PROPELLER BLADE Russian patent published in 1998 - IPC

FIELD: aviation; construction of main and steering rotors of rotary-wing aircraft. SUBSTANCE: section of propeller blade has form of aerofoil profile whose chord has length B. Leading edge of profile is rounded-off and trailing edge is blunted. Edges are located at ends of aerofoil-profile chord and are interconnected by means of smooth lines of upper and lower portions of profile contour. leading edge of blade profile has rounding-off radius of upper portion of contour. Radius lies within 0.017xB-0.023xB. Leading edge of blade profile has rounding-off radius of contour. Radius lies within 0.006xB-0.0085xB. Maximum relative thickness of profile lies within 0.105-0.109 and is located at distance X=0.33xB-0.38xB from leading edge of profile along its chord. Ordinates of point of upper and lower portion of contour related to length of profile chord are located at relative distance X/B from leading edge of profile along its chord. EFFECT: increased lifting ability and reduced drag within numbers M=0.2-0.8 and 0.15 <C_y<C_ymax. 4 cl, 6 dwg