Abstract: An improved tilting rotor aircraft, a control system for an elongated shaft, and a method of controlling an elongated shaft are provided. Sensors are utilized to detect an amount of twist on a flexible and elongated shaft. A controller receives the signal and generates a command signal. A plurality of actuators receive the command signals and compensate for the twist in the flexible and elongated shaft.

Abstract: A improved tilt rotor aircraft comprising an airframe, at least one wing member coupled to the airframe, and at least one tilt rotor assembly carried by the at least one wing member. The tilt rotor assembly is actuated by a conversion actuator. The improved tilt rotor aircraft includes a low-height tunable downstop assembly for absorbing oscillatory vibration loads, such as pitch loads and yaw loads. The low-height tunable downstop assembly comprises a pivotable striker assembly having an adjustable stiffness, and a cradle assembly adapted to releasably receive the striker assembly. The striker assembly is attached to the tilt rotor assembly and the cradle assembly is attached to the wing member. A plurality of sensor modules are bonded to the cradle assembly. The sensor modules include a plurality of strain gages arranged to sense shear strain in the cradle assembly. The sensor modules are electrically coupled to sensor circuits and flight control computers.