Compare and contrast spin recovery procedures of a F18 and a

Compare and contrast spin recovery procedures of a F-18 and a BE20 king air. What makes the recoveries different for each aircraft?

Solution

>> A King Air is extremely difficult to recover, as are most light twins, due to the angular momentum of the engines out on the wings.

>> Early on, the Navy lost several F-18s due to flat spins. They then studied the phenomenon at Pax River, and in the end Bill Bihrle found out that the elevator shields airflow from the two vertical tails of the F-18 when the stick is pushed, but moves out of the way when the stick is pulled full aft. You have to know that the elevator of the F-18 is a full-flying surface, and the movement range is from -20° to +70°. At +70° it is almost in line with the airflow in a flat spin, and now the vertical tails are no longer in the wake of the elevator. They now can reduce the high yaw rate, which in turn reduces the high pitch-up moment of the rotating fuselage. With the lower inertial pitch-up moment, the elevator then has to be moved back to neutral, and the drag from wing and elevator is enough to pitch the aircraft fully down and out of the spin.

Naturally stable flying wings never enter a flat spin; their spin modes are all fairly steep due to the lack of a strong inertial moment from the lengthwise distribution of masses.