PROPELLER BLADE Russian patent published in 1997 - IPC

FIELD: aeronautical engineering; construction of blades of steering rotors and propellers, as well as construction of fans including fans of wind tunnels and aircraft engines. SUBSTANCE: blade has envelope made in form of closed contour from layers of unidirectional high-modulus fibres laid at angle of ±45^° deg relative to longitudinal axis of blade and solid spar located inside contour which is made from high-strength organic plastic fibres at ultimate strength of σ_b≥180 kg/sq.mm laid along its longitudinal axis. Geometric elongation of blade is equal to , contraction is equal to and thickness of envelope wall is equal to where Cⁱ is maximum thickness of contour profile in i-M section. Area of spar in intervals of distances between near-shank part of blade and section at radius r = 0,7±5% exceeds magnitude of length of contour l_icon by 0.8 to 2.2 times in each section from this section to tip of blade. Spar is deflected together with edge at point of its meeting with leading edge if fin by magnitude of present angle. EFFECT: increased strength life of propeller and enhanced reliability. 2 cl, 3 dwg