Patent Application
20080258016
The present invention relates to aircraft engine nacelles, and more particularly to aircraft engine nacelles having thrust reverser cowl doors and core cowl doors which are independently hinged to eliminate a lower bi-fi splitter.
Gas turbine engines are mounted on an aircraft by a support structure such as a pylon. A nacelle arrangement encloses the engine forming a shelter which is aerodynamically contoured to reduce drag. The nacelle arrangement is supported in part from the pylon and in part from the engine.
Conventional nacelle arrangements include a removable metal and or composite cowling. The cowling includes a fan duct reverser cowl and a core cowl. The larger diameter fan duct reverser cowl and the smaller diameter core cowl are interconnected by a bi-fi wall. Although the bi-fi provides additional stiffness for the nacelle, the bi-fi splitter may partially block the bypass fan stream and reduce engine efficiency.
Accordingly, it is desirable to provide an engine nacelle arrangement which minimizes engine bypass fan steam flow.
The nacelle assembly according to the present invention includes separately movable fan cowl doors, thrust reverser doors, and core cowl doors. The thrust reverser doors and core cowl doors have separate thrust reverser door hinge lines and core cowl door hinge lines for independent operation to eliminate the requirement of a lower bi-fi splitter. The removal of the lower Bi-Fi splitter provides improved aerodynamic packaging with improved performance by reducing drag in the bypass fan stream.
The present invention therefore provides an engine nacelle arrangement which minimizes engine bypass fan steam flow.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently disclosed embodiment. The drawings that accompany the detailed description can be briefly described as follows:
The nacelle assembly 20 includes separately movable fan cowl doors 22L, 22R, thrust reverser doors 24L, 24R, and core cowl doors 26L, 26R. The core cowl doors 26L, 26R are located at least partially radially within the thrust reverser doors 24L, 24R. Each of the fan cowl doors 22L, 22R, thrust reverser doors 24L, 24R, and core cowl doors 26L, 26R are defined to hinge about a respective hinge line 28L, 28R, 30L, 30R, and 32L, 32R. It should be understood that the fan cowl door 22, the thrust reverser door 24, and the core cowl door 26 include both left hand (LH) and right hand (RH) clam shell-type doors which each include a respective hinge. It should be understood that various locking mechanism may be utilized with each of the separately movable fan cowl doors 22L, 22R, thrust reverser doors 24L, 24R, and core cowl doors 26L, 26R which need not be described in detail herein.
The clam shell-type fan cowl doors 22L, 22R, thrust reverser doors 24L, 24R, and core cowl doors 26L, 26R open around their respective hinge lines 28L, 28R, 30L, 30R, and 32L, 32R. The core cowl doors hinge lines 32L, 32R are separate from the thrust reverser door hinge lines 30L, 30R (
As the thrust reverser doors 24L, 24R and the core cowl doors 26L, 26R, separate the thrust reverser door hinge lines 30L, 30R from the core cowl doors hinge lines 32L, 32R the independent operation eliminates the requirement for a lower bi-fi splitter. The removal of the lower bi-fi splitter provides improved aerodynamic packaging with improved performance by reducing drag in the bypass fan stream. Service lines and the like which were routed through the lower bi-fi splitter are now routed through the upper bi-fi splitter 34. Although conventional blocker door thrust reverser systems may not be utilized with this door opening system, other thrust reverser systems such as pivot door systems may be utilized herewith.
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
It should be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit from the instant invention.
The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The disclosed embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
