produces positive lift. In the positive lift area, the resultant relative wind produces a positive AOA. Under certain conditions, it is possible to have a positive stall area near the blade tip. Section VIII covers retreating blade stall.
1-119. 圖 1-54 的 D 和 E 部分顯示正升力和正失速。葉片外側的無升力區域產生正升力。在正升力區域，結果相對風產生正攻角。在某些條件下，葉片尖端附近可能會有正失速區域。第八節涵蓋後退葉片失速。
Figure 1-54. Blade areas in forward flight
圖 1-54. 向前飛行中的葉片面積
Dissymmetry of Lift
升力的不對稱性
1-120. Dissymmetry of lift is the unequal lift across the rotor disk resulting from the difference in the velocity of air over the advancing blade half and the velocity of air over the retreating blade half of the rotor disk area. (FAA-H-8083-21B) This difference in lift would cause the helicopter to be uncontrollable in any situation other than hovering in a calm wind. There must be a means of compensating, correcting, or eliminating this unequal lift to attain symmetry of lift.
1-120. 升力的不對稱是指由於旋翼盤面上前進葉片半部與後退葉片半部的氣流速度差異所造成的升力不均。 (FAA-H-8083-21B) 這種升力差異會使直升機在任何情況下都無法控制，除了在平靜的風中懸停。 必須有一種方法來補償、修正或消除這種不均勻的升力，以達到升力的對稱。
1-121. In forward flight, two factors in the lift equation, blade area and air density, are the same for the advancing and retreating blades. Airfoil shape is fixed for a given blade, and air density cannot be affected; the only remaining variables are blade speed and AOA. Rotor RPM controls blade speed. Because rotor RPM must remain relatively constant, blade speed also remains relatively constant. This leaves AOA as the one variable remaining that can compensate for dissymmetry of lift. This compensation is accomplished through a combination of or individually by blade flapping and cyclic feathering.
1-121。在前進飛行中，升力方程中的兩個因素，葉片面積和空氣密度，對於前進和後退的葉片是相同的。對於給定的葉片，翼型形狀是固定的，空氣密度也無法受到影響；唯一剩下的變數是葉片速度和攻角（AOA）。轉子轉速（RPM）控制葉片速度。由於轉子轉速必須保持相對穩定，葉片速度也保持相對穩定。這使得攻角成為唯一可以補償升力不對稱的變數。這種補償是通過葉片拍動和循環羽化的組合或單獨實現的。
Blade Flapping
刀片拍打
1-122. When blade flapping compensates for dissymmetry of lift, the upward and downward flapping motion changes induced flow velocity. This changes AOA on the advancing and retreating blades.
1-122. 當刀片拍動補償升力的不對稱時，向上和向下的拍動運動改變了誘導流速。這改變了前進和後退刀片的攻角。
Advancing Blade
進階刀刃
1-123. As the relative wind speed of the advancing blade increases, the blade gains lift and begins to flap up (figure 1-55). It reaches its maximum upflap velocity at the 3-o’clock position, where the wind velocity is the greatest. This upflap creates a downward flow of air and has the same effect as increasing the induced flow velocity by imposing a downward vertical velocity vector to the relative wind. This decreases the AOA.
1-123. 隨著前進葉片的相對風速增加，葉片獲得升力並開始向上拍動（圖 1-55）。在 3 點鐘位置，葉片達到其最大向上拍動速度，此時風速為最大。這種向上拍動產生了向下的氣流，並且具有通過對相對風施加向下的垂直速度向量來增加誘導流速的相同效果。這降低了攻角（AOA）。
Figure 1-55. Flapping (advancing blade, 3-o’clock position)
圖 1-55. 拍打（前進葉片，3 點鐘位置）
Retreating Blade
退刀
1-124. As relative wind speed of the retreating blade decreases, the blade loses lift and begins to flap down (figure 1-56). It reaches its maximum downflap velocity at the 9 o’clock position, where wind velocity is the least. This downflap creates an upward flow of air and has the same effect as decreasing the induced flow velocity by imposing an upward velocity vertical vector to the relative wind. This increases AOA.
1-124. 隨著退行葉片的相對風速減少，葉片失去升力並開始向下拍動（圖 1-56）。它在 9 點鐘位置達到最大下拍速度，此時風速最低。這種下拍產生了向上的氣流，並對相對風施加一個向上的速度垂直向量，具有減少誘導流速的相同效果。這增加了攻角（AOA）。
Figure 1-56. Flapping (retreating blade, 9-o’clock position)
圖 1-56. 拍打（後退葉片，9 點鐘位置）
Over the Aircraft Nose and Tail
飛機的機頭和機尾上
1-125. Blade flapping over the nose and tail of the helicopter are essentially equal. The net result is an equalization, or symmetry, of lift across the rotor system. Up flapping and down flapping do not change the total amount of lift produced by the rotor blades. When blade flapping has compensated for dissymmetry of lift, the rotor disk is tilted to the rear, called blowback. The maximum upflap occurring over the nose and the maximum downflap occurring over the tail cause blowback. This would cause airspeed to decrease. The aviator uses cyclic feathering to compensate for dissymmetry of lift allowing the aviator to control the attitude of the rotor disk.
1-125. 直升機的葉片在機頭和機尾的擺動基本上是相等的。最終結果是提升力在旋翼系統中達到均衡或對稱。向上擺動和向下擺動不會改變旋翼葉片產生的總提升力。當葉片擺動已經補償了提升力的不對稱時，旋翼盤會向後傾斜，稱為回流。發生在機頭的最大向上擺動和發生在機尾的最大向下擺動會導致回流。這會導致空速減少。飛行員使用循環羽化來補償提升力的不對稱，使飛行員能夠控制旋翼盤的姿態。
Cyclic Feathering
循環羽化
1-126. Cyclic feathering compensates for dissymmetry of lift (changes the AOA). At a hover, equal lift is produced around the rotor system with equal pitch and AOA on all the blades and at all points in the rotor system (disregarding compensation for translating tendency). The rotor disk is parallel to the horizon. To
1-126. 循環羽毛補償升力的不對稱（改變攻角）。在懸停時，旋翼系統周圍產生相等的升力，所有葉片的桨距和攻角相等，並且在旋翼系統的所有點上相等（不考慮平移趨勢的補償）。旋翼盤與地平線平行。
develop a thrust force, the rotor system must be tilted in the desired direction of movement. Cyclic feathering changes the angle of incidence differentially around the rotor system. Forward cyclic movements decrease the angle of incidence at one part on the rotor system while increasing the angle in another part. Maximum down flapping of the blade over the nose and maximum up flapping over the tail tilt the rotor disk and thrust vector forward. To prevent blowback from occurring, the aviator must continually move the cyclic forward as velocity of the helicopter increases. Figure 1-57 illustrates the changes in pitch angle as the cyclic is moved forward at increased airspeeds. At a hover, the cyclic is centered and the pitch angle on the advancing and retreating blades is the same. At low forward speeds, moving the cyclic forward reduces pitch angle on the advancing blade and increases pitch angle on the retreating blade. This causes a slight rotor tilt. At higher forward speeds, the aviator must continue to move the cyclic forward. This further reduces pitch angle on the advancing blade and further increases pitch angle on the retreating blade. As a result, there is even more tilt to the rotor than at lower speeds.
為了產生推力，轉子系統必須向所需的運動方向傾斜。循環羽化在轉子系統周圍差異性地改變迎角。向前的循環運動在轉子系統的一部分減少迎角，同時在另一部分增加迎角。刀片在機頭的最大向下拍打和在機尾的最大向上拍打使轉子盤傾斜並將推力向前。為了防止回流的發生，飛行員必須隨著直升機速度的增加不斷向前移動循環。圖 1-57 顯示了在增加空速時，循環向前移動時迎角的變化。在懸停時，循環處於中心位置，前進和後退刀片的迎角相同。在低前進速度下，向前移動循環會減少前進刀片的迎角並增加後退刀片的迎角。這會導致輕微的轉子傾斜。在較高的前進速度下，飛行員必須繼續向前移動循環。這進一步減少前進刀片的迎角並進一步增加後退刀片的迎角。 因此，轉子在較低速度下的傾斜程度更高。
Figure 1-57. Blade pitch angles
圖 1-57. 刀片角度
1-127. This horizontal lift component (thrust) generates higher helicopter airspeed. The higher airspeed induces blade flapping to maintain symmetry of lift. The combination of flapping and cyclic feathering maintains symmetry of lift and desired attitude on the rotor system and helicopter.
1-127. 這個水平升力元件（推力）產生更高的直升機空速。更高的空速引起葉片擺動以維持升力的對稱。擺動和循環調整的結合維持了升力的對稱和直升機旋翼系統及直升機的所需姿態。
Tandem-Rotor Helicopter Dissymmetry of Lift
串聯旋翼直升機升力不對稱
1-128. In tandem-rotor helicopters, the aviator does not manually compensate for dissymmetry of lift when applying forward cyclic. Automatic cyclic-feathering systems are installed on tandem-rotor helicopters. These systems are activated through computer-generated commands at specified airspeeds, usually starting around 70 knots. At low airspeeds, blade flapping compensates for dissymmetry of lift. As airspeed increases, these systems program allowing a more level fuselage attitude and reduce stresses on the rotor driving mechanisms. If the cyclic-feathering system fails to properly feather the rotor system at higher airspeeds, greater blade- flapping angles and nose-low flight attitudes occur and induce increased stresses on the rotor-driving mechanisms.
在串列旋翼直升機中，飛行員在施加前循環時不需要手動補償升力的不對稱性。自動循環羽化系統安裝在串列旋翼直升機上。這些系統通過計算機生成的命令在特定的空速下啟動，通常在約 70 節時開始。在低空速下，葉片擺動補償升力的不對稱性。隨著空速的增加，這些系統會編程以允許更平穩的機身姿態，並減少對旋翼驅動機構的壓力。如果循環羽化系統在較高空速下未能正確羽化旋翼系統，則會出現更大的葉片擺動角度和機頭向下的飛行姿態，並導致對旋翼驅動機構的壓力增加。
TRANSLATIONAL LIFT
轉換升力
1-129. Improved rotor efficiency resulting from directional flight is translational lift. The efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind. As the incoming wind enters the rotor system, turbulence and vortexes are left behind and the flow of air becomes more horizontal. In addition, the tail rotor becomes more aerodynamically efficient during the transition from hover to forward flight. As the tail rotor works in progressively less turbulent air, this improved efficiency produces more thrust, causing the nose of the aircraft to yaw left (with a main rotor turning counterclockwise) and forces the aviator to apply right pedal (decreasing the AOA in the tail rotor blades) in response.
1-129. 由於定向飛行而改善的轉子效率稱為平移升力。隨著每一節的水平移動或地面風所獲得的進風，懸停轉子系統的效率得以提升。當進風進入轉子系統時，湍流和渦流被留下，氣流變得更加水平。此外，尾轉子在從懸停過渡到前進飛行的過程中變得更加氣動效率。隨著尾轉子在逐漸減少的湍流空氣中運作，這種改善的效率產生了更多的推力，導致飛機的機頭向左偏航（主轉子逆時針旋轉），並迫使飛行員施加右踏板（減少尾轉子葉片的攻角）以作出反應。
1-130. Figure 1-58, page 1-41, shows the airflow pattern for 1 to 5 knots of forward airspeed. Note how the downwind vortex is beginning to dissipate and induced flow down through the rear of the rotor system is more horizontal.
1-130。圖 1-58，頁 1-41，顯示了 1 到 5 節的前進空速的氣流模式。注意下風向渦流開始消散，並且通過旋翼系統後部的誘導流更加水平。
Figure 1-58. Translational lift (1 to 5 knots)
圖 1-58. 平移升力（1 到 5 節）
1-131. Figure 1-59 shows the airflow pattern at a speed of 10 to 15 knots. At this increased airspeed, the airflow continues to become more horizontal. The leading edge of the downwash pattern is being overrun and is well back under the nose of the helicopter.
1-131. 圖 1-59 顯示了風速為 10 到 15 節時的氣流模式。在這一增強的空氣速度下，氣流持續變得更加水平。下洗氣流模式的前緣被超越，並且位於直升機鼻部的後方。
Figure 1-59. Translational lift (10 to 15 knots)
圖 1-59. 平移升力 (10 到 15 節)
TRANSVERSE FLOW EFFECT
橫向流動效應
1-132. In forward flight, air passing through the rear portion of the rotor disk has a greater downwash angle than air passing through the forward portion. This is due to the fact the greater the distance air flows over the rotor disk, the longer the disk has to work on it and the greater the deflection on the aft portion. Downward flow at the rear of the rotor disk causes a reduced AOA, resulting in less lift. The front portion of the disk produces an increased AOA and more lift because airflow is more horizontal. These differences in lift between the fore and aft portions of the rotor disk are called transverse flow effect (figure 1-60, page 1-42). This effect causes unequal drag in the fore and aft portions of the rotor disk and results in vibration easily recognizable by the aviator. It occurs between 10 and 20 knots. Transverse flow effect is most noticeable during takeoff and, to a lesser degree, during deceleration for landing. Gyroscopic precession causes the effects to be manifested 90 degrees in the direction of rotation, resulting in a right rolling motion.
1-132。在前進飛行中，通過旋翼盤後部的氣流下洗角度大於通過前部的氣流。這是因為氣流在旋翼盤上流動的距離越大，旋翼盤對其的作用時間越長，後部的偏轉也越大。旋翼盤後部的向下流動導致迎角減小，從而產生較少的升力。旋翼盤的前部因為氣流更為水平，產生較大的迎角和更多的升力。旋翼盤前後部分之間的升力差異稱為橫向流動效應（圖 1-60，第 1-42 頁）。這種效應導致旋翼盤前後部分的阻力不均，並產生飛行員易於識別的振動。它發生在 10 到 20 節之間。橫向流動效應在起飛時最為明顯，在減速降落時則程度較輕。陀螺進動使這些效應在旋轉方向上表現出 90 度，導致向右的滾轉運動。
Figure 1-60. Transverse flow effect
圖 1-60. 橫向流動效應
EFFECTIVE TRANSLATIONAL LIFT
有效的轉換升力
1-133. Effective translational lift (ETL) (figure 1-61) occurs with the helicopter at about 16 to 24 knots, when the rotor—depending on size, blade area, and RPM of the rotor system—completely outruns the recirculation of old vortexes and begins to work in relatively undisturbed air. The rotor no longer pumps the air in a circular pattern but continually flies into undisturbed air. The flow of air through the rotor system is more horizontal, therefore induced flow and induced drag are reduced. The AOA is subsequently increased, which makes the rotor system operate more efficiently. This increased efficiency continues with increased airspeed until the best climb airspeed is reached, when total drag is at its’ lowest point. Greater airspeeds result in lower efficiency due to increased parasite drag.
1-133. 有效的平移升力（ETL）（圖 1-61）發生在直升機以約 16 到 24 節的速度飛行時，當旋翼—根據大小、葉片面積和旋翼系統的轉速—完全超越舊渦流的再循環，並開始在相對不受干擾的空氣中工作。旋翼不再以圓形模式抽吸空氣，而是持續飛入不受干擾的空氣中。通過旋翼系統的氣流變得更加水平，因此誘導流和誘導阻力減少。攻角隨之增加，使旋翼系統運行得更有效率。這種效率的提高隨著空速的增加而持續，直到達到最佳爬升空速，此時總阻力處於最低點。更高的空速會導致效率降低，因為寄生阻力增加。
Figure 1-61. Effective translational lift
圖 1-61. 有效的平移升力
1-134. As single-rotor aircraft speed increases, translational lift becomes more effective, nose rises or pitches up, and aircraft rolls to the right. The combined effects of dissymmetry of lift, gyroscopic precession, and transverse flow effect cause this tendency. Aviators must correct with additional forward and left lateral cyclic input to maintain a constant rotor-disk attitude.
