DEVICE FOR ADDITIONAL COMPENSATION OF REACTIVE TORQUE OF MAIN ROTOR OF SINGLE-ROTOR HELICOPTER Russian patent published in 2006 - IPC B64C27/82 B64C5/02 

FIELD: structural members helicopter; devices for compensation of reactive torque of main rotor.

SUBSTANCE: proposed device has two longitudinal fences; one of them is mounted on external side of board of tail boom on side of retreating blade and is located above second longitudinal fence mounted on external side of board of tail boom on side of advancing blade; longitudinal fence located on side of retreating blade is mounted in lower quarter part of tail boom cross-section at angle 90-140° from upper point of tail boom cross section; height of this fence is no less than 10% of maximum width of tail boom cross section and longitudinal fence located on side of advancing blade is mounted in lower quarter of tail boom cross section at angle of 0-50° from lower point of tail boom cross section. Position of upper fence on side of retreating blade together with proposed height of this fence imparts additionally functions of deflector which considerable changes direction of vertical layer of inductive flow of main rotor above trail boom from practically vertical to direction dictated by plane of position of structural depth of fence. Super-circulation flow around boom thus formed gives rise to additional force directed towards part of main rotor disk with advancing blade. Second fence ensures drawing down point of boundary layer separation and simultaneously separates increased pressure zone arising under action of first fence from negative pressure zone, thus ensuring rise of pressure on tail boom surface on side of retreating blade and increasing on first boom arising under action of first fence.

EFFECT: increased lateral force on tail boom and creating of compensation part of reactive torque at hovering and low speeds.

7 dwg