FAA Flight Instructor Airplane (FIA)Aerodynamics and Principles of FlightHard
During a fully developed spin, the descending wing has a higher angle of attack than the ascending wing and produces less lift and more drag, while the ascending wing produces relatively more lift and less drag. This imbalance sustains the rotation without further pilot input. What is this self-sustaining rotational condition called?
- AOverbanking tendency
- BAdverse yaw
- CDutch roll
- DAutorotation
Show answer & explanationAnswer & explanation
Correct answer: D. Autorotation
Autorotation is the self-sustaining roll and yaw motion that occurs in a fully developed spin. The descending wing's higher AOA (often beyond critical AOA, producing less lift and more drag) versus the ascending wing's lower AOA (producing more lift and less drag) creates an aerodynamic couple that perpetuates the rotation until control inputs disrupt the imbalance.
Why the other options are wrong
- A. Overbanking tendency occurs in a steep, coordinated turn due to differing wingtip speeds, not in a spin.
- B. Adverse yaw is caused by differential aileron drag during a coordinated turn entry, not spin dynamics.
- C. Dutch roll is an oscillatory yaw-roll coupling in normal flight, unrelated to spin autorotation.
Autorotation (Spin)
The self-sustaining rolling and yawing motion of a fully developed spin, driven by the descending wing's higher AOA/more drag/less lift versus the ascending wing's lower AOA/more lift/less drag.
- Occurs after a stall combined with yaw
- Continues until control inputs break the lift/drag imbalance
- Recovery requires opposite rudder, forward elevator/reduced back pressure, and neutral ailerons
Memory trick: Autorotation = the spin's engine that keeps itself turning