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US 10,370,094 B2Granted
Multi-speed gearbox for tail rotor of a compound helicopter
AssigneeSikorsky Aircraft Corporation
InventorTodd A. Garcia
Life of this patent
Estimating the term…
Abstract
A rotary wing aircraft and method of operating a tail drive system thereof, wherein the tail drive system includes a gearbox that contains a first transmissive device and a second transmissive device in parallel, each transmissive device having an input operatively connected to a first shaft that is powered by the main rotor drive system. The first and second transmissive devices each have an output operatively connected to a second shaft that drives the secondary rotary device.
Claims11
A rotary wing aircraft, comprising:
- a main drive system having a main rotary system which is rotatable to produce main thrust;
- a main rotor drive system which drives the main drive system to rotate the main rotary system at a main rotational speed to produce the main thrust;
- and
- a tail drive system having a first shaft operatively connected to and driven by the main rotor drive system, the tail drive system further comprising a gearbox that receives the first shaft, the gearbox further containing:
- a first transmissive device, the first shaft operatively connected to an input of the first transmissive device;
- a second transmissive device, the second transmissive device arranged in parallel with the first transmissive device, the first shaft operatively connected to an input of the second transmissive device;
- a second shaft operatively connected to an output of the first transmissive device and to an output of the second transmissive device;
- a first gear reduction arranged in connection with the first shaft, the first gear reduction having a first reduction ratio;
- and
- a second gear reduction arranged in connection with the second shaft, the second gear reduction having a second reduction ratio;
- and
- a secondary rotary device operatively connected to the second shaft so as to be driven at a tail rotational speed to produce a tail thrust, the speed of the second shaft being variable according to a selective engagement of the first and second transmissive devices, wherein the speed of the second shaft is controlled by a first gear reduction in a first mode and controlled by the second gear reduction in a second mode.
9 more elements
A method of operating a rotary aircraft having a multi-speed tail drive system, comprising:
- generating input torque at a main rotor drive system to drive a main rotor system to produce main thrust;
- transferring the input torque to a tail drive gearbox, the gearbox containing a freewheel unit and a transmissive device arranged in parallel to change a speed of a secondary rotary device;
- and
- manipulating the transmissive device to control the speed of the secondary rotary device to produce a secondary thrust, wherein manipulating the transmissive device allows the secondary rotary device to operate at two speeds relative to the input torque, a first speed being determined by a first gear reduction and a second speed being determined by a second gear reduction.
1 more element
Dependencies are inferred from the claim text.