Actuation mechanism for a convertible gas turbine propulsion system

• US 9,580,183 B2
• Filed: 10/11/2011
• Issued: 02/28/2017
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Original Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Inventors: Agrawal, Rajendra K., Reinhardt, Gregory E.
• Primary Examiner(s): SUNG, GERALD LUTHER
• Application Number:
  US13/271,196
• Publication Number:
  US 20120034080A1
• Time in Patent Office: 1,967 Days
• Field of Search: 602/04, 60/391.63, 607/91, 60/391.7, 602/28, 602/29, 602/30, 602/32, 602/263, 251/5, 251/63.5, 137/872, 137/874, 244/6, 244/7.R, 244/7.A, 244/7.B, 244/7.C, 244/17.11, 244/17.13, 244/17.19, 244/17.21
• US Class Current: 1/1
• CPC Class Codes: B64C 27/22 Compound rotorcraft, i.e. aircraft using in flight the features of both aeroplane and rotorcraft
• CPC Class Codes: B64D 33/04 of exhaust outlets or jet pipes exhaust outlets for combustion engines in general F01N; jet pipes or nozzles for jet-propulsion plants per se F02K; plants characterised by the form or arrangement of the jet pipe or nozzle F02K ; attitude, flight direction, or altitude control by jet reaction B64C
• CPC Class Codes: B64D 35/02 specially adapted for specific power plants
• CPC Class Codes: F02C 3/10 with another turbine driving an output shaft but not driving the compressor
• CPC Class Codes: F02C 6/08 the gas being bled from the gas-turbine compressor
• CPC Class Codes: F02C 6/206 the vehicles being airscrew driven
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F02C 9/18 by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages F02C3/113 takes precedence
• CPC Class Codes: F02K 1/08 by axially moving or transversely deforming an internal member, e.g. the exhaust cone
• CPC Class Codes: F02K 3/025 the by-pass flow being at least partly used to create an independent thrust component
• CPC Class Codes: F05D 2220/329 in helicopters

Abstract

A method of powering a rotary-wing aircraft includes selectively coupling and uncoupling a first power turbine to change a power distribution between the rotor system and the secondary propulsion system.

Claims

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.

2. The method as recited in claim 1, further comprising:

selectively permitting ambient air to mix with combustion gases between the second power turbine and the first power turbine.

3. The method as recited in claim 1, further comprising:

varying variable stator vanes of the second power turbine.

4. The method as recited in claim 1, further comprising:

driving a pusher propeller of the secondary propulsion system with the second power turbine.

5. The method as recited in claim 1, further comprising:

coupling the first power turbine and the second power turbine in a high speed flight mode.

6. The method as recited in claim 1, further comprising:

uncoupling the first power turbine and the second power turbine in a low speed flight mode.

7. The method as recited in claim 1, further comprising:

uncoupling the first power turbine and the second power turbine in a hover flight mode.

8. The method as recited in claim 1, further comprising braking windmilling of a pusher propeller of the secondary propulsion system when the second power turbine is coupled to the first power turbine and when the second power turbine is uncoupled from the first power turbine.

9. The method as recited in claim 1, further comprising exhausting gas from the second power turbine when the first and second power turbines are coupled and when the first and second power turbines are uncoupled.

10. The method as recited in claim 1, wherein the first power turbine and the second power turbine are configured to be driven about respective axes that are coaxial.

11. The method of as recited in claim 1, wherein the air is free to move directly from the first power turbine to the second power turbine.

12. The method of as recited in claim 1, including extending and retracting a port to selectively permit ambient air from mixing with exhaust gas from the first power turbine.

13. The method as recited in claim 1, further comprising:

controlling a flow of combustion gases from the first power turbine into a bypass passage to bypass the second power turbine.

14. The method as recited in claim 13, wherein the bypass passage is an annular bypass passage at least partially circumscribing the second power turbine.

15. The method as recited in claim 1, wherein there is a greater pressure differential across the second power turbine when the first and second power turbines are coupled than when the first and second power turbines are uncoupled.

16. A method of powering a rotary-wing aircraft comprising:

selectively coupling and uncoupling a first power turbine and a second power turbine, wherein the first power turbine drives a rotor system, and the second power turbine drives a secondary propulsion system, wherein combustion gases from the first power turbine are free to move through the second power turbine when the first and second power turbines are coupled and when the first and second power turbines are uncoupled, wherein the second power turbine is configured to extract energy from the exhaust gas to drive the secondary propulsion system when coupled to the first power turbine and configured to extract negligible work from the exhaust gas to drive the secondary propulsion system when uncoupled from the first power turbine.

17. A method of powering a rotary-wing aircraft comprising:

selectively coupling and uncoupling a first power turbine and a second power turbine, wherein the first power turbine is configured to drive a rotor system, and the second power turbine is configured to drive a secondary propulsion system, wherein work is extracted from exhaust gases of the first power turbine to drive the second power turbine when the first and second power turbines are coupled, wherein negligible work is extracted from exhaust gases of the first power turbine to drive the second power turbine when the first and second power turbines are uncoupled.

18. The method as recited in claim 17, wherein the second power turbine is driven by the expanding exhaust gases from the first power turbine when the first and second power turbines are coupled, and the second power turbine is not driven when the first and second power turbines are uncoupled.

19. The method as recited in claim 17, wherein a pressure at an upstream end of the second power turbine is greater than a pressure at a downstream end of the second power turbine when the first and second power turbines are coupled, and the pressure at the upstream end is substantially equal to the pressure at the downstream end when the first and second power turbines are uncoupled.