GB598162A - Improvements in or relating to cooling means for aircraft engines - Google Patents

Abstract

598,162. Cooling fans for aero-engines ; variable-pitch propellers. FAIREY AVIATION CO., Ltd., and FORSYTH, A. G. Dec. 10, 1945, No. 33377. Convention date, Feb. 2. [Classes 4 and 114] [Also in Group XXVII] An aircraft engine 10, Fig. 1, is cooled by a fan 18 rotatably mounted on a cylindrical bracket 11 attached to the front face of the engine, the fan 18 and a stator 17. being positioned with their planes rearwardly of the said engine front face. Sleeve 25 is secured to the propeller shaft 19 and carries a gear 34 which meshes with a pinion 46 attached to a spider member 51 which carries in slots 52 the centrifugal clutch weights 54 which when they have reached a predetermined speed, governed by a spring 61, contact and drive the gear 55 which meshes with teeth 63 on the fan hub 62 so driving the fan 18. A variable-pitch mechanism for the propeller 22 consists of two gears 35 and 41, of the same diameter, but having a different number of teeth, driven by gears 33 and 28 on the sleeves 25 and 27 respectively, the sleeve 29 carrying the teeth 30 for actuating the pitch-change worm gear 24. When it is required to change the pitch of the propeller, the gears 35 and 41 are clutched together so giving relative rotation between the sleeves 25 and 29. Four sets of gears are supplied, two having most teeth on the gear 35 and two having most teeth on the gear 41, so that pitch may be altered in either direction. An electric motor 42 is supplied for feathering the propeller. The modification shown in Fig. 6 has a fan drive similar to the abovedescribed embodiment, but the fan in this case is supported by two bearings 74 and 75 mounted on the sleeve 73 secured to the propeller shaft 72. The housing 87 held stationary by the arm 88, also holds the variable-pitch mechanism which consists of two equal diameter gears 85 and 101 with different numbers of teeth connected with a centrifugal clutch spider 92 and clutch outer member 99 and driven by gears on the sleeves 73 and 103 respectively. To alter the pitch, plate 90 is moved to the left, thus allowing the clutch to operate and run the gears 85 and 101 at the same speed to give relative rotation between the sleeves 72 and 103. To cease operating the pitch change, the plate 90 is moved to the right, thus by means of the levers 98 breaking connection between the gears 85 and 101. Specification 597,931 is referred to.