A continuously-variable transmission (CVT) assembly is employed for transmitting a torque from an external power-source The CVT includes a variable-diameter input pulley and a variable-diameter output pulley, each having a respective range of adjustment The CVT also includes a continuous torque-transmitting element extending between the variable-diameter input pulley and the variable-diameter output pulley, and thereby operatively connecting the input pulley to the output pulley The CVT additionally includes a first elastic element having a first zero stiffness over the range of adjustment of the variable-diameter input pulley and configured to apply a first constant spring clamping force via the input pulley to the continuous torque-transmitting element Furthermore, the CVT includes a second elastic element having a second zero stiffness over the range of adjustment of the variable-diameter input pulley and configured to apply a second constant spring clamping force via the output pulley to the continuous torque-transmitting element

Continuously-variable transmission

An aircraft including an airframe having a fuselage which extends longitudinally, and having fixed wings including a main wing, a horizontal tail wing and a vertical tail wing. A propeller-rotor torque transmission has a bevel gear which transmits the rotation of an input shaft simultaneously to a propeller shaft and to a rotor shaft. An engine gearbox supplies the above-mentioned input shaft with rotationalal motive power. The aircraft further includes a propeller collective pitch controller, a rotor collective pitch controller, an engine power controller which controls the output of the above-mentioned engine gearbox for the purpose of changing the rotational speed of the input shaft, and a flight control system having a directional (yaw) control system which controls the flight direction of the aircraft by controlling the positions of the above-mentioned control surfaces.

Aircraft and torque transmission

A helicopter has two engines adapted to drive a main sustaining rotor and a plurality of auxiliary propulsion means through a transmission system that is selectively operable to vary the relative speeds of rotation of the sustaining rotor and the auxiliary propulsion means depending upon operating conditions.

Helicopter rotor speed changing transmission

A variable speed tilt rotor system and method for operating such a system are provided which allow the rotor to be operated at an optimal angular velocity in revolutions per minute (RPM) minimizing the power required to turn the rotor thereby resulting in performance efficiency improvements, reduction in noise, and improvements in rotor, transmission and engine life. The system and method provide for an increase in endurance and range. The system and method also provide a substantial improvement in performance during take-off, hover and maneuver. All such improvements are valid in helicopter mode when the helicopter is supported by rotor vertical lift, in airplane mode when the helicopter is supported by wing lift and the rotor is tilted forward to provide propulsive thrust and in conversion from helicopter mode to airplane mode.

Optimum speed tilt rotor

An engine accessory system (62) for a gas turbine engine (10) includes a first accessory component (AC) mountable to an accessory gearbox (60) along a first accessory axis (b) transverse to a layshaft axis of rotation (L). A second accessory component (AC) is mountable along a second accessory axis (c) transverse to the layshaft axis of rotation (L), the first and second accessory axis (b, c) defining a V-orientation.

Accessory gearbox with internal layshaft

A fast forward flight helicopter is provided with a multiple speed helicopter rotor transmission. The transmission allows a variation in main rotor RPM or tail rotor RPM or both, dependent upon the desired flight conditions, while maintaining satisfactory lift and performance. With this means, noise is controlled without loss of aerodynamic performance. In one embodiment a helicopter is provided with a transmission for interconnecting the power input shaft through the main rotor shaft and tail rotor shaft in common. The transmission employed is a planetary gear transmission. A brake means is provided for clutching the planetary gear transmission from a first and second transmission speed so that power is continuously delivered, and shifting is accomplished in a smooth manner, thereby allowing the helicopter to remain in smooth flight. In another embodiment the main rotor is driven through the planetary gear transmission and the tail rotor is directly driven. In another embodiment a no-tail-rotor (NOTAR) helicopter is driven by the planetary gear system with the main rotor system being directly driven.

Richard E. Moore

Papers

Helicopter rotor transmission systems