This invention relates to an airfoil for an aircraft and more particularly to an airfoil with a design Mach number in the range .7 to 1.0 and having an upper surface designed to delay shock wave induced boundary layer separation until high subsonic Mach numbers well above the critical Mach number are reached. The airfoil has an upper surface shaped to control flow accelerations and pressure distribution over the upper surface and prevents separation of the boundary layer due to shock wave formulation at high subsonic speeds well above the critical Mach number. A highly cambered trailing edge section improves overall airfoil lifting efficiency. WATER PURIFICATION MEMBRANES NASA Case No. ARC-10643 Australia, Canada, France, Address inquiries to: Mail Code: 200-11A [Corresponding to U.S. Patent No. 3,847,652] Reverse osmosis membrane technology has grown dramatically in recent years for the production of fresh water and is particularly important in the purification and reuse of water in space missions. The present invention contemplates the fabrication of membranes of allyl amine as thin films in the presence of a plasma discharge. The membranes are superior in that they do not have to be stored in pure H2O, demonstrate salt rejection rates of 95% or more, do not compress under use, are formed without pinholes, and in any desired configuration, and, possess high adhesion on a variety of substrates. SUPPRESSION OF FLUTTER NASA Case No. LAR-10682-1 Great Britain, Japan, France, Address inquiries to: Mail Code: 313 Langley Station [Corresponding to U. S. Patent No. 3,734,432] An active aerodynamic control system is described for controlling flutter over a large range of oscillatory frequencies unaffected by mass, stiffness, elastic axis, or center of gravity location of the system, mode of vibration, or subsonic Mach number. It consists of one or more pairs of leading edge and trailing edge, hinged or deformable control surfaces, each pair operated in concert by a stability augmentation system. Torsion and bending motions or deflections of the fluttering member are sensed and converted by the stability augmentation system into leading and trailing edge control surface deflections which produce lift forces and pitching moments to suppress flutter. IMPROVEMENTS FOR ABATING EXHAUST NASA Case No. ARC-10712 Australia, Canada, France, Address inquiries to: Mail Code: 200-11A [Corresponding to U.S. Patent No. 3,830,431] A noise abating improvement for jet engines including the provision of apparatus in the primary flow stream of gas turbine engines such as turbojet, turbofan, turboprop, and other jet engines such as ram jets, scram jets and hybrid jet engines, or in either the primary and/or secondary flow streams of turbofan engines or the like, for imparting to the exhaust gases a component rotation or swirl about the engine's longitudinal axis. The rotary component in the exhaust gases has the effect of substantially suppressing the build up on sound energy normally produced by an axial flow exhaust stream. The closed cell, semi-rigid, fiber-loaded self-extinguishing foam of the present invention has properties of retarding penetration of incendiary ballistics, prevention of fire in the void spaces of the aircraft, providing support for the fuel cell, and strengthening the aircraft frame. The foam is based on a polyurethane resin and is filled with fibers and contains a fire retardant material. It does not produce noxious fumes when heated and the strength of the foam is enhanced by the fibers being oriented parallel to the surface of the substrate on which the foam is sprayed. Exclusively licensed to AVCO Corporation. Please direct inquiries to: Fire Protection Materials, AVCO Corporation, AVCO Systems Division, Lowell Industrial Park, Lowell, Massachusetts, 01851, U.S.A. |