Circulation‐controlled Rotor Aircraft: An account of the basic principles of circulation control by blowing and its possible applications to the stopped rotor aircraft

THE successful development of the gas turbine powerplant made available large quantities of compressed air to the aircraft designer, who realised that the aerodynamics of the aircraft could be significantly modified by its use. This is currently used in naval aircraft where blown flaps have reduced the take‐off and landing speeds. Experimental aircraft have flown with higher lift coefficients on the wings than has been realised using blown flaps. One such aircraft is the B.A.C.‐Hunting 126 jet flap aircraft which uses an internal form of the jet flap. An alternative form of the jet flap has been suggested in America in which the efflux from jet engines mounted in pods below the wing is deflected on to the lower surface of conventional trailing edge flaps which deflect the gas flow and so form an external jet flap.