Accession Number : ADD001177

Title :   Quiet Shrouded Circulation Control Propeller.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Williams,Robert M

Report Date : 11 Jul 1974

Pagination or Media Count : 19

Abstract : The patent application describes a propeller capable of generating high thrust at reduced noise levels, weight and drag. The propeller blades employ a tangential slot along the trailing edge of each propeller blade and circulation control blowing from the tangential slot over the trailing edge. Lift is generated by the coanda blowing. The lift is proportional to the momentum flow of the air out of the slot and is substantially independent of the rotational velocity. Additionally a circulation control shroud expands the thrusting slipstream of the propeller so that the shroud diffusion angle is increased and the average exit velocity is reduced, thereby increasing efficiency and reducing noise.

Descriptors :   *Helicopters, *Rotor blades, Patents, Aerodynamic slots, Aspect ratio, Trailing edges, Aerodynamics

Subject Categories : Aerodynamics
      Helicopters

Distribution Statement : APPROVED FOR PUBLIC RELEASE