1-134. 隨著單旋翼飛機速度的增加，平移升力變得更加有效，機頭上升或向上俯仰，飛機向右滾轉。升力的不對稱、陀螺進動和橫向流動效應的綜合作用導致了這一趨勢。飛行員必須通過額外的前進和左側橫向循環輸入來維持恆定的旋翼盤姿態。
AUTOROTATION
自動旋轉
1-135. In an emergency that results in an autorotation, the crew must work together as quickly as possible to prevent rotor decay beyond recoverable limits. The following section details the aerodynamics at work during an autorotational descent and landing.
1-135. 在導致自動旋轉的緊急情況下，機組人員必須儘快協同工作，以防止轉子衰退超過可恢復的極限。以下部分詳細說明自動旋轉下降和著陸過程中的空氣動力學。
Aerodynamics of Vertical Autorotation
垂直自轉的空氣動力學
1-136. During powered flight, rotor drag is overcome with engine power. When the engine fails or is deliberately disengaged from the rotor system, some other force must sustain rotor RPM so controlled flight can be continued to the ground. Adjusting the collective pitch to allow a controlled descent generates this force. Airflow during helicopter descent provides energy to overcome blade drag and turn the rotor. When the helicopter descends in this manner, it is in a state of autorotation. In effect, the aviator exchanges altitude at a controlled rate in return for energy to turn the rotor at a RPM that provides aircraft control and a safe landing. Helicopters have potential energy based on their altitude above the ground. As this altitude decreases, potential energy is converted into kinetic energy used in turning the rotor. Aviators use this kinetic energy to slow the rate of descent to a controlled rate and affect a smooth touchdown.
1-136. 在動力飛行期間，旋翼阻力是由引擎功率克服的。當引擎失效或故意與旋翼系統脫離時，必須有其他力量來維持旋翼轉速，以便能夠控制飛行降落。調整集體桨距以允許受控下降會產生這種力量。直升機下降過程中的氣流提供能量以克服葉片阻力並轉動旋翼。當直升機以這種方式下降時，它處於自轉狀態。實際上，飛行員以受控的速率交換高度，以換取能量來以提供飛機控制和安全著陸的轉速轉動旋翼。直升機的潛在能量基於其距地面的高度。隨著這一高度的降低，潛在能量轉化為用於轉動旋翼的動能。飛行員利用這種動能來減慢下降速率至受控速率，並實現平穩著陸。
1-137. Most autorotations are performed with forward airspeed. For simplicity, the following aerodynamic explanation is based on a vertical autorotative descent (no forward airspeed) in still air. Under these conditions, forces that cause the blades to turn are similar for all blades, regardless of their position in the plane of rotation. Therefore, dissymmetry of lift resulting from helicopter airspeed is not a factor. During autorotation, the rotor disk is divided into three regions—driven, driving, and stall (figure 1-62).
1-137. 大多數自轉降落是以前進空速進行的。為了簡化，以下的空氣動力學解釋基於靜止空氣中的垂直自轉下降（無前進空速）。在這些條件下，導致葉片轉動的力量對所有葉片都是相似的，無論它們在旋轉平面中的位置如何。因此，來自直升機空速的升力不對稱並不是一個因素。在自轉過程中，旋翼盤被劃分為三個區域——驅動區、驅動中區和失速區（圖 1-62）。
Figure 1-62. Blade regions in vertical autorotation descent
圖 1-62. 垂直自轉降落中的葉片區域
Driven Region
驅動區域
1-138. This region is also called the propeller region and nearest the blade tip. It normally consists of nearly 30 percent of the disk radius. In the driven region, the TAF acts above the blade and behind the axis of rotation. This region creates lift, which slows the rate of descent and drag, which slows rotation of the blade. Region size varies with the blade pitch setting, rate of descent, and rotor RPM. Any change of these factors also changes the size of the regions along the blade span.
1-138. 這個區域也被稱為螺旋槳區域，最接近葉片尖端。它通常佔整個圓盤半徑的近 30%。在驅動區域，TAF 作用於葉片上方和旋轉軸的後方。這個區域產生升力，減緩下降速度，並產生阻力，減緩葉片的旋轉。區域大小隨著葉片的俯仰設定、下降速度和轉子 RPM 而變化。這些因素的任何變化也會改變沿葉片跨度的區域大小。
Driving Region
駕駛區域
1-139. This region extends from about the 25 to 70 percent radius of the blade. It lies between the driven and stall regions. It can also be identified as the area of autorotative force because it is the region of the blade that produces the force necessary to turn the blades during autorotation. TAF in the driving region is inclined slightly forward of the axis of rotation and produces a continual acceleration force. This direction of force supplies thrust, which tends to accelerate the rotation of the blade. The size of the region varies with the blade pitch setting, rate of descent, and rotor RPM. Any change of these factors also changes the size of the regions along the blade span.
1-139. 此區域從約 25%到 70%刀片半徑延伸。它位於驅動區和失速區之間。它也可以被識別為自旋力區域，因為它是刀片產生在自旋過程中轉動刀片所需力量的區域。驅動區的 TAF 略微向前傾斜於旋轉軸，並產生持續的加速力量。這種力量的方向提供推進，傾向於加速刀片的旋轉。該區域的大小隨著刀片俯仰設定、下降速率和轉子 RPM 而變化。這些因素的任何變化也會改變刀片跨度沿線的區域大小。
Stall Region
停滯區域
1-140. This region includes the inboard 25 percent of the blade radius. It operates above the stall AOA and causes drag, which tends to slow the rotation of the blade.
1-140。此區域包括葉片半徑的內部 25%。它在失速攻角以上運行，並產生阻力，這會減慢葉片的旋轉。
Blade Region Relationships
刀片區域關係
1-141. Figure 1-63, page 1-45, illustrates the three regions. Additional information in the figure pertains to force vectors on those regions and two additional equilibrium points. This figure serves to locate those regions/points on the blade span and depict the interplay of force vectors. Force vectors are different in each region because rotational relative wind is slower near the blade root and increases continually toward the blade tip. In addition, blade twist gives a more positive AOA in the driving region than in the driven region. The combination of inflow up through the rotor with rotational relative wind produces different combinations of aerodynamic force at every point along the blade.
1-141. 圖 1-63，頁 1-45，說明了三個區域。圖中的附加信息涉及這些區域的力向量和兩個額外的平衡點。此圖用於定位葉片跨度上的這些區域/點並描繪力向量的相互作用。由於旋轉相對風在葉片根部較慢，並且向葉片尖端不斷增加，因此每個區域的力向量不同。此外，葉片扭轉使驅動區的攻角比驅動區更為正向。通過轉子進入的氣流與旋轉相對風的結合，在葉片的每一點產生不同的氣動力組合。
1-142. There are two points of equilibrium on the blade (figure 1-63, page 1-45)—point B, between the driven and driving regions, and point D, between the driving and stall regions. At this point, TAF is aligned with the axis of rotation. Lift and drag are produced, but overall, there is neither acceleration nor deceleration force developed.
1-142. 刀片上有兩個平衡點（圖 1-63，頁 1-45）—點 B，在驅動區和被驅動區之間，以及點 D，在驅動區和失速區之間。在這一點上，TAF 與旋轉軸對齊。產生升力和阻力，但總體上，沒有產生加速或減速力。
1-143. The aviator manipulates these regions to control all aspects of the autorotative descent. For example, if the collective pitch is increased, the pitch angle increases in all regions. This causes point of equilibrium B to move inboard and point of equilibrium D to move outboard along the blade span, thus increasing the size of the driven and stall regions while reducing the driving region. The stall region also becomes larger while the driving region is reduced in size. Reducing the size of the driving region decreases acceleration force and rotor RPM. An aviator can achieve a constant rotor RPM by adjusting the collective pitch so blade acceleration forces from the driving region are balanced with deceleration forces from the driven and stall regions.
1-143. 飛行員操控這些區域以控制自轉下降的所有方面。例如，如果集體桨距增加，所有區域的桨角也會增加。這會導致平衡點 B 向內移動，平衡點 D 沿著葉片跨度向外移動，從而增加驅動區和失速區的大小，同時減少驅動區的大小。失速區的大小也會變大，而驅動區的大小則減少。減少驅動區的大小會降低加速度和轉子轉速。飛行員可以通過調整集體桨距來實現恆定的轉子轉速，使驅動區的葉片加速度力與失速區和驅動區的減速力達到平衡。
Aerodynamics of Autorotation in Forward Flight
前飛行中的自轉氣動力學
1-144. Aerodynamic forces in forward flight (figure 1-64, page 1-46) are produced in exactly the same manner as in vertical autorotation. However, because forward speed changes the inflow of air up through the rotor disk, this changes the location and size of the regions on the retreating and advancing sides of the rotor disk. Because the retreating side experiences an increased AOA, all three regions move outboard along the blade span with the stall region growing larger and an area nearest the hub experiencing a reversed flow. Because the advancing side experiences a decreased AOA, the driven region takes up more of that blade span.
1-144. 向前飛行中的空氣動力學力（圖 1-64，第 1-46 頁）以與垂直自轉相同的方式產生。然而，由於向前速度改變了空氣通過旋翼盤的進氣，這改變了旋翼盤退行側和進行側區域的位置和大小。由於退行側經歷了增加的攻角，所有三個區域沿著葉片跨度向外移動，失速區域變得更大，靠近樞軸的區域經歷了反向流動。由於進行側經歷了減少的攻角，驅動區域佔據了更多的葉片跨度。
Figure 1-63. Force vectors in vertical autorotative descent
圖 1-63. 垂直自轉降落中的力向量
Figure 1-64. Autorotative regions in forward flight
圖 1-64. 前進飛行中的自轉區域
Autorotative Phases
自動旋轉階段
1-145. Autorotations may be divided into three distinct phases—entry, steady-state descent, and deceleration and touchdown. Each phase is aerodynamically different from the others.
1-145. 自動旋轉可分為三個明確的階段—進入、穩定下降和減速著陸。每個階段在空氣動力學上與其他階段有所不同。
Entry
條目
1-146. This phase is entered after loss of engine power. The loss of engine power and rotor RPM is more pronounced when the helicopter is at high gross weight, high forward speed, or in high-density altitude conditions. Any of these conditions demand increased power (high collective position) and a more abrupt reaction to loss of that power. In most helicopters, it takes only seconds for RPM decay to fall into a minimum safe range requiring a quick collective response from the aviator. Entry is a combination of figures 1-65 and 1- 66.
1-146. 當引擎失去動力後進入此階段。當直升機處於高總重、高前進速度或高密度高度條件下，動力和轉子轉速的損失會更加明顯。這些條件中的任何一種都需要增加動力（高集體位置）並對動力損失做出更迅速的反應。在大多數直升機中，轉速衰減到最低安全範圍只需幾秒鐘，這需要飛行員迅速做出集體反應。進入此階段是圖 1-65 和 1-66 的組合。
Level-Powered Flight at High Speed
平穩高速飛行
1-147. Figure 1-65 shows the airflow and force vectors for a blade in this configuration. Lift and drag vectors are large, and the TAF is inclined well to the rear of the axis of rotation. An engine failure in this mode will cause rapid rotor RPM decay. To prevent this, an aviator must lower the collective quickly, reducing drag, and inclining the TAF vector forward, nearer the axis of rotation.
1-147. 圖 1-65 顯示了在此配置下葉片的氣流和力向量。升力和阻力向量較大，TAF 相對於旋轉軸的傾斜角度較大。在此模式下發生引擎故障將導致轉子 RPM 快速衰減。為了防止這種情況，飛行員必須迅速降低集體油門，減少阻力，並將 TAF 向量向前傾斜，靠近旋轉軸。
Figure 1-65. Force vectors in level-powered flight at high speed
圖 1-65. 高速水平飛行中的力向量
Collective Pitch Reduction
集體變距減少
1-148. Figure 1-66, page 1-47, shows airflow and force vectors for a blade immediately after power loss and subsequent collective reduction, yet before the aircraft has begun to descend. Lift and drag are reduced, with the TAF vector inclined further forward than it is in powered flight. As the helicopter begins to descend, the
1-148。圖 1-66，頁 1-47，顯示了在失去動力和隨後的集體減少後，葉片的氣流和力向量，但在飛機開始下降之前。升力和阻力減少，TAF 向量比在有動力飛行時更向前傾斜。隨著直升機開始下降，
airflow begins to flow upward and under the rotor system. This causes the TAF to incline further forward until it reaches an equilibrium that maintains a safe operating RPM.
氣流開始向上流動並進入轉子系統。這使得 TAF 進一步向前傾斜，直到達到一個維持安全運行 RPM 的平衡。
Figure 1-66. Force vectors after power loss–reduced collective
圖 1-66. 功率損失後的力向量–減少的集體
Steady-State Descent
穩態下降
1-149. Figure 1-67 shows airflow and force vectors for a blade in steady-state autorotative descent. Airflow is now upward through the rotor disk because of the descent. This inflow of air creates a larger AOA although blade pitch angle has not changed since the descent began. TAF on the blade is increased and inclined further forward until equilibrium is established, rate of descent and rotor RPM are stabilized, and the helicopter is descending at a constant angle. Angle of descent is normally 17 to 20 degrees, depending on airspeed, density altitude, wind, and type of helicopter.
1-149. 圖 1-67 顯示了在穩態自轉下降中，葉片的氣流和力向量。由於下降，氣流現在是向上通過轉子盤。這股氣流的進入產生了更大的攻角，儘管自下降開始以來，葉片的俯仰角並未改變。葉片上的總攻角（TAF）增加並進一步向前傾斜，直到達到平衡，下降速率和轉子轉速穩定，直升機以恆定角度下降。下降角通常為 17 到 20 度，具體取決於空速、密度高度、風速和直升機類型。
Figure 1-67. Force vectors in autorotative steady-state descent
圖 1-67. 自轉穩態下降中的力向量
Deceleration and Touchdown
減速與著陸
1-150. Figure 1-68, page 1-48, shows airflow and force vectors for a blade in autorotative deceleration. To make an autorotative landing, aviators reduce airspeed and rate of descent just before touchdown. They can partially accomplish both actions by applying aft cyclic, which changes the attitude of the rotor disk in relation to the relative wind. This attitude change inclines the resultant lift of the rotor system to the rear, slowing forward speed. It also increases AOA on all blades by changing direction of airflow through the rotor system, thereby increasing rotor RPM. The lifting force of the rotor system is increased and rate of descent is reduced. After an aviator reduces forward speed to a safe landing speed, the helicopter is placed in a landing attitude while applying collective pitch to cushion the touchdown.
1-150。圖 1-68，頁 1-48，顯示了在自旋減速中，葉片的氣流和力向量。為了進行自旋著陸，飛行員在觸地前減少空速和下降率。他們可以通過施加後循環部分實現這兩個動作，這會改變旋翼盤相對於相對風的姿態。這種姿態變化使旋翼系統的合成升力向後傾斜，減慢前進速度。它還通過改變氣流方向來增加所有葉片的攻角，從而提高旋翼轉速。旋翼系統的升力增強，下降率減少。在飛行員將前進速度減少到安全著陸速度後，直升機被置於著陸姿態，同時施加集體桨距以緩衝觸地。
Figure 1-68. Autorotative deceleration
圖 1-68. 自動旋轉減速
Glide and Rate of Descent in Autorotation
自動旋轉中的滑行與下降速率
1-151. Helicopter airspeed and drag are significant factors affecting rate of descent in autorotation. The rate of descent is high at very low airspeeds, decreases to a minimum at some intermediate speed and increases again at faster speeds. Airspeeds for minimum rate of descent and maximum glide distance vary by helicopter type and can be found in individual operator manuals (figure 1-69, page 1-49).
