초록 ▼

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

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.

대표청구항 ▼

An improvement in a helicopter having a substantially constant speed engine comprising: a main speed rotor system; a tail thrust means for generating at least a side thrust on said helicopter; a first multiple speed transmission having its input coupled to said engine and its output coupled to a sel

An improvement in a helicopter having a substantially constant speed engine comprising: a main speed rotor system; a tail thrust means for generating at least a side thrust on said helicopter; a first multiple speed transmission having its input coupled to said engine and its output coupled to a selected one of said main rotor system and said tail thrust means; and a second multiple speed transmission having an input coupled to said engine, said first multiple speed transmission having an output coupled to said selected one of said main rotor system and tail thrust means, said second multiple speed transmission having an output coupled to the other one of said main rotor system and tail thrust means, whereby rotational speed of said selected one of said main rotor system and said tail thrust means is driven with an arbitrarily selected rotational speed in order to optimize the flight envelope of said helicopter.