Thrust reverser position determination system and method

#The present invention relates to jet engine thrust reversers and, more particularly, to a thrust reverser actuation system with the ability to determine the position of system components from the rotational position of a motor within the system.

#When a jet-powered aircraft lands, the landing gear brakes and imposed aerodynamic drag loads (e.g., flaps, spoilers, etc.) of the aircraft may not be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the braking of the aircraft. When deployed a thrust reverser redirects the rearward thrust of the jet engine to a forward or semi-forward direction to decelerate the aircraft upon landing. When in the stowed position, the thrust reverser is in a position that generally does not redirect the engine thrust.

#Various thrust reverser designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Thrust reverser designs used most prominently with turbofan jet engines fall into three general categories: (1) cascade-type thrust reversers; (2) target-type thrust reversers; and (3) pivot door thrust reversers. Each of these designs employs a different type of moveable thrust reverser component to change the direction of the jet thrust.

#FIG. 1 is a perspective view of an aircraft engine;

#FIG. 2 is a perspective view of portions of an engine fan cowl and thrust reverser system utilized with the engine of FIG. 1;

#FIG. 3 is a partial cross section view taken along line 3—3 of FIG. 2;

#Before proceeding with the detailed description of the invention, it is to be appreciated that the present invention is not limited to use in conjunction with a specific thrust reverser system design. Although the present invention is explicitly described as being implemented in a cascade-type thrust reverser system, in which transcowls are used as the moveable thrust reverser component, it will be appreciated that it can be implemented in other thrust reverser system designs.

#Turning now to the description, and with reference first to FIG. 1, a perspective view of portions of an aircraft jet engine fan case 10 that incorporates a cascade-type thrust reverser is depicted. The jet engine fan case 10 includes a pair of semi-circular transcowls 12 that are positioned circumferentially on the outside of the jet engine fan case 10.

#As shown more particularly in FIGS. 2 and 3, the transcowls 12 cover a plurality of cascade vanes 14, which are positioned between the transcowls 12 and a bypass air flow path 16. When in the stowed position, as depicted in FIG. 3, the transcowls 12 are pressed against one or more stow seals 15, which keep air in the bypass air flow path 16 when the thrust reversers are in the stowed position. A series of blocker doors 18 are mechanically linked to the transcowls 12 via a drag link 22 that is rotatably connected to an inner wall 24 that surrounds the engine core 26. In the stowed position, the blocker doors 18 form a portion of an outer wall 25 and are therefore oriented parallel to the bypass air flow path 16. When the thrust reversers are commanded to deploy, the transcowls 12 are translated aft, causing the blocker doors 18 to rotate into a deployed position, such that the bypass air flow path 16 is blocked. This also causes the cascade vanes 14 to be exposed and the bypass air flow to be redirected out the cascade vanes 14. The redirection of the bypass air flow in a forward direction creates a reverse thrust and, thus, works to slow the airplane.