1-151. 直升機的空速和阻力是影響自轉下降率的重要因素。在非常低的空速下，下降率很高，隨著空速增加在某個中間速度時下降率降至最低，然後在更快的速度下再次增加。最低下降率和最大滑行距離的空速因直升機類型而異，具體數據可在各個操作手冊中找到（圖 1-69，第 1-49 頁）。
Circle of Action
行動圈
1-152. The circle of action is a point on the ground that has no apparent movement in the pilot's field of view (FOV) during a steady-state autorotation. The circle of action would be the point of impact if the pilot applied no deceleration, initial pitch, or cushioning pitch during the last 100 feet of autorotation. Depending on the amount of wind present and the rate and amount of deceleration and collective application, the circle of action is usually two or three helicopter lengths short of the touchdown point.
1-152. 行動圓是一個在穩態自轉過程中，飛行員視野（FOV）中沒有明顯運動的地面點。如果飛行員在自轉的最後 100 英尺內不施加減速、初始俯仰或緩衝俯仰，行動圓將是撞擊點。根據風的強度以及減速和集體操作的速率和程度，行動圓通常距離著陸點兩到三架直升機的長度。
Last 50 to 100 Feet
最後 50 到 100 英尺
1-153. It can be assumed autorotation ends at 50 to 100 feet and landing procedures then begin. To execute a power-off landing for rotary-wing aircraft, an aviator exchanges airspeed for lift by decelerating the aircraft during the last 100 feet. When executed correctly, deceleration is applied and timed so rate of descent and forward airspeed are minimized just before touchdown. At about 10 to 15 feet, this energy exchange is essentially complete. Initial pitch application occurs at 10 to 15 feet. This is used to trade some of the rotor energy to slow the rate of descent prior to cushioning. The primary remaining control input is application of collective pitch to cushion touchdown. Because all helicopter types are slightly different, aviator experience in that particular aircraft is the most useful tool for predicting useful energy exchange available at 100 feet and the appropriate amount of deceleration and collective pitch needed to execute the exchange safely and land successfully.
1-153. 可以假設自動旋轉在 50 到 100 英尺時結束，然後開始著陸程序。為了執行旋翼機的無動力著陸，飛行員在最後 100 英尺內通過減速來交換空速以獲取升力。當正確執行時，減速的應用和時機安排使得下降率和前進空速在觸地前達到最小化。在約 10 到 15 英尺時，這種能量交換基本完成。初始的俯仰應用發生在 10 到 15 英尺時。這用於在緩衝之前交易一些旋翼能量以減慢下降率。主要剩餘的控制輸入是應用集體俯仰以緩衝著陸。由於所有直升機類型略有不同，飛行員在特定飛機上的經驗是預測在 100 英尺時可用的有效能量交換以及執行安全交換和成功著陸所需的適當減速和集體俯仰的最有用工具。
Figure 1-69. Drag and airspeed relationship
圖 1-69. 拖曳與空速關係
1-154. During maneuvering flight, a considerable amount of information is processed. Aircrews must be familiar with power margins, possible maneuvers to be performed, and escape plans. Mission rehearsals and continuous crew coordination allows the aircrew to anticipate maneuvers and decrease reaction time for unplanned events.
1-154. 在機動飛行期間，處理了大量信息。機組人員必須熟悉功率邊際、可能執行的機動以及逃生計劃。任務排練和持續的機組協調使機組人員能夠預測機動並減少對突發事件的反應時間。
AERODYNAMICS
空氣動力學
1-155. There are several characteristics aviators must be aware of to successfully perform combat maneuvers.
1-155. 飛行員必須了解幾個特徵，以成功執行戰鬥機動。
Best Rate-of-Climb/Maximum Endurance Airspeed
最佳爬升率/最大耐力空速
1-156. This airspeed has the following characteristics—
1-156. 此空速具有以下特徵—
Total drag at the minimum.
最小時的總阻力。
Largest amount of excess power available.
可用的最大過剩電力。
Lowest fuel flow during powered flight.
在動力飛行期間的最低燃料流量。
Maximum single engine gross weight that can be carried (for dual engine aircraft).
可攜帶的最大單引擎總重量（適用於雙引擎飛機）。
1-157. Aviators should always be aware of their best rate-of-climb airspeed as it is where the aircraft will turn and climb the best, maximize available power margin, and get the lowest fuel flow.
1-157. 飛行員應始終注意其最佳爬升速度，因為這是飛機轉向和爬升的最佳時機，能最大化可用的功率裕度，並獲得最低的燃油流量。
Bucket Speed
桶速度
1-158. Bucket speed is the airspeed range providing the best power margin for maneuvering flight. Using the cruise chart for current conditions, enter at 50 percent of maximum torque available, go up to gross weight, over to the lowest and highest airspeed intersecting the aircraft gross weight, and note speeds between which there is the greatest power margin for maneuvering flight. The most critical is lower speed since at higher speeds airspeed energy may be traded to maintain altitude while maneuvering. When below minimum bucket speed reduce bank angle. Otherwise, altitude loss may become unavoidable.
1-158. 桶速是提供最佳動力邊際以進行機動飛行的空速範圍。使用當前條件的巡航圖，從最大扭矩的 50%進入，達到總重量，然後轉到與飛機總重量相交的最低和最高空速，並注意在這些速度之間的機動飛行最佳動力邊際。最關鍵的是較低的速度，因為在較高的速度下，空速能量可以用來在機動時維持高度。當低於最低桶速時，減少傾斜角度。否則，高度損失可能變得不可避免。
Transient Torque
瞬態扭矩
1-159. Transient torque is a phenomenon occurring in single-rotor helicopters when lateral cyclic is applied and is caused by aerodynamic forces. For conventional American helicopters where the main rotor turns counterclockwise, (figure 1-70) a left cyclic input causes a temporary rise in torque and a right cyclic input causes a temporary drop in torque.
1-159. 瞬時扭矩是單旋翼直升機在施加側向循環時發生的現象，並由氣動力作用引起。對於主旋翼逆時針旋轉的傳統美國直升機（圖 1-70），左側循環輸入會導致扭矩暫時上升，而右側循環輸入則會導致扭矩暫時下降。
Figure 1-70. Counterclockwise blade rotation
圖 1-70. 逆時針葉片旋轉
1-160. At the rear half of the rotor disk, downwash is greater than seen at the forward half of the rotor disk. This effect is more pronounced for heavier aircraft which exhibit greater coning due to their weight, causing even greater downwash at the rear of the rotor disk. If a left cyclic input is made by the pilot, the following events occur leading to a temporary increase in torque:
1-160. 在旋翼盤的後半部，向下氣流比在旋翼盤的前半部更強。這種效應在較重的飛機上更為明顯，因為它們因重量而顯示出更大的圓錐形，導致旋翼盤後部的向下氣流更強。如果飛行員施加左側循環輸入，則會發生以下事件，導致扭矩的暫時增加：
The swashplate commands an increased blade AOA as each blade passes over the tail.
擺盤在每片葉片經過尾部時指揮增加的葉片攻角。
The increase in blade AOA causes the rotor disk to tilt left, which is felt as a left roll on the aircraft.
葉片攻角的增加導致旋翼盤向左傾斜，這在飛機上感受到的是左側翻轉。
With increased lift on the rotor blades passing over the tail, there is also increased drag (induced drag).
隨著旋翼葉片在尾部上方產生的升力增加，阻力（誘導阻力）也隨之增加。
The increased rotor drag due to the left turn will initially try to slow the rotor, but is sensed by the applicable engine computer. The engine responds by delivering more torque to the rotor system to maintain rotor speed.
由於左轉而增加的轉子阻力最初會試圖減慢轉子，但會被相關的引擎電腦感知。引擎通過向轉子系統提供更多扭矩來響應，以維持轉子速度。
1-161. The opposite holds true for right cyclic turns, but is less pronounced. Unlike the left hand turn, in right turns blade pitch is being changed at the front of the rotor disk where induced downwash is lower, so the drag penalty is lower. Transient torque is not as prevalent at slower airspeeds because the induced downwash distribution is nearly uniform across the rotor disk.
1-161. 右旋轉的情況則相反，但不那麼明顯。與左轉不同，在右轉時，葉片的俯仰角在旋翼盤的前方進行變更，此處的誘導下洗較低，因此阻力懲罰較低。在較慢的空速下，瞬態扭矩不那麼明顯，因為誘導下洗的分佈在旋翼盤上幾乎是均勻的。
1-162. Five factors affect how much torque change occurs during transient torque—
1-162. 五個因素影響瞬態扭矩變化的程度—
Torque transients are proportional with the amount of power applied. The higher the torque setting when lateral cyclic inputs are made, the higher or lower the transient.
扭矩瞬態與施加的功率量成正比。當進行橫向循環輸入時，扭矩設置越高，瞬態就越高或越低。
Rate of movement of the cyclic. The faster the rate of movement the higher resultant torque spike.
循環的運動速率。運動速率越快，產生的扭矩峰值越高。
Magnitude of cyclic displacement directly affects the torque transient. An example of worst-case scenario occurs when a pilot initiates a rapid right roll, then due to an unexpected event breaks left. The transition from right cyclic applied to left cyclic applied results in a large amount of pitch change in the advancing blade, resulting in large torque transients.
循環位移的大小直接影響扭矩瞬態。最壞情況的例子發生在飛行員快速向右翻滾後，因意外事件向左打破。從施加右循環到施加左循環的過渡導致前進葉片的俯仰變化量大，從而產生大的扭矩瞬態。
Drag is increased or decreased by the factor of velocity squared. Thus, the higher the forward airspeed, the higher the torque transient results.
阻力隨速度平方的因子增加或減少。因此，前進空速越高，扭矩瞬態結果越高。
High aircraft weight increases coning, which makes transient torque more pronounced.
高飛機重量增加了錐度，這使得瞬時扭矩更加明顯。
1-163. Extreme caution must be used when maneuvering at near maximum torque available especially at high airspeeds. It is not uncommon to experience as much as 50 percent torque changes in uncompensated maneuvers with high power settings at high forward airspeeds. In these situations, the pilot must ensure collective is reduced as left lateral cyclic is applied and increased for right cyclic inputs. When recovering from these inputs, opposite collective inputs must be made so aircraft limitations are not exceeded.
1-163. 在接近最大可用扭矩時，尤其是在高空速下進行操作時，必須格外小心。在高前進空速下，使用高功率設置進行不補償的操作時，經常會經歷高達 50%的扭矩變化。在這些情況下，飛行員必須確保在施加左側橫向操縱時減少集體，並在施加右側操縱時增加集體。在從這些輸入中恢復時，必須進行相反的集體輸入，以免超出飛機的限制。
1-164. As a good basic technique, imagine a piece of string tied between the cyclic and collective (right cyclic- collective increase/left cyclic-collective decrease). Also, inputs must be made to keep the aircraft from descending due to torque reductions (when recovering from left cyclic inputs with collective reduced).
1-164. 作為一項良好的基本技術，想像一根繩子綁在循環桿和集體桿之間（右循環-集體增加/左循環-集體減少）。此外，必須進行輸入以防止因扭矩減少而使飛機下降（當從左循環輸入恢復時，集體桿減少）。
Note. 701C/D/DD/E equipped helicopters employ maximum torque rate attenuator which attempts to prevent transient torque related over-torques but may produce a rotor droop and loss of roll rate. Once the pilot has gained confidence in the ability of the maximum torque rate attenuator to prevent over-torques resulting from transient torque, aviators can aggressively maneuver the aircraft without closely monitoring engine torque.
注意。701C/D/DD/E 裝備的直升機使用最大扭矩速率減震器，該裝置旨在防止與瞬時扭矩相關的過扭矩，但可能會導致旋翼下垂和滾轉速率損失。一旦飛行員對最大扭矩速率減震器防止由瞬時扭矩引起的過扭矩的能力建立了信心，飛行員可以在不密切監控引擎扭矩的情況下積極操控飛機。
Mushing
拉雪橇
1-165. Mushing is a temporary stall condition occurring in helicopters when rapid aft cyclic is applied at high forward airspeeds. Normally associated with dive recoveries, which result in a significant loss of altitude, this phenomenon can also occur in a steep turn resulting in an increased turn radius. Mushing results during high G- maneuvers when at high forward airspeeds aft cyclic is abruptly applied. This results in a change in the airflow pattern on the rotor exacerbated by total lift area reduction as a result of rotor disc coning. Instead of an induced flow down through the rotor system, an upflow is introduced which results in a stall condition on portions of the entire rotor system. While this is a temporary condition (because in due time the upflow will dissipate and the stall will abate), the situation may become critical during low altitude recoveries or when maneuvering engagements require precise, tight turning radii. High aircraft gross weight and high density altitude are conditions conducive to and can aggravate mushing.
1-165. 冒險是一種在直升機中發生的暫時失速狀態，當在高前速下快速施加後循環時會出現。通常與俯衝恢復相關，這會導致顯著的高度損失，這一現象也可能在急轉彎中發生，導致轉彎半徑增加。當在高前速下突然施加後循環時，冒險會在高 G 操作中發生。這會導致旋翼系統的氣流模式發生變化，並因旋翼盤的圓錐效應而減少總升力面積。取而代之的是，氣流向上流動，這導致整個旋翼系統的部分區域出現失速狀態。雖然這是一種暫時狀態（因為隨著時間的推移，上升氣流會消散，失速會減輕），但在低高度恢復或當機動操作需要精確、緊湊的轉彎半徑時，情況可能變得危急。高飛機總重和高密度高度是有利於並可能加劇冒險的條件。
1-166. Mushing can be recognized by the aircraft failing to respond immediately but continuing on the same flight path as before the application of aft cyclic. Slight feedback and mushiness may be felt in the controls. When mushing occurs, the tendency is to pull more aft cyclic which prolongs stall and increases recovery times. Make a forward cyclic adjustment to recover from the mushing condition. This reduces the induced flow, improves the resultant AOA, and reduces rotor disc coning which increases the total lift area of the disc. The pilot will immediately feel a change in direction of the aircraft and increased forward momentum as the cyclic
1-166. 垂直失速可以通過飛機未能立即響應但繼續沿著與施加後循環前相同的飛行路徑來識別。控制器中可能會感覺到輕微的反饋和失速感。當發生垂直失速時，傾向於拉更多的後循環，這會延長失速時間並增加恢復時間。進行前循環調整以從失速狀態中恢復。這減少了誘導流，改善了結果的攻角，並減少了旋翼盤的圓錐形，從而增加了盤的總升力面積。飛行員會立即感覺到飛機方向的變化和增加的前進動量。
is moved forward. To avoid mushing, the pilot must use smooth and progressive application of the aft cyclic during high G-maneuvers such as dive recoveries and tight turns.
向前移動。為了避免模糊，飛行員必須在高 G 機動（如俯衝恢復和急轉彎）期間平滑且逐步地應用後方循環。
Conservation of Angular Momentum
角動量守恆
1-167. The law of conservation of angular momentum states the value of angular momentum of a rotating body will not change unless external torques are applied. In other words, a rotating body continues to rotate with the same rotational velocity until some external force is applied to change the speed of rotation. Angular momentum can be expressed as follows:
1-167. 角動量守恆定律指出，旋轉物體的角動量值不會改變，除非施加外部扭矩。換句話說，旋轉物體會以相同的旋轉速度繼續旋轉，直到施加某種外力來改變旋轉速度。角動量可以表示如下：
1-168. Changes in angular velocity, known as angular acceleration or deceleration, take place if the mass of a rotating body is moved closer to or further from the axis of rotation. The speed of the rotating mass increases or decreases in proportion to the square of the radius.
