초록 ▼

A gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor

A gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor speed.

대표청구항 ▼

What is claimed is: 1. A main gearbox system for a rotary-wing aircraft which drives a main rotor assembly and a tail rotor system comprising: a main gear coaxial with a main rotor shaft of the main rotor assembly; an input shaft driven at an engine speed; a tail-take-off shaft driven by said input

What is claimed is: 1. A main gearbox system for a rotary-wing aircraft which drives a main rotor assembly and a tail rotor system comprising: a main gear coaxial with a main rotor shaft of the main rotor assembly; an input shaft driven at an engine speed; a tail-take-off shaft driven by said input shaft, said tail-take-off shaft driven about a tail-take-off shaft axis of rotation; a reduction stage shaft driven through said tail-take-off shaft to drive said main gear, said reduction stage shaft driven about a reduction stage shaft axis of rotation which extends across at least a portion of said main gear; a variable speed system upstream of said reduction stage shaft and downstream of said tail-take-off shaft, said variable speed system operable to drive said main gear speed at a variable speed relative to the engine speed; and a tail rotor system driven through said tail-take-off shaft, said tail rotor system driven at a constant speed relative to the engine speed. 2. The system as recited in claim 1, wherein said variable speed system is mounted to a gear which drives said reduction stage shaft. 3. The system as recited in claim 2, wherein said gear rotates about said reduction stage shaft axis of rotation. 4. The system as recited in claim 3, wherein said gear is coupled to said tail-take-off shaft. 5. The system as recited in claim 1, further comprises at least one spiral bevel gear mounted along said reduction stage shaft, said at least one spiral bevel gear operable to drive a reduction stage gear train. 6. The system as recited in claim 3, wherein said reduction stage gear train is operable to drive said main gear. 7. The system as recited in claim 1, wherein said tail-take-off shaft and said reduction stage shaft are generally parallel. 8. The system as recited in claim 1, wherein said input shaft, said tail-take-off shafi and said reduction stage shaft are generally parallel. 9. The main gearbox as recited in claim 1, wherein said tail-take-off shaft is operable to drive a tail rotor transmission shaft about a tail rotor transmission shaft axis of rotation, said tail rotor transmission shaft operable to drive said tail rotor system. 10. The main gearbox as recited in claim 9, wherein said tail-take-off shaft is in meshing engagement with a tail rotor input shaft driven about a tail rotor input axis of rotation, said tail rotor input axis of rotation transverse to said tail-take-off shaft axis of rotation and said tail rotor transmission shaft axis of rotation. 11. The system as recited in claim 1, wherein said tail rotor system comprises an anti-torque rotor. 12. The system as recited in claim 1, wherein said tail rotor system comprises a translational thrust system.