Accession Number : AD0163976

Title :   Circulation Control Rotor System.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Williams,Robert M.

Report Date : 30 JAN 1973

Pagination or Media Count : 8

Abstract : The patent relates to the rotating blades on a helicopter which are in the shape of a cambered elliptical airfoil with blunt edges. A plurality of slots are employed on the upper surface of the air foil to blow a thin sheet of air tangentially across the surface of the foil and around the trailing edge. Circulation control is achieved by the tangential blowing as the sheet of air adheres to the surface and travels around the trailing edge, detaching beneath the trailing edge at a location determined by the intensity of blowing. The effect of the tangential blowing is relocation of the stagnation stream lines producing increased lift on the foil. The air supplied to the slots is modulated with respect to the azimuth position of the rotor and the speed of the rotating blade so that cyclic control over the lift of the rotor can be accomplished without altering the blade attitude.

Descriptors :   (*ROTOR BLADES(ROTARY WINGS), *PATENTS), (*HELICOPTER ROTORS, PATENTS), FLOW FIELDS, FLOW SEPARATION, LIFT, JET FLAPS, HELICOPTERS

Subject Categories : Aerodynamics
      Helicopters

Distribution Statement : APPROVED FOR PUBLIC RELEASE