China Civil UAV Theory Questions — Questions 942–951

Study note: extending the flaps or the landing gear calls for more throttle; retracting them calls for less. The question specifies constant speed, so the engine thrust originally equals drag. When the landing gear is extended, drag increases. To keep the forces balanced, the engine thrust must also increase, so the pilot must increase throttle.

Study note: extending the flaps or the landing gear calls for more throttle; retracting them calls for less. The question specifies constant speed, so the engine thrust originally equals drag. After the flaps are retracted, drag decreases. To keep the forces balanced, the pilot must decrease throttle to reduce thrust.

The question specifies constant speed, so the engine thrust originally equals drag. When the landing gear is retracted, drag decreases. To keep the forces balanced, the engine thrust must also decrease, so the pilot must decrease throttle.

After the flaps are extended, drag increases and flight speed decreases.

In flight, the landing gear produces pressure drag, friction drag, interference drag, and similar drag. Extending the landing gear increases the aircraft's total drag.

When the flaps are retracted, drag decreases and flight speed increases.

In flight, the landing gear produces pressure drag, friction drag, interference drag, and similar drag. Retracting the landing gear decreases the aircraft's total drag.

Flight sticks and external control boxes: (1) The flight stick is the conventional operation mode, similar to a manned aircraft, and includes attitude remote control and control-surface remote control functions. In actual flight, the stick's control-surface remote control function is very rarely used. (2) The external control box works like a model-aircraft transmitter and includes attitude remote control and control-surface remote control functions.

The engine manufacturer does not affect flight safety, so it need not be checked. Further reading, pre-takeoff powerplant checks: (1) engine fuel quantity check; (2) engine fuel line check; (3) engine external looseness check; (4) idle RPM, vibration, and stability check after engine start; (5) high-power RPM and vibration check; (6) engine throttle, high/low fuel needles, and control cable (rod) check; (7) engine throttle-following check; (8) for micro UAVs, engine stability checks in different attitudes; (9) for electric motors, forward/reverse rotation check; (10) interference check between the powerplant after start and other systems.

The airframe's paint scheme does not affect flight safety, so it need not be checked. Further reading, pre-takeoff airframe checks: (1) airframe appearance and symmetry check; (2) airframe weighing and center-of-gravity check; (3) control-surface structure and connection check; (4) takeoff (launch) and landing (recovery) device check; (5) propeller direction and tightness check.