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4，飞行原理

(1)How can the stability of the atmosphere be determined?

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A．Ambient temperature lapse rate.

B．Atmospheric pressure at various levels. C．Surface temperature/dewpoint spread.

正确答案：A

(2)____ prevents air flowing directly from the high pressure area to low pressure area when air moves in a level direction.

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A．Friction force.

B．Inertial centrifugal force. C．Coriolis deflecting force.

正确答案：C

(3)One purpose of high-lift devices is to

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A．increase the load factor.

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B．delay stall. C．increase airspeed.

正确答案：B

(4)The primary purpose of high-lift devices is to increase the

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A．L/Dmax.

B．Lift at low speeds. C．Drag and reduce airspeed.

正确答案：B

(5)Airflow separation over the wing can be delayed by using vortex generators

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A．directing high pressure air over the top of the wing or flap through slots and making the wing surface smooth.

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B．directing a suction over the top of the wing or flap through slots and making the wing surface smooth.

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C．making the wing surface rough and/or directing high pressure air over the top of the wing or flap through slots.

正确答案：C

(6)Describe dynamic longitudinal stability.

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A．Motion about the longitudinal. B．Motion about the lateral axis. C．Motion about the vertical axis.

正确答案：B

(7)Identify the type stability if the aircraft attitude remains in new position after the controls have been neutralized.

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A．Negative longitudinal static stability

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B．Neutral longitudinal dynamic stability C．Neutral longitudinal static stability

正确答案：C

(8)Identify the type stability if the aircraft attitude tends to move farther from its original position after the controls have been neutralized.

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A．Negative static stability B．Positive static stability C．Negative dynamic stability

正确答案：A

(9)Identify the type stability if the aircraft attitude tends to return to its original after the controls have been neutralized.

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A．Positive dynamic stability. B．Positive static stability. C．Neutral dynamic stability.

正确答案：B

(10)What is a characteristic of longitudinal instability?

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A．Pitch oscillations becoming progressively greater.

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B．Bank oscillations becoming progressively greater.

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C．Aircraft constantly tries to pitch down.

正确答案：A

(11)If the airplane attitude remains in a new position after the elevator control is pressed forward and released, the airplane displays

? ? ?

A．neutral longitudinal static stability. B．positive longitudinal static stability. C．neutral longitudinal dynamic stability.