초록 ▼

A twin turbine engine helicopter has a two-stage main reduction gearbox, the input stage having a speed reduction ratio exceeding 5.5:1, into an epicyclic gear train second stage ratio about 6:1 for approximately 30:1 or higher overall ratio output to the main rotor. In various embodiments, the firs

A twin turbine engine helicopter has a two-stage main reduction gearbox, the input stage having a speed reduction ratio exceeding 5.5:1, into an epicyclic gear train second stage ratio about 6:1 for approximately 30:1 or higher overall ratio output to the main rotor. In various embodiments, the first stage uses face gears, or bevel gears, with a reduction greater than 5.5:1 and a second stage epicyclic gear train using single or double row helical or spur gears. The first stage gears are straddle mounted in the housing.

대표청구항 ▼

[ What is claimed is:] [1.]1. A combination, comprising:a helicopter having a main rotor;a pair of gas turbine engines mounted to said helicopter, each engine of said pair of gas turbine engines having an engine power output shaft;a pair of nose gearboxes mounted to said helicopter, each nose gearbo

[ What is claimed is:] [1.]1. A combination, comprising:a helicopter having a main rotor;a pair of gas turbine engines mounted to said helicopter, each engine of said pair of gas turbine engines having an engine power output shaft;a pair of nose gearboxes mounted to said helicopter, each nose gearbox of said pair having an input coupled to one of said engine power output shafts, and each nose gearbox of said pair having a power output shaft; anda two stage main reduction gearbox having a first stage power input portion and a second stage power output portion, said power input portion being coupled to said power output shafts of said nose gearboxes, and said power output portion being coupled to said main rotor;said power input portion having a gear reduction first stage speed ratio exceeding 5.5 to 1.