Abstract: A helicopter tail rotor (14) is provided with a thrust ring. The thrust ring comprises an annular airfoil (16) having a circular opening which is aligned coaxially with the rotor (14). The plane of the airfoil (16) is essentially parallel to the plane of the rotor (14) but slightly offset downstream from the rotor (14). The cross section of the airfoil (16) can have a wide variety of configurations including flat and cambered. The tip vortices (30) produced by the rotor (14) are captured near the downstream surface of the airfoil (16) to produce a circulating airflow (32) that draws air from the upstream region of the airfoil (16) through the opening therein. The aerodynamic action of the airfoil (16) widens the wake diameter of the wash from rotor (14), increases rotor (14) thrust efficiency, reduces the noise level of rotor (14), enhances transverse stability and lowers the vibration level experienced by helicopter (10). The airfoil (16) further serves as a guard to protect the rotor (14).

Abstract: A flexible helicopter rotor includes a vertical rotor axle, a mechanism for rotating the vertical rotor axle in a first rotational direction, and a plurality of segmented flexible airfoils secured to and extending radially from the vertical rotor axle, each segment of each airfoil forming a billowing, canopy-shaped surface as the vertical rotor axle is rotated. Each airfoil includes a cross spar extending radially from the vertical rotor axle and in turn supporting first and second leading edge spars and first and second keel spars. The forward ends of the leading edge spars and keel spars are joined to form an apex of the airfoil at a point ahead of the cross spar. A flexible membrane is secured to the first and second leading edge spars and to the first and second keel spars and is divided thereby to form the segmented flexible airfoil.

Abstract: This invention pertains to helicopter airborne load systems and composite aircraft configurations. The composite aircraft configurations are designed to allow a fixed wing aircraft to take off and land either vertically or in a short ground run when assisted by a rotary winged aircraft such as a helicopter, and includes a maneuverable probe system used to attach two aircraft to form a composite aircraft configuration, the fixed wing aircraft embodying the use of a receptacle or attachment device cooperative with the maneuverable probe to effect the uniting of the aircraft. The helicopter systems airborne includes the use of the probe to cooperate with special external pods capable of carrying loads, fuel and instrumented devices.

Abstract: An aircraft having a wing provided with a semicircular recess in its trailing edge. A powered rotor rotatable about the axis of the recess and having blades whose tips extend close to the semicircular edge below the upper surface of the wing. The rotor produces direct upward thrust on the aircraft and also creates low pressure over the wing and higher pressure below the wing to augment the direct upward thrust of the rotor. Centrifugally moving air impinges on the edge surface of the recess to produce forward thrust. .Iadd.