The Bell-Boeing V-22 Osprey Tiltrotor is both an airplane and helicopter. Its advantage is the ability to rotate its engine 90° from a vertical position for takeoffs and landings and

then to switch the engines to a horizontal position for cruising as an airplane. The altitude control system in the helicopter mode is shown in the block diagram. (a) Determine the root locus as K varies and determine the range of K for a stable system. (b) For K = 280, find the actual y(t) for a unit step input r(t)and all the transient response characteristics.