1-168. 角速度的變化，稱為角加速度或減速度，發生在旋轉物體的質量移動到離旋轉軸更近或更遠的地方時。旋轉質量的速度隨著半徑的平方成比例地增加或減少。
1-169. An excellent example for this principle is when watching a figure skater on ice skates. The skater begins a rotation on one foot, with the other leg and both arms extended. The rotation of the skater’s body is relatively slow. When a skater draws both arms and one leg inward, the moment of inertia (mass times radius squared) becomes much smaller and the body is rotating almost faster than the eye can follow. Because the angular momentum must, by law of nature, remain the same (no external force applied), the angular velocity must increase.
1-169. 這一原則的優秀範例是觀察一位花式滑冰選手在冰上滑行。滑冰者在一隻腳上開始旋轉，另一條腿和雙臂伸展。滑冰者的身體旋轉相對較慢。當滑冰者將雙臂和一條腿向內收回時，慣性矩（質量乘以半徑平方）變得小得多，身體的旋轉幾乎快到眼睛無法跟上。因為根據自然法則，角動量必須保持不變（沒有外力作用），所以角速度必須增加。
1-170. The mathematician, Coriolis, was concerned with forces generated by such radial movements of mass on a rotating disc or plane. These forces cause acceleration and deceleration. It may be stated as a mass moving radically—
1-170. 數學家科里奧利關注於在旋轉圓盤或平面上由質量的徑向運動產生的力量。這些力量會導致加速和減速。可以表述為一個質量以徑向運動—
Outward on a rotating disk exert a force on its surroundings opposite to rotation.
在旋轉的圓盤外部，對其周圍施加一個與旋轉方向相反的力。
Inward on a rotating disk exert a force on its surroundings in the direction of rotation.
在旋轉的圓盤內部，對其周圍施加一個沿著旋轉方向的力。
1-171. The major rotating elements in the system are the rotor blades. As the rotor begins to cone due to G- loading maneuvers, the diameter of the disc shrinks. Due to conservation of angular momentum, the blades continue to travel the same speed even though the blade tips have a shorter distance to travel due to reduced disc diameter. This action results in an increase in rotor RPMs. Most pilots arrest this increase with an increase in collective pitch.
1-171. 系統中的主要旋轉元件是轉子葉片。隨著轉子因 G 載荷操作而開始圓錐化，圓盤的直徑縮小。由於角動量守恆，葉片即使因圓盤直徑減小而行程縮短，仍然以相同的速度運行。這一行為導致轉子轉速的增加。大多數飛行員通過增加總揚力來抑制這一增長。
1-172. Conversely, as G-loading subsides and the rotor disc flattens out from the loss of G-load induced coning, the blade tips now have a longer distance to travel at the same tip speed. This action results in a reduction of rotor RPMs. However, if this droop in rotor continues to the point it attempts to decrease below normal operating RPM, the engine control system adds more fuel/power to maintain the specified engine RPM. If the pilot does not reduce collective pitch as the disc unloads, the combination of the engines compensating for the RPM slow down and the additional pitch added as G-loading increased may result in exceeding the torque limitations or power the engines can produce. This problem is exacerbated by effects of the TAF encountered during maneuvering flight.
1-172. 相反，隨著 G 載荷的減少和轉子盤因 G 載荷引起的圓錐形變而變平，葉片尖端在相同的尖端速度下現在需要移動更長的距離。這一行為導致轉子轉速的降低。然而，如果這種轉子下滑持續到試圖降低到正常操作轉速以下，發動機控制系統會增加更多的燃料/功率以維持指定的發動機轉速。如果飛行員在轉子盤卸載時不減少集體桨距，發動機為了補償轉速減慢而增加的功率與隨著 G 載荷增加而增加的額外桨距的組合，可能會導致超過發動機能夠產生的扭矩限制或功率。這一問題在機動飛行中受到遇到的 TAF 影響而加劇。
High Bank Angle Turns
高銀行角轉彎
1-173. As the angle of bank increases, the amount of lift opposite the vertical weight decreases (figure 1-71, page 1-53). If adequate excess engine power is available, increasing collective pitch enables continued flight while maintaining airspeed and altitude. If sufficient excess power is not available, the result is altitude loss unless airspeed is traded (aft cyclic) to maintain altitude or altitude is traded to maintain airspeed.
1-173. 隨著傾斜角度的增加，垂直重量對面的升力減少（圖 1-71，頁 1-53）。如果有足夠的多餘引擎功率，增加集體桨距可以在保持空速和高度的同時繼續飛行。如果沒有足夠的多餘功率，則會導致高度損失，除非通過降低空速（後循環）來維持高度，或是通過降低高度來維持空速。
Figure 1-71. Lift to weight
圖 1-71. 提升與重量
1-174. At some point (airspeed/angle of bank) sufficient excess power is not available and the aviator must apply aft cyclic to maintain altitude (table 1-3). The percentages shown are not a direct torque percentage, but percentage of torque increase required based on aircraft torque to maintain straight and level flight. If indicated cruise torque is 48 percent and a turn to 60 degrees is initiated, a torque increase of 48 percent (96 percent torque indicated) is required to maintain airspeed and altitude.
1-174. 在某個時刻（空速/傾斜角）可用的過剩功率不足，飛行員必須施加後循環以維持高度（表 1-3）。所示的百分比不是直接的扭矩百分比，而是基於飛機扭矩維持平直水平飛行所需的扭矩增加百分比。如果指示的巡航扭矩為 48％，並且開始轉向 60 度，則需要增加 48％的扭矩（指示 96％的扭矩）以維持空速和高度。
Table 1-3. Bank angle versus torque
表 1-3. 銀行角度與扭矩
Bank Angle-Degree | Increase in TR-Percent |
0 | --- |
15 | 3.6 |
30 | 15.4 |
45 | 41.4 |
60 | 100.0 |
TR=torque | |
1-175. Additionally, rotor system capability may limit the maneuver as opposed to insufficient excess power. In high energy maneuvering, the rotor is normally a limiting factor. It is not unusual for a reduction in collective to be required to achieve maximum performance when maneuvering at increased G-loads, altitudes, or high weights.
1-175。此外，旋翼系統的能力可能會限制機動，而不是因為過剩功率不足。在高能量機動中，旋翼通常是限制因素。在增加 G 負荷、高高度或高重量的機動中，通常需要降低集體桨距以達到最佳性能。
1-176. Aviators must be familiar with this characteristic, anticipate cyclic input results, and apply appropriate control inputs to conduct combat maneuvers successfully. Aviators unfamiliar with this characteristic may be surprised at the rapid build of sink rates when turning the aircraft to bank angles approaching 60 degrees. When flying heavy aircraft in a high hot environment, sufficient time and altitude may not be available to arrest the resultant descent.
1-176. 飛行員必須熟悉這一特性，預測循環輸入的結果，並施加適當的控制輸入以成功執行戰鬥機動。對這一特性不熟悉的飛行員在將飛機轉向接近 60 度的傾斜角時，可能會對快速增加的下沉率感到驚訝。在高溫環境中駕駛重型飛機時，可能沒有足夠的時間和高度來阻止隨之而來的下降。
Maneuvering Flight and Total Aerodynamic Force
操控飛行與總空氣動力學力
1-177. The cyclic inputs and associated rotor disc pitch changes required to accomplish successful combat maneuvers have a substantial effect on TAF. Large aft cyclic inputs increase inflow through the rotor system. Since lift is perpendicular to resultant relative wind, the TAF of each rotor blade may move to a point aligned with or forward of the axis of rotation (much like the driving and driven region of a blade during autorotational flight). While the engine control system reduces fuel flow to reduced load, the rotor system may still climb to transient ranges or attempt to overspeed.
1-177. 為了成功執行戰鬥機動，所需的循環輸入和相關的轉子盤傾斜變化對 TAF 有著顯著影響。大型後方循環輸入增加了通過轉子系統的進氣量。由於升力垂直於結果相對風，每個轉子葉片的 TAF 可能會移動到與旋轉軸對齊或位於其前方的點（就像在自轉飛行中葉片的驅動區和被驅動區）。當引擎控制系統減少燃料流量以降低負載時，轉子系統仍可能爬升到瞬態範圍或嘗試超速。
1-178. Conversely, when the cyclic is rapidly repositioned to a more forward position, inflow through the rotor is rapidly reduced resulting in the blade TAF moving aft of the axis of rotation and a slowing of rotor RPM
1-178. 相反，當循環快速重新定位到更前的位置時，通過轉子進氣迅速減少，導致葉片的 TAF 移動到旋轉軸的後方，並使轉子 RPM 減慢。
(figure 1-72). The engine control systems sense this and increase fuel flow to the engines to maintain rotor RPM causing torque to increase. As a general rule, when traveling at airspeeds above bucket speed, aft cyclic results in a reduction in torque and an increase in rotor RPMs. Recovery from an aft cyclic input (pushover or high G- turn recovery) results in torque increase as the engines compensate for the rotor system slow down. In aggressive maneuvers, this may result in an overtorque or overspeed if appropriate collective input is not made to keep torque and rotor consistent.
（圖 1-72）。引擎控制系統感知到這一點，並增加引擎的燃料流量以維持轉子轉速，導致扭矩增加。一般來說，當以高於桶速的空速行駛時，後循環會導致扭矩減少和轉子轉速增加。從後循環輸入（推壓或高 G 轉彎恢復）中恢復時，扭矩會增加，因為引擎補償轉子系統的減速。在激烈的機動中，如果未適當調整集體輸入以保持扭矩和轉子一致，這可能會導致過扭矩或過轉速。
Figure 1-72. Aft cyclic results
圖 1-72. 後循環結果
1-179. This phenomenon is exacerbated by high gross weight and also affected by ambient temperature and density altitude. Typically, cold dry air results in more rapid rotor RPM increase during aft cyclic input and a corresponding higher torque increase with a forward cyclic input. Hot temperatures and higher density altitudes result in more collective input required to arrest a climbing rotor.
1-179. 這一現象因高總重量而加劇，並受到環境溫度和密度高度的影響。通常，冷乾空氣會導致在後向循環輸入時轉子轉速（RPM）更快速地增加，而在前向循環輸入時則會相應地增加更高的扭矩。高溫和較高的密度高度會導致需要更多的集體輸入來停止上升的轉子。
Angular Momentum and Total Aerodynamic Force Combined Effects
角動量與總空氣動力作用的綜合效應
1-180. Angular momentum and TAF combine during cyclic pitch changes. During aft cyclic or G-loading, the rotor increases and torque goes down. During G-load recovery, torque increases as the engine control systems work to maintain a rotor RPM attempting to decrease. Aviators must be able to apply appropriate and timely collective inputs to maintain consistent torque and keep rotor RPM within limits.
1-180. 角動量和 TAF 在循環變距變化期間結合。在後循環或 G 載荷期間，轉子增加而扭矩下降。在 G 載荷恢復期間，隨著引擎控制系統努力維持試圖降低的轉子 RPM，扭矩增加。飛行員必須能夠適時地施加適當的總控輸入，以維持穩定的扭矩並將轉子 RPM 保持在限制範圍內。
Dig-In
深入探索
1-181. Dig-in is applying aft cyclic to such a point that causes the main rotor disk thrust vector to almost parallel the flight path of the helicopter. While making large aft cyclic movements, the pilot must be aware of the helicopter’s tendency to rapidly and unpredictably build G-forces. As the cyclic is moved aft, the rotor disk responds by tilting aft, which tilts the thrust vector aft and ultimately causes the aircraft to pitch nose-up. This rapid pitch-up also increases the length of the aircraft thrust vector, which increases the pitch-up rate. The rapid onset of the pitch-up motion due to this tilting and then lengthening of the thrust vector, is considered destabilizing and countered by the helicopter’s horizontal tail or stabilizer which tries to drive the nose back down. For large pitch-up rates, the tendency of the main rotor to continue pitching-up overpowers the horizontal tail/stabilizer and the aircraft digs-in and slow down rapidly. Dig-in could be accompanied by airframe vibration and sometimes control feedback. Vibration and control feedback is normally canceled out by modern aircraft systems.
1-181. 鑽入是將後循環操縱杆應用到一個點，使主旋翼盤的推力向量幾乎與直升機的飛行路徑平行。在進行大幅度後循環操縱時，飛行員必須意識到直升機迅速且不可預測地產生 G 力的傾向。當循環操縱杆向後移動時，旋翼盤會向後傾斜，這會使推力向量向後傾斜，最終導致飛機的機頭向上仰起。這種快速的仰頭也增加了飛機推力向量的長度，從而提高了仰頭速率。由於這種傾斜和隨後推力向量的延長而導致的仰頭運動的快速出現，被認為是破壞穩定的，並受到直升機的水平尾翼或穩定器的抵消，後者試圖將機頭壓回向下。對於大仰頭速率，主旋翼繼續仰頭的傾向壓倒了水平尾翼/穩定器，飛機會鑽入並迅速減速。鑽入可能伴隨著機身振動，有時還會有控制反饋。現代飛機系統通常會消除振動和控制反饋。
1-182. Aft cyclic movements give predictable increases in G-load up to the dig-in point; however, the dig-in occurs at different G-levels for each model of helicopter. The point at which dig-in occurs depends on a number of factors, but most important is the size of the horizontal tail/stabilizer and amount of rotor offset. For most helicopters, this point is between 1.5 and 2.0 Gs. Pilots should be prepared for dig-in during aggressive aft cyclic inputs, especially during break turns.
1-182. 後循環動作會在進入挖掘點之前預測性地增加 G 負載；然而，挖掘發生的 G 水平對於每種直升機模型而言是不同的。挖掘發生的點取決於多個因素，但最重要的是水平尾翼/穩定器的大小和旋翼偏移量。對於大多數直升機而言，這一點介於 1.5 到 2.0 G 之間。飛行員應該在進行激烈的後循環輸入時，特別是在轉彎時，做好挖掘的準備。
GUIDELINES
指導方針
1-183. Below are good practices to follow during maneuvering flight:
1-183. 以下是在機動飛行期間應遵循的良好實踐：
Never move the cyclic faster than trim, torque, and rotor can be maintained. When entering a maneuver and the trim, rotor, or torque reacts quicker than anticipated, pilot limitations have been exceeded. If continued, the aircraft limitation is exceeded. The maneuver is performed with less intensity until all aspects of the machine can be controlled.
永遠不要讓循環的速度超過修整、扭矩和旋翼所能維持的速度。當進入一個機動時，如果修整、旋翼或扭矩的反應比預期更快，則超出了飛行員的限制。如果繼續這樣做，則超出了飛機的限制。該機動應以較低的強度進行，直到所有機器的各個方面都能被控制。
Changes are anticipated in aircraft performance due to loading or environmental condition. The normal collective increase to check rotor speed at sea level standard may not be sufficient at 4,000 feet pressure altitude (PA) and 95 degrees F (4K95).
由於載荷或環境條件，預期飛機性能會發生變化。在海平面標準下檢查轉子速度的正常集體增加，在 4,000 英尺壓力高度（PA）和 95 華氏度（4K95）時可能不足。
The following characteristics are anticipated during aggressive maneuvering flight and adjust or lead with collective as necessary to maintain trim and torque:
在激烈機動飛行期間預期會出現以下特徵，並根據需要調整或引導集體以維持平衡和扭矩：
Left turns, torque increases.
左轉時，扭矩增加。
Right turns, torque decreases.
右轉時，扭矩減少。
Application of aft cyclic, torque decreases and rotor climbs.
應用尾旋轉，扭矩減少，轉子上升。
Application of forward cyclic (especially when immediately following aft cyclic application), torque increases and rotor speed decreases.
前向循環的應用（特別是在隨後立即施加後向循環時），扭矩增加而轉子速度減少。
Always leave a way out.
