Patent ID: 9580183
Date: 2017-02-28
CPC Classifications: B64C,B64D,F02C,F02K,F05D

Claim:
1. A method of powering a rotary-wing aircraft, comprising: selectively coupling and uncoupling a first power turbine which drives a rotor system and a second power turbine which drives a secondary propulsion system to change a power distribution between the rotor system and the secondary propulsion system, wherein exhaust gas from the first power turbine is free to move to the second power turbine when the first and second power turbines are both coupled and uncoupled, wherein work is extracted from the second power turbine to drive the secondary propulsion system when coupled to the first power turbine and negligible work is extracted from the second power turbine to drive the secondary propulsion system when uncoupled from the first power turbine.