MAIN ROTOR Russian patent published in 1995 - IPC

FIELD: aviation. SUBSTANCE: main rotor has hub 1, blades which consist of inner part 3 and outer part 2; outer part 2 has aerofoil profile in its section and inner part 3 is oval in section. Outer part 2 is fitted on inner part for longitudinal motion over it; to this end, guides or rails and sleds are provided between both parts on the spar. Motion of inner part 3 is effected by means of mechanism with gears 9 and 10 on hollow shaft 11 with nut 12 at the end; motion screw 13 is passed through the shaft which also carries gear 16 thrown into engagement with gear racks 17 and 18. EFFECT: enhanced efficiency of main rotor through increased range of change of its diameter and reduced relative thickness of aerofoil section. 2 cl, 6 dwg