Gas turbine engine with noise attenuating variable area fan nozzle

1. A rotary-wing aircraft comprising:

a rotor system;

a secondary propulsion system transverse to said rotor system;

a gas generator operable to generate combustion gases;

a first power turbine to receive said combustion gases from said gas generator, said first power turbine operable to drive said rotor system;

an outer duct downstream of said first power turbine;

an inner duct at least partially within said outer duct to define a bypass passage between said inner duct and said outer duct; and

a retractable port movable between a closed position and an open position to selectively control flow of said combustion gases into said bypass passage to change a power distribution between said rotor system and said secondary propulsion system, wherein said secondary propulsion system is a pusher propeller.

2. The rotary-wing aircraft as recited in claim 1 , wherein said retractable port is defined between a forward duct and said inner duct, said forward duct defined about said gas generator.

3. The rotary-wing aircraft as recited in claim 1 , wherein said retractable port is pneumatically operated by compressed bleed air sourced from said gas generator.

4. The rotary-wing aircraft as recited in claim 1 , further comprising a gearbox to drive said rotor system, said gearbox driven by said first power turbine.

5. The rotary-wing aircraft as recited in claim 1 , wherein said open position windmills said pusher propeller.

6. The rotary-wing aircraft as recited in claim 1 , wherein said rotor system is a coaxial contra-rotating rotor system.

7. A rotary-wing aircraft comprising:

a rotor system;

a secondary propulsion system transverse to said rotor system;

a first power turbine operable to drive said rotor system;

a second power turbine downstream of said first power turbine, said second power turbine operable to drive said secondary propulsion system; and

an exhaust system to couple and uncouple said second power turbine and said first power turbine to change a power distribution between said rotor system and said secondary propulsion system, wherein said secondary propulsion system is a pusher propeller.

8. The rotary-wing aircraft as recited in claim 7 , wherein said rotor system is a coaxial contra-rotating rotor system.

9. The rotary-wing aircraft as recited in claim 7 , wherein said exhaust system defines a pressure chamber between said second power turbine and said first power turbine.

10. The rotary-wing aircraft as recited in claim 9 , further comprising a retractable port in communication with said pressure chamber to effect said pressure change.

11. The rotary-wing aircraft as recited in claim 9 , wherein said exhaust system defines a bypass passage in selective communication with said first power turbine.

12. The rotary-wing aircraft as recited in claim 7 , wherein said second power turbine includes variable stator vanes.

13. The rotary-wing aircraft as recited in claim 7 , wherein said exhaust system further comprises:

a forward duct defined about a gas generator to communicate combustion gases from said gas generator to said first power turbine;

an outer duct downstream of said first power turbine;

an inner duct downstream of said second power turbine, said inner duct at least partially within said outer duct to define a bypass passage between said inner duct and said outer duct; and

a retractable port between said forward duct and said inner duct, said retractable port movable between a closed position and an open position, said closed position operable to form a continuous duct for said first power turbine and said second power turbine, and said open position operable to communicate at least a portion of said combustion gases from said first power turbine into said bypass duct.

14. A rotary-wing aircraft comprising:

a rotor system;

a secondary propulsion system transverse to said rotor system;

a gas generator operable to generate combustion gases;

a first power turbine to receive said combustion gases, said first power turbine operable to drive said rotor system;

an outer duct downstream of said first power turbine;

a second power turbine downstream of said first power turbine, said second power turbine operable to drive said secondary propulsion system;

an inner duct within said outer duct to define a bypass passage between said inner duct and said outer duct; and

a retractable port movable between a closed position and an open position to selectively control flow of said combustion gases from said first power turbine into said bypass passage and change a power distribution between said rotor system and said secondary propulsion system, wherein said secondary propulsion system is a pusher propeller.

15. The rotary-wing aircraft as recited in claim 14 , wherein said gas generator includes a gas generator turbine, said gas generator turbine, said first power turbine and said second power turbine along a common axis.

16. The rotary-wing aircraft as recited in claim 15 , wherein said gas generator turbine is coupled to a compressor section.

17. The rotary-wing aircraft as recited in claim 6 , wherein said coaxial contra rotating rotor system is configured to be driven to produce upward lift.

18. The rotary-wing aircraft as recited in claim 8 , wherein said coaxial contra rotating rotor system is driven to produce upward lift.

19. The rotary-wing aircraft as recited in claim 1 , wherein said outer duct is entirely downstream of said first power turbine.

20. The rotary-wing aircraft as recited in claim 1 , wherein the retractable port in the open position is operable to communicate at least a portion of said combustion gases from said first power turbine into said bypass passage.