xoáy Khi các cánh quạt xoay và nâng được sản xuất, áp suất cao được hình thành dưới áp lực phiến và thấp ở trên lưỡi dao. Các cạnh sắc nét dấu của lưỡi dao giữ cho không khí áp suất cao từ khu vực áp suất thấp trên hầu hết các lưỡi dao, ngoại trừ đầu, nơi không có gì ngăn cản không khí từ uốn lên từ đáy lưỡi dao lên trên. | HELICOPTER AERODYNAMICS WORKBOOK CHAPTER 3 THIS PAGE INTENTIONALLY LEFT BLANK HELICOPTER POWERED FLIGHT ANALYSIS 3-21 CHAPTER 3 HELICOPTER AERODYNAMICS WORKBOOK CHAPTER THREE REVIEW ANSWERS 1. increase 2. The rotor systems turn in opposite directions canceling the torque effect. 3. increase . . . decreasing 4. weather vaning . . . vertical stabilizer 5. Tail rotor thrust causes a right drift requiring left cyclic for vertical takeoffs and landings. This is why the right skid lifts off first and touches down last. 6. virtual axis 7. mechanical axis 8. center of gravity 9. mechanical axis . . . acceleration 10. One cannot tilt the rotor system enough to allow the virtual axis to offset the extremely displaced center of gravity. 11. phase lag 12. dissymmetry of lift 13. blowback . . . up . . . dissymmetry of lift . . . phase lag 14. mass flow of air . . . induced velocity 15. induced velocity 16. centrifugal force . . . blade lift 3-22 HELICOPTER POWERED FLIGHT ANALYSIS CHAPTER FOUR TERMINAL OBJECTIVE Upon completion of this chapter the student will be able to describe and analyze the aerodynamics associated with unpowered rotary flight. ENABLING OBJECTIVES Define autorotation. Draw and label a blade element diagram for autorotation. Define pro-autorotative force. Define anti-autorotative force. State the three phases required to transition from powered to unpowered flight. State the effects of a flare in autorotation. State the variables that affect autorotative descent. State the purpose of the height-velocity diagram. AUTOROTATION .
