PROPELLER BLADE AND ITS SHANK Russian patent published in 1999 - IPC

FIELD: aeronautical engineering; manufacture of propeller blades from composite materials. SUBSTANCE: propeller blade includes fin and shank. Blade is made from composite material. Blade consists of envelope and spar. Envelope is made in form of closed loop from layers of unidirectional high- modulus fibers. Aspect ratio of envelope is equal to λ = 2,9 ... 5,5. Fin sweep angle is equal to x=35 to 42 deg over leading edge at standard radius F= 0.7. Envelope of shank is provided with filler made from composite material. Envelope of shank has thread with 4 to 5 turns. Their pitch ranges from 0.16 to 0.29 of diameter of shank; angle of bottom of thread ranges from 90 to 120 deg. Rounding-off radius of points and bottom of thread ranges from 0.11 to 0.14 of pitch. Outer surface of shank envelope includes layer of high-strength rubber over are of thread. EFFECT: increased strength life; enhanced reliability of propeller blade made from composite material. 3 cl, 4 dwg