Abstract: A helicopter (10) incorporates apparatus (15) for mounting a device such as an aerial or a sight (14) above a main sustaining rotor (13). The apparatus comprises first and second ring gears (16, 20) located respectively below and above the rotor, the first gear (16) being supported from helicopter structure (17) concentrically of an axis of rotation (11) of the sustaining rotor, support means (37) supporting the second gear and the device above the rotor in a manner permitting relative rotation of the rotor hub, and synchronizing means (25) rotationally fixed to the rotor hub and meshing with the first and second gears to retain the device stationary during rotation of the rotor system. In a preferred embodiment, positioning means are provided to rotate the first gear in either direction of rotation whereby the device can be rotated and selectively positioned independently of the rotation of the rotor.

Abstract: A freewheel device for connecting a power input to a selected one of a plurality of outputs so as to transmit rotary motion in one direction of rotation and to over-run when the speed of the selected one of the outputs exceeds that of the input, includes a neutral condition in which the input is rotationally disengaged from any of the outputs. In a described embodiment, the freewheel device comprises a plurality of rollers retained circumferentially adjacent one end of an axially movable shaft in operative association with a plurality of wedge-shaped portions formed on the shaft, axial movement of the shaft serving to engage the rollers between the wedge-shaped portions and, selectively axially spaced-apart internal, cylindrical surfaces formed on each of the outputs and on a rotatable support.The freewheel device finds particular application in the transmission system of multi-engined helicopters.

Abstract: A helicopter rotor includes a powered blade fold mechanism adapted to move a rotor blade between a spread operational position and a folded position and at least one lock pin (17) to lock the blade in its spread position. The mechanism includes a rotary power source (21) and a mechanical linkage (23, 25) having an over-center position and adapted so that energization of the power source in one direction moves the linkage through the over-center position to withdraw the lock pin and fold the blade, and energization in the other direction moves the blade to the spread position and re-inserts the lock pin automatically as the linkage moves back through its over-center position. Lock means may be provided to lock the blade in pitch and, in one embodiment particularly adapted for use in an articulated rotor, the lock means includes pitch, flap and lag locks.