Rotary adjustable exhaust nozzle
View Patent ↗An exhaust nozzle includes an exhaust duct with an outlet and a row of radial apertures upstream therefrom. A radial frame surrounds the duct upstream from the apertures. A row of flaps are hinged to the frame to selectively cover and uncover the apertures for controlling exhaust flow discharged therethrough. An arcuate unison bar surrounds the duct adjacent to the frame and includes circumferentially spaced apart cams engaging corresponding cam followers affixed to the flaps. An actuator is joined to the bar for selective rotation thereof between opposite first and second directions to pivot open and closed the flaps atop the apertures.
1. A gas turbine engine exhaust nozzle comprising:
an exhaust duct having an outlet at an aft end thereof for discharging exhaust flow, and including a row of radial apertures spaced upstream from said outlet;
a radial frame extending circumferentially around said duct and spaced forward from said apertures;
a plurality of flaps hinged at upstream ends thereof to said frame to selectively cover and uncover said apertures for controlling exhaust flow discharge therethrough, and each flap includes a cam follower affixed thereto;
an arcuate unison bar mounted circumferentially around said duct adjacent to said frame, and including a plurality of cams spaced circumferentially apart in engagement with corresponding ones of said cam followers affixed to said flaps and
an actuator joined to said bar for selectively rotating said bar in a first direction to pivot open said flaps, and in an opposite second direction to pivot closed said flaps to cover said apertures.
2. A nozzle according to claim 1 wherein each of said flaps is pivotally joined to said frame by a pair of hinges, and includes a control arm extending radially outwardly therefrom to position said cam follower along said unison bar.
3. A nozzle according to claim 2 wherein each of said cams comprises a ramp extending circumferentially along a portion of the outer perimeter of said bar, and varies in radial height from low to high, with low cam height positioning said cam follower radially inwardly to pivot open said flaps radially outwardly, and high cam height positioning said cam followers radially outwardly to pivot closed said flaps radially inwardly.
4. A nozzle according to claim 3 wherein said cams include an up-step at the base of said ramp at said low cam height, and a down-step at the top of said ramp at said high cam height.
5. A nozzle according to claim 3 wherein said unison bar is mounted to said duct by a plurality of outer and inner wheels spaced circumferentially apart.
6. A nozzle according to claim 5 wherein said outer and inner wheels include grooves being complementary with said bar for radially and axially trapping said bar to limit motion thereof to circumferential rotary movement around said duct.
7. A nozzle according to claim 3 wherein said actuator is joined to a proximal end of said bar, and an opposite distal end of said bar is free.
8. A nozzle according to claim 7 wherein said actuator includes an output rod joined to said proximal end of said bar, and is configured to extend said rod to rotate said bar in said first direction, and to retract said rod to rotate said bar in said second direction.
9. A nozzle according to claim 3 wherein said cam follower comprises a cam roller mounted to a distal end of said control arm for each of said flaps.
10. A nozzle according to claim 9 wherein said cam roller is axially elongate to maintain rolling contact with said unison bar as said flaps pivot open and closed in response to rotary movement of said unison bar around said duct.
11. A nozzle according to claim 3 wherein said cam followers are unrestrained radially outwardly from said unison bar, and said flaps are hinged to said frame to permit pressure of said exhaust flow inside said duct to power open said flaps as said unison bar is rotated in said first direction.
12. A nozzle according to claim 3 wherein said unison bar further comprises a plurality of retainer tracks spaced above respective ones of said cams to trap said cam followers radially inwardly.
13. A nozzle according to claim 3 further comprising a plurality of springs mounted between respective ones of said cam followers and said exhaust duct to restrain said cam followers radially inwardly.
14. A nozzle according to claim 3 further comprising an outer duct surrounding said exhaust duct to form a bypass channel extending aft from said apertures and terminating at an auxiliary outlet.
15. A gas turbine engine exhaust nozzle comprising:
an inner exhaust duct having a main outlet at an aft end thereof for discharging exhaust flow, and including a row of radial apertures spaced upstream from said main outlet;
an outer duct surrounding said inner duct to form a bypass channel extending aft from said apertures and terminating at an auxiliary outlet;
a radial frame extending radially around said inner duct from said apertures;
a plurality of flaps hinged at upstream ends thereof to said frame to selectively cover and uncover said apertures for controlling exhaust flow discharge therethrough, and each flap includes a cam follower affixed thereto;
an arcuate control bar mounted circumferentially around said inner duct adjacent to said frame, and including a plurality of cams spaced circumferentially apart in engagement with corresponding ones of said cam followers affixed to said flaps; and
an actuator joined to said bar for selectively rotating said bar in a first direction to pivot open said flaps in unison, and in an opposite second direction to pivot closed said flaps in unison to cover said apertures.
16. A nozzle according to claim 15 wherein:
each of said flaps is pivotally joined to said frame by a pair of hinges, and includes a control arm extending radially outwardly therefrom to position said cam follower along said control bar; and
said control bar is mounted to said inner duct by a plurality of outer and inner wheels spaced circumferentially apart.
17. A nozzle according to claim 16 wherein:
said cam follower comprises a cam roller mounted to a distal end of said control arm for each of said flaps; and
each of said cams comprises a ramp extending circumferentially along a portion of the outer perimeter of said bar, and varies in radial height from low to high, with low cam height positioning said cam rollers radially inwardly to pivot open said flaps radially outwardly, and high cam height positioning said cam rollers radially outwardly to pivot closed said flaps radially inwardly.
18. A nozzle according to claim 17 wherein said actuator includes an output rod joined to a proximal end of said bar, and is configured to extend said rod to rotate said bar in said first direction, and to retract said rod to rotate said bar in said second direction.
19. A nozzle according to claim 18 wherein said cams include an up-step at the base of said ramp at said low cam height, and a down-step at the top of said ramp at said high cam height.
20. A nozzle according to claim 19 wherein:
said outer and inner wheels include grooves being complementary with said bar for radially and axially trapping said bar to limit motion thereof to circumferential rotary movement around said duct; and
said cam roller is axially elongate to maintain rolling contact with said control bar as said flaps pivot open and closed in response to rotary movement of said control bar around said duct.