永遠留一條退路。
Know where the winds are.
知道風向。
Most engine malfunctions occur during power changes.
大多數引擎故障發生在功率變化期間。
If combat maneuvers have not been performed in a while, start slowly to develop proficiency.
如果已經有一段時間沒有進行戰鬥演習，請慢慢開始以提高熟練度。
Crew coordination is critical. Everyone needs to be fully aware of what is going on and each crewmember has a specific duty.
船員協調至關重要。每個人都需要充分了解正在發生的事情，每位船員都有特定的職責。
In steep turns the nose drops. In most cases, energy (airspeed) must be traded to maintain altitude as the required excess engine power may not be available (to maintain airspeed in a 2G/60 degree turn rotor thrust/engine power has to increase by 100 percent). Failure to anticipate this at low altitude endangers the crew and passengers. The rate of pitch change is proportional to gross weight and density altitude.
在急轉彎時，機頭會下沉。在大多數情況下，必須以能量（空速）來交換以維持高度，因為所需的多餘引擎功率可能無法提供（在 2G/60 度轉彎中，旋翼推力/引擎功率必須增加 100%）。未能在低高度預見這一點會危及機組人員和乘客的安全。俯仰變化率與總重量和密度高度成正比。
Many maneuvering flight over-torques occur as the aircraft unloads Gs. This is due to insufficient collective reduction following the increase to maintain consistent torque and rotor as G-loading increased (dive recovery or recovery from high G-turn to the right).
許多操控飛行過度扭矩的情況發生在飛機減少 G 力時。這是因為在 G 負荷增加（俯衝恢復或從高 G 向右轉的恢復）後，未能充分減少集體桨距以維持一致的扭矩和旋翼。
1-184. A helicopter’s performance is dependent upon the power output of the engine and lift production of the rotors. Any factor affecting engine and rotor efficiency affects performance. The three major factors affecting performance are density altitude, weight, and wind.
1-184. 直升機的性能取決於引擎的功率輸出和旋翼的升力產生。任何影響引擎和旋翼效率的因素都會影響性能。影響性能的三個主要因素是密度高度、重量和風。
DENSITY ALTITUDE
密度高度
1-185. As air density increases, engine power output, rotor efficiency, and aerodynamic lift also increase. Density altitude is the altitude above mean sea level (MSL) at which a given atmospheric density occurs in the standard atmosphere. It can also be interpreted as PA corrected for nonstandard temperature differences.
1-185. 隨著空氣密度的增加，發動機功率輸出、轉子效率和空氣動力學升力也隨之增加。密度高度是指在標準大氣中，特定大氣密度出現的平均海平面（MSL）之上高度。它也可以解釋為針對非標準溫度差進行修正的 PA。
1-186. PA is displayed as the height above a standard datum plane, which in this case, is a theoretical plane where air pressure is equal to 29.92 inches mercury (Hg). PA is the indicated height value when the altimeter setting is adjusted to 29.92 inches Hg. PA, as opposed to true altitude, is an important value for calculating performance as it more accurately represents the air content at a particular level. The difference between true altitude and PA must be clearly understood. True altitude means the vertical height above MSL and is displayed on the altimeter when the altimeter is correctly adjusted to the local setting.
1-186. PA 顯示為高於標準基準平面的高度，在這種情況下，這是一個理論平面，空氣壓力等於 29.92 英寸汞柱 (Hg)。當高度計的設定調整為 29.92 英寸 Hg 時，PA 是指示的高度值。PA 與真實高度相對，是計算性能的重要值，因為它更準確地代表特定高度的空氣含量。必須清楚理解真實高度與 PA 之間的差異。真實高度是指高於海平面的垂直高度，當高度計正確調整為當地設定時，會在高度計上顯示。
1-187. For example, if the local altimeter setting is 30.12 inches Hg and adjusted to this value, it indicates exact height above sea level. However, this does not reflect conditions found at this height under standard conditions. Since the altimeter setting is more than 29.92 inches Hg, the air in this example has a higher pressure and is more compressed, indicative of air found at a lower altitude. Therefore, the PA is lower than the actual height above MSL. To calculate PA without use of an altimeter, remember pressure decreases approximately 1 inch of mercury for every 1,000-foot increase in altitude. For example, if the current local altimeter setting at a 4,000 foot elevation is 30.42, the PA would be 3,500 feet (30.42 – 29.92 = .50 inches Hg/.50 x 1,000 feet = 500
1-187. 例如，如果當地的高度計設定為 30.12 英寸汞柱並調整至此值，則表示海平面以上的確切高度。然而，這並不反映在標準條件下此高度的實際情況。由於高度計設定超過 29.92 英寸汞柱，這個例子中的空氣壓力較高且更為壓縮，顯示出在較低高度的空氣。因此，絕對氣壓（PA）低於海平面以上的實際高度。要在不使用高度計的情況下計算 PA，請記住，壓力每增加 1,000 英尺高度約下降 1 英寸汞柱。例如，如果當前在 4,000 英尺高度的當地高度計設定為 30.42，則 PA 將為 3,500 英尺（30.42 – 29.92 = .50 英寸汞柱/.50 x 1,000 英尺 = 500）。
feet; subtracting 500 feet from 4,000 equals 3,500 feet.). Four factors affecting density altitude most are atmospheric pressure, altitude, temperature, and moisture content of the air.
英尺；從 4,000 英尺中減去 500 英尺等於 3,500 英尺。影響密度高度的四個主要因素是大氣壓力、高度、溫度和空氣的濕度含量。
Atmospheric Pressure
大氣壓力
1-188. Due to changing weather conditions, atmospheric pressure at a given location changes from day to day. If the pressure is lower, the air is less dense. This means a higher density altitude and less helicopter performance.
1-188. 由於天氣條件變化，特定位置的氣壓每天都會變化。如果氣壓較低，空氣的密度就較小。這意味著較高的密度高度和較差的直升機性能。
Altitude
高度
1-189. As altitude increases, air becomes thinner. This is because the atmospheric pressure acting on a given volume of air is less, allowing air molecules to move further apart. Dense air contains air molecules spaced closely together, while thin air contains air molecules spaced further apart. As altitude increases, density altitude increases.
1-189. 隨著高度的增加，空氣變得稀薄。這是因為作用於特定空氣體積的氣壓較低，使得空氣分子能夠更遠地分開。密集的空氣包含緊密排列的空氣分子，而稀薄的空氣則包含較遠排列的空氣分子。隨著高度的增加，密度高度也隨之增加。
Temperature
溫度
1-190. As warm air expands the air molecules move further apart, creating less dense air. Since cool air contracts, air molecules move closer together creating denser air. High temperatures cause even low elevations to have high density altitudes.
1-190. 當暖空氣膨脹時，空氣分子之間的距離變得更遠，形成較低密度的空氣。由於冷空氣收縮，空氣分子之間的距離變得更近，形成較高密度的空氣。高溫使得即使在低海拔地區也會有高密度的高度。
Moisture (Humidity)
濕度 (濕氣)
1-191. The water content of air also changes air density as water vapor weighs less than dry air. Therefore, as the water content of the air increases, air becomes less dense, increasing density altitude and decreasing performance.
1-191. 空氣的水分含量也會改變空氣密度，因為水蒸氣的重量低於乾燥空氣。因此，隨著空氣水分含量的增加，空氣變得不那麼密集，導致密度高度增加和性能下降。
1-192. Humidity, also called relative humidity, refers to the amount of water vapor contained in the atmosphere and is expressed as a percentage of the maximum amount of water vapor air can hold. This amount varies with temperature; warm air can hold more water vapor, while colder air holds less. Perfectly dry air that contains no water vapor has a relative humidity of 0 percent, while saturated air that cannot hold any more water vapor has a relative humidity of 100 percent.
1-192. 濕度，也稱為相對濕度，指的是大氣中所含水蒸氣的量，並以空氣能夠容納的最大水蒸氣量的百分比表示。這個數量隨著溫度而變化；暖空氣能夠容納更多的水蒸氣，而冷空氣則能容納較少的水蒸氣。完全乾燥的空氣不含水蒸氣，其相對濕度為 0 百分比，而飽和空氣無法再容納更多水蒸氣，其相對濕度為 100 百分比。
1-193. Humidity alone is usually not considered an important factor in calculating density altitude and helicopter performance however, it does contribute. There are no rules-of-thumb or charts used to compute the effects of humidity on density altitude. Aviators should expect a decrease in hovering and takeoff performance in high humidity conditions.
1-193. 濕度通常不被視為計算密度高度和直升機性能的重要因素，然而，它確實有影響。沒有經驗法則或圖表用於計算濕度對密度高度的影響。飛行員應該預期在高濕度條件下懸停和起飛性能會下降。
HIGH AND LOW DENSITY ALTITUDE CONDITIONS
高低密度高度條件
1-194. A thorough understanding of the terms high density altitude and low density altitude are required. In general, high density altitude refers to thin air, while low density altitude refers to dense air. Those conditions resulting in a high density altitude (thin air) are high elevations, low atmospheric pressure, high temperatures, high humidity, or some combination thereof. Lower elevations, high atmospheric pressure, low temperatures, and low humidity are more indicative of low density altitude (dense air). However, high density altitudes may be present at lower elevations on hot days, so it is important to calculate density altitude and determine performance before a flight.
1-194. 需要對高密度高度和低密度高度的術語有透徹的理解。一般來說，高密度高度指的是稀薄的空氣，而低密度高度則指的是濃密的空氣。導致高密度高度（稀薄空氣）的條件包括高海拔、低大氣壓、高溫、高濕度或其某種組合。較低的海拔、高大氣壓、低溫和低濕度則更能表明低密度高度（濃密空氣）。然而，在炎熱的日子裡，低海拔地區也可能出現高密度高度，因此在飛行前計算密度高度並確定性能是很重要的。
1-195. One of the ways density altitude can be determined (CPU-26A/P is another) is through use of charts designed for that purpose (figure 1-73, page 1-57). The graph is used to find density altitude either on the ground or aloft. Set altimeter at 29.92 inches to indicate PA. Read outside air temperature (OAT). Enter the graph at that PA and move horizontally to the temperature. Read density altitude from the sloping lines.
1-195. 確定密度高度的方法之一（CPU-26A/P 是另一種）是通過使用為此目的設計的圖表（圖 1-73，頁 1-57）。該圖表用於查找地面或高空的密度高度。將高度計設置為 29.92 英寸以顯示 PA。讀取外部空氣溫度（OAT）。在該 PA 進入圖表，並水平移動到溫度。從斜線上讀取密度高度。
Example 1. Find density altitude in flight. PA is 9,500 feet and temperature is 18 degrees F. Find 9,500 feet on the left of the graph and move across to 18 degrees F. density altitude is 9,000 feet (marked 1 on the graph).
範例 1. 在飛行中找出密度高度。海平面高度為 9,500 英尺，溫度為 18 華氏度。在圖的左側找到 9,500 英尺，然後移動到 18 華氏度。密度高度為 9,000 英尺（在圖上標記為 1）。
Example 2. Find density altitude for takeoff. PA is 4,950 feet and temperature is 97 degrees F. Enter the graph at 4,950 feet and move across to 97 degrees F. Density altitude is 8,200 feet (marked 2 on graph).
範例 2. 找出起飛的密度高度。氣壓為 4,950 英尺，溫度為 97 華氏度。從 4,950 英尺進入圖表，然後移動到 97 華氏度。密度高度為 8,200 英尺（在圖表上標記為 2）。
Note. In warm air, density altitude is considerably higher than PA.
注意。在暖空氣中，密度高度顯著高於氣壓高度。
1-196. Most performance charts do not require computation of density altitude; instead, the computation is built into the performance chart. All that remains is to enter the correct PA and temperature.
1-196. 大多數性能圖表不需要計算密度高度；相反，計算已內建於性能圖表中。剩下的只是輸入正確的氣壓高度和溫度。
Figure 1-73. Density altitude computation
圖 1-73. 密度高度計算
WEIGHT
重量
1-197. Weight is the force opposing lift. As weight increases, power required to produce lift needed to compensate for the added weight must also increase. Most performance charts include weight as one of the variables. By reducing weight, the helicopter is able to safely takeoff or land at a location otherwise impossible. However, if in doubt, takeoff is delayed until more favorable density altitude conditions exists. If airborne, land at a location that has more favorable conditions or one where a landing can be made that does not require a hover.
1-197. 重量是對抗升力的力量。隨著重量的增加，產生升力所需的功率也必須增加，以補償增加的重量。大多數性能圖表將重量作為變數之一。通過減少重量，直升機能夠安全地在原本不可能的地方起飛或降落。然而，如果有疑慮，起飛將延遲，直到出現更有利的密度高度條件。如果已在空中，則應降落在條件更有利的地方，或在不需要懸停的地方降落。
1-198. At higher gross weights the increased power required to hover produces more torque, which means more antitorque thrust is required. In some helicopters, during high altitude operations, the maximum antitorque produced by the tail rotor during a hover may not be sufficient to overcome torque even if the gross weight is within limits.
1-198. 在較高的總重量下，懸停所需的增加功率會產生更多的扭矩，這意味著需要更多的反扭矩推力。在某些直升機中，在高海拔操作期間，即使總重量在限制範圍內，尾旋翼在懸停時產生的最大反扭矩也可能不足以克服扭矩。
WINDS
1-199. Wind direction and velocity also affect hovering, takeoff, and climb performance. Translational lift occurs any time there is relative airflow over the rotor disc. This occurs whether the relative airflow is caused
1-199. 風向和風速也會影響懸停、起飛和爬升性能。當旋翼盤上有相對氣流時，就會產生平移升力。這種情況無論是由相對氣流引起的。
by helicopter movement or wind. As wind speed increases, translational lift increases, resulting in less power required to hover.
透過直升機的運動或風。隨著風速的增加，平移升力增加，導致懸停所需的功率減少。
1-200. Wind direction is also an important consideration. Headwinds are desirable as they contribute to the most increase in performance. Strong crosswinds and tailwinds may require use of more tail rotor thrust to maintain directional control. This increased tail rotor thrust absorbs power from the engine, which means less power is available to the main rotor for production of lift. Some helicopters even have a critical wind azimuth or maximum safe relative wind chart. Operating the helicopter beyond these limits could cause loss of tail rotor effectiveness.
1-200. 風向也是一個重要的考量因素。逆風是理想的，因為它們對性能的提升貢獻最大。強烈的側風和順風可能需要使用更多的尾旋翼推力來維持方向控制。這種增加的尾旋翼推力會消耗引擎的功率，這意味著可用於主旋翼產生升力的功率會減少。一些直升機甚至有一個關鍵風方位或最大安全相對風圖表。超出這些限制操作直升機可能會導致尾旋翼效能下降。
1-201. Takeoff and climb performance is greatly affected by wind. When taking off into a headwind ETL is achieved earlier, resulting in more lift and a steeper climb angle. When taking off with a tailwind more distance is required to accelerate through translation lift.
1-201. 起飛和爬升性能受到風的重大影響。當迎著逆風起飛時，ETL 會更早達成，導致產生更多的升力和更陡的爬升角度。當順著順風起飛時，則需要更長的距離來加速通過轉換升力。
PERFORMANCE CHARTS
性能圖表
1-202. In developing performance charts, aircraft manufacturers make certain assumptions about the condition of the helicopter and ability of the pilot. It is assumed the helicopter is in good operating condition and the engine is developing its rated power. The pilot is assumed to be following normal operating procedures and to have average flying abilities. Average means a pilot capable of doing each of the required tasks correctly and at appropriate times.
