Power plants – Reaction motor – With thrust direction modifying means
Reexamination Certificate
2000-01-07
2001-09-18
Freay, Charles G. (Department: 3746)
Power plants
Reaction motor
With thrust direction modifying means
C060S226200
Reexamination Certificate
active
06289670
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a turbojet engine exhaust nozzle mounted on a civilian supersonic aircraft and comprising a thrust reverser.
More specifically, the invention relates to a turbojet engine exhaust nozzle mounted on a supersonic aircraft and comprising an exhaust duct defined within an external cowling, a set of hot flaps mounted in a pivotable manner on the end of said duct, a set of cold flaps mounted in a pivotable manner on a downstream end of the cowling, a thrust reverser comprising two identical eyelids mounted in a pivotable manner downstream of the exhaust duct on either side of an axial plane of symmetry, means for controlling the hot and the cold flaps depending on the flight mode, and means for driving the eyelids from an inactive to an active position or vice-versa.
2. Description of the Related Art
The eyelids of such an exhaust nozzle are each mounted on a stationary structure so as to be pivotable about a transverse axis near the axial plane of symmetry in order to regulate the exhaust cross-section of the engine's exhaust gases as a function of the flight modes. However, this cross-section varies only slightly. On the other hand, noise standards for aircraft in the vicinity of civilian airports require lowering the gas exhaust speeds, especially at takeoff.
These standards require special designs because the engine at takeoff is at full power and the gas flows are substantial.
SUMMARY OF THE INVENTION
The objective of the invention is to provide an exhaust nozzle of the above described kind which reduces noise at takeoff while increasing the gas exhaust cross section.
This goal of the invention is attained by an exhaust nozzle comprising a control mechanism which, in the takeoff mode, moves the two eyelids away from the axial plane of symmetry.
Moreover, the following design steps are taken:
the cold flaps are driven to ensure an obstruction-free, aerodynamic profile with the two eyelids in both the takeoff and the cruise modes;
the cold flaps are linked to the hot flaps by linkrods;
the two eyelids hinge on the ends of two lateral pairs of arms and on the ends of at least one pair of actuators, the arms of each pair of arms and the actuators of each pair of actuators being configured symmetrically relative to the axial plane of symmetry and hinging at their other ends on a stationary structure, and the actuators comprising the control mechanism for the eyelids;
the control mechanism moving the eyelids comprises an actuator connected between the arms of at least one of the pairs of arms;
the two arms of at least one of the pairs of arms are connected by sector gears to assure symmetrical displacement of the eyelids on the arms relative to the axial plane of symmetry;
the actuators comprising the control mechanism for the eyelids may be actuated in an opposing manner in the takeoff mode in order to slightly deflect the gas flow.
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patent: 4641782 (1987-02-01), Woodward
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patent: 5050803 (1991-09-01), Wakeman et al.
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patent: 0761947 A1 (1997-03-01), None
patent: WO 97/48600 (1997-12-01), None
Andre Guyonnet Xavier Jean-Michel
Charier Gilles Alain
Rollin Gilles Louis
Bacon & Thomas PLLC
Freay Charles G.
Rodriguez W.
Snecma Moteurs
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