GB580488A - Improvements in or relating to variable pitch propeller systems - Google Patents

Abstract

580,488. Automatic control systems. FAIREY AVIATION CO., Ltd. Oct. 12, 1943, No. 16722. Convention date, Nov. 14, 1942. [Class 38 (iv)] [Also in Groups XXIX and XXXIII] Speed.-In a variable-pitch propeller system employing a single propeller, or two coaxial propellers, each propeller blade carries pitchchanging gearing which coact with ring gearing common to all the blades of any one propeller, the ring gearing being driven, to effect normal pitch changing, by a reversible electric motor controlled by an engine-driven governor, a more rapid adjustment being effected at will by the additional use of a clutch-controlled reversible electric booster motor. In the form shown in Fig. 1, two contra-rotating propellers 2, 4 on coaxial shafts 6, 8 have their pitch changed by a reversible electric motor 16, gear-wheels 22, 22<1> coaxial with the shafts 6, 8, and worm-wheels 10, and when required the motor 16 is assisted by a reversible electric booster motor 42 connected to the gear-wheel 22 by a friction clutch 48, 50 under the control of a solenoid 58. The motors 16, 42 may be controlled by the means shown in Fig. 6. This includes a battery 200, a manually operable feathering switch 210, a double switch 212, 212<1> operated by an engine-driven governor 214, which latter can be over-ridden by a manually operable switch 216, a braking switch 218, and cam-controlled limit switches 220, 222, 224, 226, 227 and 228, operating in a manner similar to that described in Specification 564,221. In modifications, (1) the motor 42 is controlled by an electromagnetic clutch, and (2) the motors 16, 42 are disposed on the same side of the gear-wheel 22, the direct drive of which is assisted by the motor 42. Specification 491,041, [Group XXXIII], also is referred to.