1-202。在開發性能圖表時，飛機製造商對直升機的狀況和飛行員的能力做出某些假設。假設直升機處於良好的操作狀態，且引擎發揮其額定功率。假設飛行員遵循正常的操作程序，並具備平均的飛行能力。平均指的是能夠正確且在適當時間內完成每項所需任務的飛行員。
1-203. Using these assumptions, the manufacturer develops performance data for the helicopter based on actual flight tests. However, they do not test the helicopter under each and every condition shown on a performance chart. Instead, they evaluate specific data and mathematically derive the remaining data.
1-203. 根據這些假設，製造商根據實際飛行測試開發直升機的性能數據。然而，他們並不在性能圖表上顯示的每一種條件下測試直升機。相反，他們評估特定數據並數學推導出其餘數據。
HOVERING PERFORMANCE
懸停性能
1-204. Helicopter performance revolves around whether or not hover is possible. More power is required during hover than in any other flight regime. Obstructions aside, if hover can be maintained, takeoff can be made, especially with the additional benefit of translational lift. Charts are provided for IGE and OGE under various conditions of gross weight, altitude, temperature, and power. The IGE hover ceiling is higher than OGE hover ceiling due to the added lift benefit produced by ground effect.
1-204. 直升機的性能圍繞著是否能夠懸停。在懸停時所需的功率比其他任何飛行狀態都要高。撇開障礙物不談，如果能夠維持懸停，就可以起飛，特別是還有平移升力的額外好處。提供了在不同的總重量、高度、溫度和功率條件下的 IGE 和 OGE 圖表。由於地面效應產生的額外升力，IGE 懸停天花板高於 OGE 懸停天花板。
1-205. As density altitude increases more power is required to hover. At some point, the power required is equal to the power available. This establishes the hovering ceiling under existing conditions. Any adjustment to gross weight by varying fuel, payload, or both, affects the hovering ceiling. The heavier the gross weight, the lower the hovering ceiling. As gross weight is decreased, the hover ceiling increases.
1-205. 隨著密度高度的增加，懸停所需的功率也會增加。在某個時刻，所需的功率等於可用的功率。這確定了在現有條件下的懸停天花板。通過改變燃料、有效載荷或兩者來調整總重量，會影響懸停天花板。總重量越重，懸停天花板越低。隨著總重量的減少，懸停天花板會增加。
1-206. Being able to hover at the takeoff location with a certain gross weight does not ensure the same performance at the landing point. If the destination point is at a higher density altitude because of higher elevation, temperature, and/or relative humidity, more power is required to hover. You should be able to predict whether hovering power will be available at the destination by knowing the temperature and wind conditions. Using performance charts in the helicopter flight manual, and making certain power checks during hover and in flight prior to commencing the approach and landing.
1-206. 能夠在起飛位置以某一總重量懸停並不保證在著陸點有相同的性能。如果目的地因為較高的海拔、高溫和/或相對濕度而位於較高的密度高度，則需要更多的功率來懸停。您應該能夠通過了解溫度和風況來預測目的地是否有懸停功率可用。使用直升機飛行手冊中的性能圖表，並在接近和著陸之前進行某些功率檢查。
CLIMB PERFORMANCE
攀登性能
1-207. Most factors affecting hover and takeoff performance also affect climb performance. In addition, turbulent air, pilot techniques, and overall condition of the helicopter can cause climb performance to vary.
1-207. 大多數影響懸停和起飛性能的因素也會影響爬升性能。此外，湍流空氣、飛行員技術和直升機的整體狀況也會導致爬升性能的變化。
1-208. A helicopter flown at the best rate-of-climb speed obtains the greatest gain in altitude over a given period of time. This speed is normally used during the climb after all obstacles have been cleared and is usually maintained until reaching cruise altitude. Rate of climb must not be confused with angle of climb. Angle of climb is a function of altitude gained over a given distance. The best rate-of-climb speed results in the highest climb rate, but not the steepest climb angle and may not be sufficient to clear obstructions. The best angle-of- climb speed depends upon power available. If there is a surplus of power available the helicopter can climb vertically; therefore, the best angle-of-climb speed is zero.
1-208. 直升機在最佳爬升速率下飛行，能在給定的時間內獲得最大的高度增益。這個速度通常在清除所有障礙物後的爬升階段使用，並通常保持直到達到巡航高度。爬升速率不應與爬升角度混淆。爬升角度是指在給定距離內獲得的高度。最佳爬升速率會導致最高的爬升速率，但不一定是最陡的爬升角度，並且可能不足以清除障礙物。最佳爬升角度速度取決於可用的功率。如果有多餘的功率可用，直升機可以垂直爬升；因此，最佳爬升角度速度為零。
1-209. Wind direction and speed have an effect on climb performance, but it is often misunderstood. Airspeed is the speed at which the helicopter is moving through the atmosphere and is unaffected by wind. Atmospheric wind affects only the ground speed and ground track.
1-209. 風向和風速對爬升性能有影響，但常常被誤解。空速是直升機在大氣中移動的速度，並不受風的影響。大氣風僅影響地面速度和地面航跡。
1-210. Generally speaking, aerodynamic emergencies can be avoided by removing at least one of the factors necessary for emergency to occur. Pre-mission planning will identify aerodynamic profiles to avoid. Operating within appropriate common standards and task specific standards significantly minimizes the risk.
1-210. 一般來說，通過去除至少一個必要的因素，可以避免氣動緊急情況的發生。任務前的規劃將識別需要避免的氣動輪廓。在適當的通用標準和任務特定標準內操作，能顯著降低風險。
SETTLING WITH POWER
以權力解決問題
1-211. Settling with power (figures 1-74 through 1-76) is a condition of powered flight in which the helicopter settles in its own downwash. This condition may also be referred to as vortex ring state. Under certain conditions the helicopter may descend at a high rate which exceeds the normal downward induced flow rate of the inner blade sections (inner section of the rotor disk). Therefore, the airflow of the inner blade sections is upward relative to the disk. This produces a secondary vortex ring in addition to the normal tip vortex system. The secondary vortex ring is generated about the point on the blade where airflow changes from up to down. The result is an unsteady turbulent flow over a large area of the disk which causes loss of rotor efficiency although engine power is still supplied to the rotor system.
1-211. 以動力降落（圖 1-74 至 1-76）是直升機在其自身下洗氣流中降落的動力飛行狀態。這種狀態也可稱為渦環狀態。在某些條件下，直升機可能以超過內葉片部分（轉子盤的內部區域）正常向下誘導流速的高速度下降。因此，內葉片部分的氣流相對於轉子盤是向上的。這會產生一個次級渦環，除了正常的尖端渦流系統之外。次級渦環是在葉片上氣流從向上變為向下的點周圍產生的。其結果是在轉子盤的大面積上產生不穩定的湍流，雖然仍然有引擎動力供應給轉子系統，但這會導致轉子效率的損失。
1-212. Figure 1-74 shows normal induced flow velocities along the blade span during hovering flight. Downward velocity is highest at the blade tip where blade speed is highest. As blade speed decreases nearer the center of the disk, downward velocity is less.
1-212. 圖 1-74 顯示了在懸停飛行期間沿著葉片跨度的正常誘導流速。向下的速度在葉片尖端最高，因為葉片速度在此處最高。隨著葉片速度在圓盤中心附近減少，向下的速度也較低。
Figure 1-74. Induced flow velocity during hovering flight
圖 1-74. 懸停飛行期間的誘導流速
1-213. Figure 1-75 shows the induced airflow velocity pattern along the blade span during a descent conducive to settling with power. The descent is so rapid, induced flow at the inner portion of the blades is upward rather than downward. The upflow caused by the descent has overcome the downflow produced by blade rotation and pitch angle.
1-213. 圖 1-75 顯示了在有利於帶動降落的下降過程中，葉片跨度上的誘導氣流速度模式。下降速度非常快，葉片內部的誘導氣流是向上而非向下。由於下降造成的上升氣流已經克服了由葉片旋轉和桨距角產生的下行氣流。
Figure 1-75. Induced flow velocity before vortex ring state
圖 1-75. 渦環狀態前的誘導流速
1-214. If this rate of descent exists with insufficient power to slow or stop the descent, it enters the vortex ring state (figure 1-76, page 1-60). During this vortex ring state, roughness and loss of control occur due to turbulent rotational flow on the blades and unsteady shifting of the flow along the blade span.
1-214. 如果這種下降速率存在而無法提供足夠的功率來減慢或停止下降，則會進入漩渦環狀狀態（圖 1-76，頁 1-60）。在這種漩渦環狀狀態下，由於葉片上的湍流旋轉流動和沿葉片跨度的不穩定流動轉移，會發生粗糙感和失去控制。
Figure 1-76. Vortex ring state
圖 1-76. 渦環狀態
1-215. The following conditions must exist simultaneously for settling with power to occur:
1-215. 必須同時存在以下條件才能進行帶電結算：
A vertical or near-vertical descent of at least 300 feet per minute (FPM). Actual critical rate depends on gross weight, rotor RPM, density altitude, and other pertinent factors.
垂直或接近垂直的下降速率至少為每分鐘 300 英尺 (FPM)。實際的臨界速率取決於總重量、旋翼轉速、密度高度及其他相關因素。
Slow forward airspeed (less than ETL).
慢速前進空速（低於有效轉換高度）。
Rotor system must be using 20 to 100 percent of the available engine power with insufficient power remaining to arrest the descent. Low rotor RPM could aggravate this.
轉子系統必須使用可用引擎功率的 20%至 100%，而剩餘的功率不足以停止下降。低轉子轉速可能會加劇這一情況。
1-216. The following flight conditions are conducive to settling with power:
1-216. 以下飛行條件有利於帶動穩定：
Steep approach at a high rate of descent.
陡峭的進場以高下降率。
Downwind approach.
順風進場。
Formation flight approach (where settling with power could be caused by turbulence of preceding aircraft).
編隊飛行接近（前方飛機的湍流可能導致動力下降）。
Hovering above the maximum hover ceiling.
懸停在最大懸停高度之上。
Not maintaining constant altitude control during an OGE hover.
在超出地面效應懸停時未保持恆定高度控制。
During masking/unmasking.
在遮蔽/解除遮蔽期間。
1-217. Recovery from settling with power may be affected by one, or a combination, of the following ways:
1-217. 從沉降中恢復的能力可能受到以下一種或多種方式的影響：
During the initial stage (when a large amount of excess power is available), a large application of collective pitch may arrest rapid descent. If done carelessly or too late, collective increase can aggravate the situation resulting in more turbulence and an increased rate of descent.
在初始階段（當有大量多餘的功率可用時），大幅度的集體變距可能會阻止快速下降。如果操作不當或太晚，集體增加可能會使情況惡化，導致更多的湍流和下降速率的增加。
In single-rotor helicopters, aviators can accomplish recovery by applying cyclic to gain airspeed and arrest upward induced flow of air and/or by lowering the collective (altitude permitting). Normally, gaining airspeed is the preferred method as less altitude is lost. In most helicopters, lateral cyclic thrust combined with an increase in power and lateral antitorque thrust produces the quickest exit from the hazard.
在單旋翼直升機中，飛行員可以通過施加循環控制來獲得空速並阻止向上的氣流，和/或通過降低集體控制（在高度允許的情況下）來完成恢復。通常，獲得空速是首選方法，因為損失的高度較少。在大多數直升機中，側向循環推力結合增加的功率和側向反扭矩推力能最快地脫離危險。
In tandem-rotor helicopters, fore and aft cyclic inputs aggravate the situation. By lowering thrust (altitude permitting) and applying lateral cyclic input or pedal input to arrest this upward induced flow of air, the aviator can accomplish recovery.
在雙旋翼直升機中，前後的循環輸入會加劇情況。通過降低推力（在高度允許的情況下）並施加側向循環輸入或踏板輸入來阻止這種向上的氣流，飛行員可以實現恢復。
1-218. Several conclusions can be drawn from figure 1-77, page 1-61—
1-218. 從圖 1-77（第 1-61 頁）可以得出幾個結論—
The vortex ring state can be completely avoided by descending on flight paths shallower than about 30 degrees (at any speed).
渦環狀態可以通過在約 30 度（以任何速度）以下的飛行路徑上下降來完全避免。
For steeper approaches, the vortex ring state can be avoided by using rates of descent versus horizontal velocity either faster or slower than those passing through the area of severe turbulence and thrust variation.
對於較陡的進場，通過使用下降速率與水平速度的比率，無論是快於還是慢於經過嚴重湍流和推力變化區域的速率，都可以避免渦環狀態。
At very shallow angles of descent, the vortex ring wake is dispersed behind the helicopter. Forward airspeed coupled with induced-flow velocity prevents the upflow from materializing on the rotor system.
在非常淺的下降角度下，渦環尾流在直升機後方擴散。前進的空速與誘導流速結合，防止了在旋翼系統上形成上升流。
At steep angles, the vortex ring wake is below the helicopter at slow rates of descent and above the helicopter at high rates of descent. Low rates of descent prevent the upflow from exceeding the induced flow velocities. High rates of descent result in autorotation or the windmill brake state.
在陡峭的角度下，渦環尾流在直升機下方時的下降速率較慢，而在下降速率較快時則在直升機上方。較低的下降速率防止上升流超過誘導流速。較高的下降速率會導致自轉或風車剎車狀態。
Figure 1-77. Settling with power region
圖 1-77. 具有功率區域的結算
DYNAMIC ROLLOVER
動態翻轉
1-219. A helicopter is susceptible to a lateral-rolling tendency called dynamic rollover. Dynamic rollover can occur on level ground as well as during a slope or crosswind landing and takeoff. Three conditions are required for dynamic rollover—pivot point, rolling motion, and exceed critical angle.
1-219. 直升機容易受到一種稱為動態翻滾的側向翻滾傾向影響。動態翻滾可以在平坦地面上發生，也可以在斜坡或側風著陸和起飛時發生。動態翻滾需要三個條件——支點、翻滾運動和超過臨界角。
Pivot Point
樞紐點
1-220. Dynamic rollover begins when the helicopter starts to pivot around its skid, wheel, or any portion of the aircraft in contact with the ground. When this happens, lateral cyclic control response is more sluggish and less effective than for a free hovering helicopter. This can occur for a variety of reasons including failure to remove a tiedown or skid securing device, the skid or wheel contacts a fixed object while hovering sideward, or the gear is stuck in ice, soft asphalt, or mud. Dynamic rollover may also occur if proper landing or takeoff technique is not used or while performing slope operations. If the gear or skid becomes a pivot point, dynamic rollover is possible if proper corrective techniques are not used.
1-220. 動態翻滾始於直升機開始圍繞其滑橇、輪子或任何與地面接觸的機身部分旋轉。當這發生時，橫向循環控制反應比自由懸停的直升機更遲鈍且效果較差。這可能由於多種原因造成，包括未能移除固定裝置或滑橇固定裝置、滑橇或輪子在側向懸停時接觸固定物體，或齒輪卡在冰、軟瀝青或泥土中。如果未使用正確的著陸或起飛技術，或在執行坡度操作時，也可能發生動態翻滾。如果齒輪或滑橇成為支點，且未使用正確的修正技術，則可能發生動態翻滾。
Rolling Motion
滾動運動
1-221. The rate of rolling motion is vital. As the roll rate increases, the critical angle is reduced. In a fully articulated rotor system, all three control inputs (collective, cyclic, and pedals) can contribute to the rolling motion.
1-221. 滾動運動的速率至關重要。隨著滾轉速率的增加，臨界角度會減小。在一個完全關節化的旋翼系統中，所有三個控制輸入（集體、循環和踏板）都可以對滾動運動產生影響。
Exceed Critical Angle
超過臨界角
1-222. To understand critical angle we must first discuss static rollover angle. Each helicopter has a static rollover angle that, if exceeded, causes the aircraft to rollover. The static angle is based on CG and pivot point. This angle is described as being the point where the aircraft CG is located over the pivot point.
