VARIABLE-PITCH PROPELLER AND METHOD OF MEASUREMENT OF ANGULAR POSITION OF ITS BLADES Russian patent published in 1997 - IPC

FIELD: aeronautical engineering; variable-pitch propeller control systems. SUBSTANCE: propeller control device includes hydraulic mechanism for control of blade angle provided with piston 5 fastened with mechanism by means of back coupling; it contains oil supply beta-tube 6 and blade angular position sensor made in form of frequency sensors 7 and 6 with inductors 9 and 10. Device includes also torsion shafts arranged concentrically and used for transmission of torque; torsion shafts are engageable with oil supply tube 6 on side opposite to piston within range of working angles of blades from Φ_rev to Φ_max= Φ_cruise +5-10 deg. Inner torsion shaft is kinematically linked with oil supply tube 6 in axial direction; outer torsion spring 13 is mounted for angular displacement in circumferential direction relative to inner torsion shaft which is ensured by helical pair including pin and helical slot. Torsion shafts are interconnected in circumferential direction via helical spring 21. Torsion shafts carry inductors 9 and 10 engageable with sensors for determination of blade angular position. Method of measurement of angular position of blades consists in generating pulse signals by means of sensors 7 and 8 due to interaction with inductors 9 and 10; inductor 10 is kinematically linked with propeller shaft and inductor 9 is kinematically linked with blades. Pulse signals are directed to counting device for determination of angular position of blades by phase shift of inductors. Rotation of both inductors is effected from oil supply beta-tube 6 whose axial translational motion is used for obtaining phase shift of inductor 9 relative to inductor 10. Axial connection of inductor 9 with blades is broken near feathering angles. EFFECT: enhanced efficiency. 10 cl, 5 dwg