Helicopter rotor blade
AssigneeAvco Corporation
InventorPeter Crimi
Life of this patent
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Abstract
Torsional oscillations of helicopter rotor blades are reduced with stall, otherwise leading to such torsional oscillations, precluded consistent with allowable high angle of attack, by sucking air from the boundary layer on the upper surface of the blade near the leading edge thereof at a radial location of 80-90% maximum radius thereof and pumping the sucked boundary layer air, utilizing the inherent centrifugal pumping capability of the blade by establishing an exhaust of the centrifugal pumping passage within the blade which allows adequate pumping for the torsional oscillation reduction purpose consistent with the required rate flow of air.
Claims10
Means for reducing torsional oscillations of a blade of a rotary wing aircraft where the flow of air, due to the motion of the aircraft, is essentially in the plane of the rotary wing comprising intake means for sucking air from a boundary layer region located on the upper blade surface and essentially solely at the leading edge within the outer half of the span of the wing and exhaust means for exhausting the air into a region of lower static pressure than the suction region, the air being removed from suction region to exhaust solely by passing centrifugal pumping through wing rotation, said intake means being solely in the 80-90% of maximum wing radius region.
A method of reducing torsional oscillations on helicopter rotor blades comprising the step of sucking air from a boundary layer region located on the upper blade surface and essentially solely at the leading edge within the outer half of the span of the wing and exhausting the air into a region of lower static pressure than the suction region, the air being moved from suction region to exhaust solely by passive centrifugal pumping through wing rotation.
Dependencies are inferred from the claim text.