1-222. 要理解臨界角，我們必須首先討論靜態翻滾角。每架直升機都有一個靜態翻滾角，如果超過這個角度，會導致飛機翻滾。靜態角是基於重心（CG）和支點。這個角度被描述為飛機重心位於支點上方的點。
1-223. When a rolling motion is present the dynamic rollover angle is introduced and is called the critical angle. The dynamic angle varies based on the rate of the rolling motion of the helicopter. The greater the rolling motion the earlier (less bank angle) the critical angle is exceeded. If the dynamic rollover angle is exceeded, momentum carries the helicopter through the static rollover angle, regardless of corrections by the aviator.
1-223. 當存在滾轉運動時，引入動態翻滾角，稱為臨界角。動態角度根據直升機的滾轉運動速率而變化。滾轉運動越大，臨界角被超越的時間越早（傾斜角度越小）。如果超過動態翻滾角，動量會使直升機穿過靜態翻滾角，無論飛行員如何修正。
Types
類型
1-224. Certain factors influence dynamic rollover including right skid down, left pedal inputs (single-rotor aircraft), the effects of pilot input (lateral motion) in a rigid rotor aircraft, lateral loading (asymmetrical loading), crosswind, and high roll rates. Smooth and moderate collective inputs are most effective in preventing dynamic rollover as it reduces the rate at which lift/thrust is applied. A smooth and moderate collective reduction is recommended if the onset of dynamic rollover is encountered. There are three main rollover types normally encountered—rolling over on level ground (takeoff), rolling downslope (takeoff or landing) and rolling upslope (takeoff).
1-224. 某些因素會影響動態翻滾，包括右側滑行、左側踏板輸入（單旋翼飛機）、在剛性旋翼飛機中駕駛員輸入的影響（橫向運動）、橫向載荷（不對稱載荷）、側風和高翻滾率。平穩且適度的集體輸入在防止動態翻滾方面最為有效，因為它減少了升力/推力施加的速率。如果遇到動態翻滾的開始，建議平穩且適度地減少集體輸入。通常遇到的三種主要翻滾類型為——在平坦地面上翻滾（起飛）、下坡翻滾（起飛或降落）和上坡翻滾（起飛）。
Rolling Over on Level Ground
在平坦地面上翻滾
1-225. A rollover condition can occur during takeoff from level ground if one skid or wheel is stuck on the ground. As collective pitch is increased, the stuck skid or wheel becomes the pivot point which sets dynamic rollover into motion. A smooth and moderate collective reduction is recommended lowering the aircraft back to the ground until the stuck skid or wheel is free. Then the aircraft may be picked up normally.
1-225. 在從平地起飛時，如果一個滑橇或輪子卡在地面上，則可能會發生翻滾條件。隨著集體桨距的增加，卡住的滑橇或輪子成為支點，導致動態翻滾開始運動。建議平穩且適度地減少集體桨距，將飛機降低回地面，直到卡住的滑橇或輪子脫困。然後，飛機可以正常抬起。
Rolling Downslope
滾動下坡
1-226. A downslope rollover during landing (figure 1-78) occurs when the steepness of the slope causes the helicopter to tilt beyond the lateral cyclic control limits. If the steepness of the slope, a crosswind component, or CG condition exceeds lateral cyclic control limits, the mast forces the rotor to tilt downslope. The resultant rotor vector has a downslope component even with full upslope cyclic applied. To prevent downslope rollover during landing, the aviator slowly descends vertically until ground contact with the upslope skid/wheel occurs. At this point, aircrew members can better assess slope conditions. After stabilizing the helicopter in this position, the aviator smoothly reduces collective until the downslope skid/wheel contacts the ground or cyclic nears lateral limits. If the cyclic is near the lateral limit, the aviator must carefully evaluate remaining distance to ensure enough cyclic travel remains to land without exceeding aircraft limits. If not enough travel remain the aviator should abort the landing, return the aircraft to a hover, and select an area of lesser slope.
1-226. 在著陸過程中發生的下坡翻滾（圖 1-78）是因為坡度的陡峭使直升機傾斜超過橫向循環控制的限制。如果坡度的陡峭程度、側風成分或重心條件超過橫向循環控制的限制，桅杆會迫使旋翼向下坡傾斜。即使在完全施加上坡循環的情況下，產生的旋翼向量仍然具有下坡成分。為了防止在著陸過程中發生下坡翻滾，飛行員應緩慢垂直下降，直到與上坡滑橇/輪子接觸。此時，機組人員可以更好地評估坡度條件。在將直升機穩定在此位置後，飛行員平穩地減少集體桿，直到下坡滑橇/輪子接觸地面或循環接近橫向限制。如果循環接近橫向限制，飛行員必須仔細評估剩餘距離，以確保有足夠的循環行程來著陸而不超過飛機的限制。如果行程不足，飛行員應中止著陸，將飛機返回懸停，並選擇坡度較小的區域。
1-227. A downslope rollover during takeoff (figure 1-78) can occur when the aviator lands the helicopter on too steep a slope, then attempts takeoff. If the upslope skid/wheel begins to rise first, the aviator should lower the collective to prevent a downslope rollover condition. If, with full cyclic applied, the resultant lift of the main rotor is not vertical or directed upslope enough to raise the downslope gear first, and then further takeoff attempts result in the mast causing resultant rotor lift to move further downslope and cause dynamic rollover. The aviator should consider some adjustments before making additional takeoff attempts. These adjustments include awaiting different wind conditions, changing the CG of the helicopter by moving/removing some of the internal load, or contacting a recovery crew.
1-227. 在起飛過程中發生向下坡翻滾（圖 1-78）可能是因為飛行員將直升機降落在過於陡峭的坡度上，然後嘗試起飛。如果上坡的滑橇/輪子首先開始上升，飛行員應該降低集體桿以防止向下坡翻滾的情況。如果在完全施加循環桿的情況下，主旋翼的產生升力不是垂直的或不夠向上坡方向，無法首先抬起下坡的裝置，然後進一步的起飛嘗試會導致主軸使產生的旋翼升力進一步向下坡移動，並導致動態翻滾。飛行員在進行額外的起飛嘗試之前應考慮進行一些調整。這些調整包括等待不同的風況、通過移動/移除一些內部負載來改變直升機的重心，或聯繫救援小組。
Figure 1-78. Downslope rolling motion
圖 1-78. 向下坡的滾動運動
Rolling Upslope
滾動上坡
1-228. An upslope rollover during takeoff (figure 1-79) occurs when the aviator applies too much cyclic into the slope to hold the skid/wheel firmly on the slope. If the aviator improperly applies collective, the helicopter then rapidly pivots upslope around the upslope skid/wheel. To prevent this, the aviator needs to cautiously apply collective while neutralizing the cyclic. When the cyclic is neutral and upslope skid/wheel has no side pressure applied, the aviator performs a vertical lift-off to a hover, then a normal takeoff.
1-228. 在起飛過程中發生的上坡翻滾（圖 1-79）是當飛行員對坡度施加過多的循環控制以保持滑橇/輪子穩固在坡度上時。如果飛行員不當地施加集體控制，直升機將迅速圍繞上坡滑橇/輪子向上傾斜。為了防止這種情況，飛行員需要小心地施加集體控制，同時中和循環控制。當循環控制處於中立狀態且上坡滑橇/輪子沒有側向壓力時，飛行員執行垂直起飛至懸停，然後進行正常起飛。
Figure 1-79. Upslope rolling motion
圖 1-79. 上坡滾動運動
Prevention
預防
1-229. Dynamic rollover usually occurs due to a combination of physical and human factors. Physical factors considered in the prevention of dynamic rollover include main rotor thrust, CG, tail-rotor thrust, crosswind component, ground surface, sloped landing area, and in some aircraft, presence of a low fuel condition which might cause the CG to move upward. The aviator can prevent dynamic rollover by avoiding the physical factors causing it; however, human factors can interfere in the avoidance process. Human factors considered in the prevention of dynamic rollover include—
1-229. 動態翻滾通常是由物理因素和人為因素的結合引起的。防止動態翻滾的物理因素包括主旋翼推力、重心、尾旋翼推力、橫風分量、地面表面、傾斜的降落區域，以及在某些飛機中，可能導致重心上移的低油量狀況。飛行員可以通過避免引起動態翻滾的物理因素來防止動態翻滾；然而，人為因素可能會干擾避免過程。防止動態翻滾的人為因素包括—
Inattention. Dynamic rollover is more likely if the aviator at the controls is inattentive to aircraft position and attitude when lifting off or touching down to the ground, effectively losing situational awareness (SA).
不注意。當操控的飛行員在起飛或著陸時對飛機的位置和姿態不夠注意時，動態翻滾的可能性會增加，實際上失去了情境意識（SA）。
Inexperience. Most dynamic rollover accidents occur while inexperienced aviators are at the controls. The pilot in command (PC) must remain vigilant.
缺乏經驗。大多數動態翻滾事故發生在缺乏經驗的飛行員操控時。指揮飛行員（PC）必須保持警覺。
Failure to take timely corrective action. Timely action must be exercised before a roll rate develops.
未能及時採取糾正措施。必須在滾動比率發展之前採取及時行動。
Inappropriate control input. Applying inappropriate or incorrect control input is the root cause of nearly all dynamic rollovers. If the aviator applies appropriate control input smoothly and carefully, dynamic rollover is avoidable.
不當的控制輸入。不當或不正確的控制輸入是幾乎所有動態翻滾的根本原因。如果飛行員平穩且小心地施加適當的控制輸入，則可以避免動態翻滾。
Loss of visual reference. Loss of visual reference may allow the aircraft to drift unnoticed by the crew. If the aircraft contacts the ground while drifting sideward, rollover can occur. Therefore, if visual reference is lost while the aircraft nears the ground, the aviator should execute a takeoff or go- around using instrument techniques if necessary.
視覺參考的喪失。視覺參考的喪失可能使飛行器在機組人員不知情的情況下漂移。如果飛行器在側向漂移時接觸地面，可能會發生翻覆。因此，如果在飛行器接近地面時失去視覺參考，飛行員應根據需要使用儀器技術執行起飛或繞飛。
Common Errors
常見錯誤
1-230. The following are examples of common errors:
1-230. 以下是常見錯誤的例子：
Aviator fails to detect the aircraft’s lateral motion across the ground before landing.
飛行員在著陸前未能檢測到飛機在地面上的橫向運動。
Aviator makes abrupt cyclic displacements (with or without thrust) in fully articulated rotor systems.
Aviator 在完全關節式旋翼系統中進行突然的循環位移（有或沒有推力）。
Aviator makes large and/or uncoordinated antitorque pedal inputs.
飛行員進行大幅度和/或不協調的反扭力踏板輸入。
Aviator performs slope landing/takeoff maneuvers while using rapidly increasing or decreasing collective control applications.
飛行員在使用快速增加或減少的集體控制應用時執行斜坡著陸/起飛操作。
RETREATING BLADE STALL
退刀停滯
1-231. The retreating blade of a helicopter eventually stalls in forward flight (figures 1-80 through 1-82). As the stall of an airplane wing limits the low speed of a FW aircraft, the stall of a rotor blade limits the high speed of a rotary-wing aircraft. In forward flight, decreasing velocity of airflow on the retreating blade demands a higher AOA to generate the same lift as the advancing blade. Figure 1-80 illustrates the lift pattern at a normal hover with distribution/production of lift evenly spread throughout the rotor disk.
1-231. 直升機的後退葉片在前進飛行中最終會失速（圖 1-80 至 1-82）。就像飛機翼的失速限制了固定翼飛行器的低速一樣，旋翼葉片的失速限制了旋翼飛行器的高速。在前進飛行中，後退葉片上氣流速度的減少需要更高的攻角來產生與前進葉片相同的升力。圖 1-80 顯示了正常懸停時的升力模式，升力的分佈/產生均勻分佈在整個旋翼盤上。
Figure 1-80. Retreating blade stall (normal hovering lift pattern)
圖 1-80. 後退葉片失速（正常懸停升力模式）
1-232. Figure 1-81 illustrates the normal cruise lift pattern where the smaller area of the retreating blade, with its high angles of attack, must still produce an amount of lift equal to the larger area of the advancing blade with its lower angles of attack. This figure shows the advancing blade producing lift throughout its span while the retreating blade is producing lift in only part of its span due to effects of forward airspeed. When forward speed increases, the no-lift areas of the retreating blade grow larger, placing an even greater demand for production of lift on a progressively smaller section of the retreating blade. This smaller section of blade demands a higher AOA until the tip of the blade (area of the highest AOA) stalls.
1-232。圖 1-81 顯示了正常巡航升力模式，其中後退葉片的較小面積，儘管具有較高的攻角，仍必須產生與前進葉片較大面積及其較低攻角相等的升力。該圖顯示前進葉片在其整個跨度上產生升力，而後退葉片僅在其部分跨度上產生升力，這是由於前進空速的影響。當前進速度增加時，後退葉片的無升力區域變得更大，對後退葉片的逐漸減小部分產生升力的需求也隨之增加。這一較小的葉片部分需要更高的攻角，直到葉片的尖端（最高攻角的區域）失速。
Figure 1-81. Retreating blade stall (normal cruise lift pattern)
圖 1-81. 後退葉片失速（正常巡航升力模式）
1-233. Figure 1-82, page 1-65 illustrates the same disk at a critical airspeed with the retreating blade producing less than sufficient lift due to the no-lift area growing larger and effects of tip stall. Tip stall causes vibration and buffeting which spread inboard and aggravate the situation while the aircraft may roll left and nose pitches up. While this may be subtle, it worsens if aft cyclic is not applied or collective is reduced (altitude permitting).
1-233。圖 1-82，頁 1-65 顯示在臨界空速下的同一個旋翼，後退葉片因無升力區域擴大及尖端失速的影響而產生的升力不足。尖端失速會引起振動和顫動，這些現象向內擴散並加劇情況，同時飛機可能向左滾轉，機頭抬起。雖然這可能是微妙的，但如果不施加後循環或減少集體（在高度允許的情況下），情況會惡化。
The effects of retreating blade stall in a tandem-rotor helicopter create a different response. With the forward and aft rotor systems turning in opposite directions, effects of retreating blade stall on the separate rotors tend to counteract themselves. The pitch-up of the nose will be insignificant. Blade stall probably occurs on the aft system first as it operates in the turbulent wake of the forward rotor system. The most likely effect is an increasing vibration which is easily reduced by slowing down and reducing collective pitch (thrust).
在串列旋翼直升機中，後退葉片失速的影響會產生不同的反應。由於前後旋翼系統以相反方向旋轉，後退葉片失速對各自旋翼的影響往往會相互抵消。機頭的仰角變化將不會顯著。葉片失速可能首先發生在後部系統，因為它在前部旋翼系統的湍流尾流中運行。最可能的影響是振動增加，這可以通過減速和降低總揚力（推力）來輕易減少。
Figure 1-82. Retreating blade stall (lift pattern at critical airspeed–retreating blade stall)
圖 1-82. 後退葉片失速（在臨界空速下的升力模式–後退葉片失速）
Conditions Producing Blade Stall
導致刀片失速的條件
1-234. In operations at high forward speeds, the following conditions are most likely to produce blade stall in either single- or tandem-rotor helicopters:
1-234. 在高前進速度的操作中，以下條件最有可能導致單旋翼或雙旋翼直升機的葉片失速：
High blade loading (high gross weight).
高刀片負載（高總重量）。
Low rotor RPM.
低轉子轉速。
High- density altitude.
高密度高度。
High G-maneuvers.
高 G 機動。
Turbulent air.
湍流空氣。
Recovering from blade stall.
