Boundary layer control system for aircraft

Claim 1

An improved boundary layer control system for aircraft for injecting controlled air, whose temperature and pressure are substantially greater than ambient temperature and pressure and which is obtained from a controllable air source, into a boundary layer region adjacent to an airfoil surface of the aircraft from a plurality of points located spanwise along at least a portion of a surface of a member of the aircraft forward of the airfoil surface, said system comprising: (a) means defining a slot in the forward surface, said slot extending spanwise along the forward surface substantially coextensive with said portion of the forward surface from which controlled air is to be injected; (b) a plurality of longitudinally-extending manifolds for conducting air from the controllable source thereof to points along the forward surface, each said manifold having an open inboard end and an open outboard end; (c) means mounting said plurality of manifolds in successive spanwise arrangement within the aircraft member, said mounting means including a plurality of first supports, each of said first supports securing, in a fixed position, one of said plurality of said manifolds to the aircraft member in proximity to a respective inboard end of said one manifold, and a plurality of second supports, each of said second supports securing one of said plurality of manifolds to the aircraft member in proximity to a respective outboard end of said one manifold so that each said one manifold can expand longitudinally and thus in a spanwise direction along the aircraft member; (d) first means interconnecting said inboard end of the most inboard one of said plurality of manifolds with the controllable air source; (e) a plurality of second means interconnecting the inboard end of each successive outboard one of said plurality of manifolds with the outboard end of an adjacent inboard one of said plurality of manifolds, each said second means being capable of compression upon longitudinal expansion of said manifolds; (f) a plurality of longitudinally-extending nozzle plenums, at least one said nozzle plenum being associated with a corresponding one of said plurality of manifolds, each said nozzle plenum having a closed inboard end and a closed outboard end, and further having a front wall member configured to fit into said slot and having located therealong a plurality of apertures arranged to inject air into the boundary layer region, each said nozzle plenum also having an upper tongue and a lower tongue both extending longitudinally therealong from said inboard end to said outboard end; (g) a plurality of third means interconnecting each nozzle plenum with and supporting each nozzle plenum from a corresponding one of said plurality of manifolds so that said plurality of nozzle plenums are located within the aircraft member and in successive spanwise arrangement therealong, each said third means including first and second feeder ducts respectively located in proximity to said inboard and said outboard ends of each said nozzle plenum, said first and said second feeder ducts being capable of permitting relative longitudinal movement between said nozzle plenum and said corresponding one of said plurality of manifolds, each said third means further including a third feeder duct located intermediate said first and said second feeder ducts; (h) means within the aircraft member defining upper and lower, longitudinal grooves respectively extending above and below and both adjacent to said slot and receiving said upper and lower tongues of said plurality of said nozzle plenums for permitting said nozzle plenums to move longitudinally relative to the aircraft member and for maintaining said front wall member of each said nozzle plenum substantially flush with the forward surface, the outboard end of each said nozzle plenum being adjacent to and separated from the inboard end of an adjacent, outboard one of said nozzle plenums in assembly; and (i) a plurality of sealing means for substantially blocking airflow through said slot between adjacent nozzle plenums, each said sealing means comprising: an upper plate and a lower plate secured to said front wall member at the outboard end of each said nozzle plenum and respectively above and below said apertures therein, said upper and lower plates extending over the inboard end of the front wall member of the adjacent, outboard one of the nozzle plenums and being configured to permit airflow from the plurality of apertures in said adjacent, outboard one of said nozzle plenums upon relative longitudinal movement of said adjacent nozzle plenums; and, flexible means located within said aircraft member and having a longitudinal dimension sufficient to cover the outboard and inboard ends of adjacent nozzle plenums and the separation therebetween, said flexible means being secured to the aircraft member at points in proximity to said outboard and inboard ends of adjacent nozzle plenums.