從刀片失速中恢復。
1-235. The following steps enable the aviator to recover from retreating blade stall:
1-235. 以下步驟使飛行員能夠從後退葉片失速中恢復：
Reduces collective.
減少集體。
Reduces airspeed.
減少空速。
Descends to a lower altitude (if possible).
下降到較低的高度（如果可能的話）。
Increases rotor RPM to normal limits.
將轉子轉速提高至正常範圍。
Reduces severity of the maneuver.
減少操作的嚴重性。
GROUND RESONANCE
地面共振
1-236. Ground resonance may develop in helicopters having fully-articulated rotor systems when a series of shocks cause the rotor blades in the system to become positioned in unbalanced displacement. If this oscillating condition progresses, it can be self-energizing and extremely dangerous. It can easily cause structural failure. It is most common to three-blade helicopters with landing wheels. The rotor blades in a three-blade system are equally spaced (120 degrees), but are constructed to allow some horizontal lead and lag action. Ground resonance occurs when the helicopter contacts the ground during landing or takeoff (figure 1-83, page 1-66). If one wheel of the helicopter strikes the ground ahead of the others, a shock is transmitted through the fuselage to the rotor. Another shock is transmitted when the next wheel hits. The first shock causes the blades straddling the contact point to jolt out of angular balance. If repeated by the next contact, resonance is established setting up a self-energizing oscillation of the fuselage. Severity of the oscillation increases rapidly. The helicopter can quickly disintegrate without immediate corrective action. Corrective action may consist of an immediate takeoff to a hover or a change in rotor RPM to alleviate the condition and disrupt the pattern of oscillation. In the event
1-236. 當直升機擁有完全關節式旋翼系統時，地面共振可能會發生，當一系列衝擊使系統中的旋翼葉片處於不平衡位移時。如果這種振盪狀態持續進展，它可能會自我增能並極其危險。它很容易導致結構失效。這種情況在配有著陸輪的三葉片直升機中最為常見。三葉片系統中的旋翼葉片均勻間隔（120 度），但設計上允許一些水平的前後動作。地面共振發生在直升機在著陸或起飛時接觸地面時（圖 1-83，頁 1-66）。如果直升機的一個輪子在其他輪子之前接觸地面，衝擊會通過機身傳遞到旋翼。當下一個輪子接觸時，會傳遞另一個衝擊。第一次衝擊使接觸點附近的葉片脫離角平衡。如果下一次接觸重複此過程，則會建立共振，形成機身的自我增能振盪。振盪的嚴重性迅速增加。直升機如果不立即採取糾正措施，可能會迅速解體。 糾正措施可能包括立即起飛至懸停或改變旋翼轉速以緩解狀況並打斷振盪模式。在事件中
takeoff is not an option, all personnel should remain in the aircraft until main rotors have stopped. Ground resonance usually occurs when the aircraft is nearly airborne (80 to 90 percent hover power applied).
起飛不是選項，所有人員應該留在飛機內，直到主旋翼停止。地面共振通常發生在飛機幾乎起飛時（施加 80 到 90%的懸停功率）。
Figure 1-83. Ground resonance
圖 1-83. 地面共振
1-237. The following conditions can cause ground resonance:
1-237. 以下條件可能會導致地面共振：
Defective drag dampers allowing excessive lead and lag and creating angular unbalance.
缺陷的阻尼器允許過度的前後滯後，並造成角度不平衡。
Improperly serviced or defective landing-gear struts.
不當維修或有缺陷的起落架支柱。
Hard landings on one skid or wheel.
在一個滑橇或輪子上硬著陸。
Ground taxiing over rough terrain.
地面滑行於崎嶇地形。
Hesitant or bouncing landings.
猶豫或彈跳著陸。
COMPRESSIBILITY EFFECTS
壓縮性效應
1-238. The effects of compressibility on airfoils can be severe, even to the point of structural failure. Aircraft performance charts will show the regions in which compressibility can occur. Avoiding these flight profiles will avoid blade damage from compressibility effects.
1-238. 壓縮性對翼型的影響可能是嚴重的，甚至可能導致結構失效。飛機性能圖表將顯示壓縮性可能發生的區域。避免這些飛行特徵將能避免因壓縮性影響而造成的葉片損壞。
Compressible and Incompressible Flow
可壓縮流與不可壓縮流
1-239. At low airspeeds, air is incompressible. Incompressible airflow is similar to the flow of water, hydraulic fluid, or any other incompressible fluid. At low speeds, air experiences relatively small changes in pressure with little change in density. However, at high speeds greater pressure changes occur causing compression of air which results in significant changes to air density. This compressible flow occurs when there is a transonic or supersonic flow of air across the airfoil. Because helicopters are being flown at increasingly higher speeds, aviators must learn more about coping with effects of compressible flow.
1-239. 在低空速下，空氣是不可壓縮的。不可壓縮的氣流類似於水、液壓油或任何其他不可壓縮流體的流動。在低速下，空氣的壓力變化相對較小，密度變化也很小。然而，在高速下，壓力變化較大，導致空氣的壓縮，從而使空氣密度發生顯著變化。當空氣在翼型上流動時，這種可壓縮流動會發生在跨音速或超音速的情況下。由於直升機的飛行速度越來越高，飛行員必須學習更多有關應對可壓縮流動影響的知識。
1-240. The major factor in high-speed airflow is the speed of sound. Speed of sound is the rate at which small pressure disturbances move through the air. This propagation speed is solely a function of air temperature. Table 1-4, page 1-67, shows the variation of speed of sound with temperature at various altitudes in the standard atmosphere.
1-240. 高速氣流的主要因素是音速。音速是小壓力擾動在空氣中移動的速率。這種傳播速度僅僅是空氣溫度的函數。表 1-4，第 1-67 頁，顯示了標準大氣中不同高度下音速隨溫度的變化。
Table 1-4. Speed of sound variation with temperature and altitude
表 1-4. 聲速隨溫度和高度的變化
Altitude | Temperature | Speed of Sound | |
Feet | ºF | ºC | Knots |
Sea Level | 59.0 | 15.0 | 661.7 |
5,000 | 41.2 | 5.1 | 650.3 |
10,000 | 23.3 | -4.8 | 638.6 |
15,000 | 5.5 | -14.7 | 626.7 |
20,000 | -12.3 | -24.6 | 614.6 |
25,000 | -30.2 | -34.5 | 602.2 |
30,000 | -48.0 | -44.4 | 589.6 |
35,000 | -65.8 | -54.3 | 576.6 |
40,000 | -69.7 | -56.5 | 573.8 |
50,000 | -69.7 | -56.5 | 573.8 |
60,000 | -69.7 | -56.5 | 573.8 |
C-Celsius F-Fahrenheit | |||
1-241. Compressibility effects are not limited to blade speeds at and above the speed of sound. The aerodynamic shape of an airfoil causes local flow velocities greater than blade speed. Thus a blade can experience compressibility effects at speeds well below the speed of sound because both subsonic and supersonic flows can exist on a blade.
1-241. 壓縮性效應並不僅限於刀片速度達到或超過音速。氣動形狀的翼型會導致局部流速超過刀片速度。因此，刀片在遠低於音速的速度下也能經歷壓縮性效應，因為亞音速和超音速流動都可以存在於刀片上。
1-242. Differences between subsonic and supersonic flow are due to compressibility of supersonic flow. Figure 1-84, page 1-68, compares incompressible and compressible flow through a closed tube. In this example, the mass flow along the tube is constant.
1-242. 亞音速流和超音速流之間的差異是由於超音速流的可壓縮性。圖 1-84，頁 1-68，對比了通過封閉管道的不可壓縮流和可壓縮流。在這個例子中，沿管道的質量流量是恆定的。
Subsonic Incompressible Flow
亞音速不可壓縮流動
1-243. The example of subsonic incompressible flow is simplified because density of flow is constant throughout the tube. As the flow approaches a constriction and streamlines converge, velocity increases as static pressure decreases. A convergence of the tube requires an increasing velocity to accommodate the continuity of flow. Also, as the subsonic incompressible flow enters a diverging section of the tube, velocity decreases and static pressure increases; density remains unchanged.
1-243. 亞音速不可壓縮流的例子被簡化，因為流體的密度在整個管道中是恆定的。當流體接近收縮處且流線匯聚時，速度增加而靜壓降低。管道的收縮需要增加速度以適應流量的連續性。此外，當亞音速不可壓縮流進入管道的擴張段時，速度降低而靜壓增加；密度保持不變。
Supersonic Compressible Flow
超音速可壓縮流動
1-244. The example of supersonic compressible flow is complicated because variations of flow density are related to changes in velocity and static pressure. The behavior of supersonic compressible flow is a convergence causing compression; a divergence causes expansion. Therefore, as the supersonic compressible flow approaches a constriction and streamlines converge, velocity decreases and static pressure increases. Continuity of mass flow is maintained by the increase in flow density accompanying the decrease in velocity. As the supersonic compressible flow enters a diverging section of the tube, velocity increases and static pressure decreases; density decreases to accommodate the condition of continuity.
1-244. 超音速可壓縮流的例子相當複雜，因為流密度的變化與速度和靜壓的變化有關。超音速可壓縮流的行為是收斂造成壓縮；而發散則造成膨脹。因此，當超音速可壓縮流接近收縮處且流線收斂時，速度減少而靜壓增加。質量流的連續性是通過伴隨速度減少而增加的流密度來維持的。當超音速可壓縮流進入管道的發散段時，速度增加而靜壓減少；密度減少以適應連續性的條件。
Figure 1-84. Compressible and incompressible flow comparison
圖 1-84. 可壓縮流與不可壓縮流的比較
Transonic Flow Patterns
超音速流動模式
1-245. In subsonic flight, an airfoil producing lift has local velocities on the surface greater than the free stream velocity. Compressibility effects can then be expected to occur at flight speeds less than the speed of sound. Mixed subsonic and supersonic flow may be encountered in the transonic regime of flight. The first significant effects of compressibility occur in this regime. Compressibility effects on the helicopter increase the power required to maintain rotor RPM and cause rotor roughness, vibration, cyclic shake, and an undesirable structural twisting of the blade.
1-245。在亞音速飛行中，產生升力的翼型在表面上的局部速度大於自由流速度。因此，在飛行速度低於音速時，可以預期會出現可壓縮性效應。在跨音速飛行的範圍內，可能會遇到混合的亞音速和超音速流動。可壓縮性的第一個顯著效應發生在這個範圍內。可壓縮性對直升機的影響增加了維持旋翼轉速所需的功率，並導致旋翼粗糙度、振動、周期性搖晃以及不希望出現的葉片結構扭曲。
1-246. Critical Mach number is the highest blade speed without supersonic airflow. As the critical Mach number is exceeded, an area of supersonic airflow is created. A normal shock wave then forms the boundary between supersonic and subsonic flow on the aft portion of the airfoil surface. The acceleration of airflow from subsonic to supersonic is smooth and without shock waves if the surface is smooth and transition gradual. However, transition of airflow from supersonic to subsonic is always accompanied by a shock wave. When airflow direction does not change, the wave formed is a normal shock wave.
1-246. 臨界馬赫數是指在不產生超音速氣流的情況下，葉片的最高速度。當超過臨界馬赫數時，會產生一個超音速氣流區域。然後，正常激波形成超音速和亞音速流動之間的邊界，位於翼型表面的後部。如果表面光滑且過渡平緩，則氣流從亞音速加速到超音速是平滑的，且不會產生激波。然而，氣流從超音速過渡到亞音速時，總是伴隨著激波。當氣流方向不變時，形成的波是正常激波。
1-247. The normal shock wave is detached from the leading edge of the airfoil and perpendicular to the upstream flow. The flow immediately behind the wave is subsonic. Figure 1-85 illustrates how an airfoil at high subsonic speeds has local supersonic flow velocities. As the local supersonic flow moves aft, a normal shock wave forms slowing the flow to subsonic. As supersonic air passes through shock wave, air density increases, heat is created, velocity of the air decreases, static pressure increases, and boundary layer separation may occur.
1-247. 正常激波從翼型的前緣脫離，並與上游流動垂直。波後的流動為亞音速。圖 1-85 顯示了在高亞音速下，翼型如何具有局部超音速流速。當局部超音速流向後移動時，形成正常激波，使流動減速至亞音速。當超音速空氣通過激波時，空氣密度增加，產生熱量，空氣速度減少，靜壓增加，並可能發生邊界層分離。
Figure 1-85. Normal shock wave formation
圖 1-85. 正常激波形成
1-248. As the shock waves move toward the trailing edge of the airfoil, the aerodynamic center begins to move away from its normal location of 25 percent chord. By the time the shock wave has reached the trailing edge of the airfoil, the aerodynamic center has retreated to the 50 percent chord. This causes the leading edge of the airfoil to be deflected down, which may result in structural failure of the blade (skin deformation or separation).
1-248. 當衝擊波向翼型的後緣移動時，氣動中心開始遠離其正常位置的 25%弦長。當衝擊波到達翼型的後緣時，氣動中心已經退回到 50%弦長。這導致翼型的前緣向下偏轉，可能會導致葉片的結構失效（表皮變形或分離）。
1-249. Because speed of the helicopter is added to the speed of rotation of the advancing blade, the highest relative velocities occur at the tip of the advancing blade. When the Mach number of the advancing blade tip section exceeds the critical Mach number for the rotor blade section, compressibility effects result. The critical Mach number is the free stream Mach number producing the first evidence of local sonic flow. The principle effects of compressibility are large increase in drag and rearward shift of the airfoil aerodynamic center.
1-249. 由於直升機的速度加上前進葉片的旋轉速度，最高的相對速度出現在前進葉片的尖端。當前進葉片尖端部分的馬赫數超過旋翼葉片部分的臨界馬赫數時，會產生可壓縮性效應。臨界馬赫數是產生局部音速流動的第一個證據的自由流馬赫數。可壓縮性的主要影響是阻力的大幅增加和氣動中心的向後移動。
Adverse Compressibility Conditions
不利的可壓縮性條件
1-250. The following operating conditions represent the most adverse compressibility conditions:
1-250。以下操作條件代表最不利的可壓縮性條件：
High airspeed.
高空速。
High rotor RPM.
高轉子轉速。
High gross weight.
高總重。
High- density altitude.
高密度高度。
High G-maneuvers.
高 G 機動。
Low temperature. Speed of sound is proportional to the square root of the absolute temperature; therefore, the aviator more easily obtains sonic velocity at low temperatures.
低溫。聲速與絕對溫度的平方根成正比；因此，飛行員在低溫下更容易達到音速。
Turbulent air. Sharp gusts momentarily increase the blade AOA and thus, lower the critical Mach number to the point where compressibility effects may be encountered on the blade.
湍流空氣。尖銳的陣風瞬間增加了葉片的攻角，因此降低了臨界馬赫數，導致葉片可能遇到壓縮性效應。
Corrective Actions
糾正措施
1-251. Corrective actions are any actions decreasing AOA or velocity of airflow that help the situation. There are similarities in the critical conditions for compressibility and retreating blade stall, with notable exceptions— compressibility occurs at high rotor RPM, and retreating blade stall occurs at low rotor RPM. With the exception of RPM control, the recovery technique is identical for both. Such techniques include decreasing—
1-251. 修正措施是指任何減少迎角或氣流速度的行動，以幫助改善情況。壓縮性和後退葉片失速的臨界條件有相似之處，但有顯著例外——壓縮性發生在高轉子轉速下，而後退葉片失速發生在低轉子轉速下。除了轉速控制外，恢復技術對兩者是相同的。這些技術包括減少—
Blade pitch by lowering collective, if possible.
降低總揚度以調整葉片角度（如果可能的話）。
Rotor RPM.
轉子轉速 (RPM)。
Severity of maneuver.
操作的嚴重性。
Airspeed.
空速。
