Patent GB-456975-A (GB)
Title: Regulating arrangement for the propelling gear of an aircraft having a variable pitch airscrew
IPC: G05D1/06
Filed: 1935-04-18
Abstract: 456,975. Screw propellers. SIEMENS APPARATE UND MASCHINEN GES., 4, Askanischer Platz, Berlin. April 18, 1935, No. 12074. Convention date, April 19, 1934. [Class 114] [See also Group XXIX] Control apparatus for aircraft comprises a regulator 3, Fig. 1, responsive to changes in engine speed, which regulator adjusts the pitch of the propeller blades 1 to maintain the engine speed constant, in combination with a charging pressure regulator 4 maintaining the charging pressure constant, and an automatic steering arrangement, the altimeter or airspeed responsive device of which adjusts the control point or mean regulating valve of the charging pressure regulator. The regulator 4 adjusts a choke or the like preceding the carburetter or blower. The pitch regulator 3 may be in the propeller hub or it may effect adjustment through a shaft passing through the propeller shaft. Both regulators have end stops to prevent the maximum permissible output being exceeded and both are preferably adjusted from a remote point such as the pilot's seat. When used on multi-engined aircraft. Fig. 2, the charging pressure regulator 10 and the propeller pitch regulator 11 of each engine may be connected to common remotely situated adjusting devices 14, 15 so that all the engines have a desired speed and a desired charging pressure. The adjusting device 14 or one or more of the charging pressure regulators where these are not all connected is adjusted by the barometric device or altimeter of an altitude-regulating arrangement so as to maintain a constant flying altitude. The adjusting device 15 common to the propeller pitch regulators is preferably adjusted manually. The adjusting device 14 or one or more of the charging pressure regulators may alternatively be adjusted by the air-speed responsive device of the automatic steering arrangement. The Specification as open to inspection under Sect. 91 describes also practical embodiments of propeller pitch regulator and charging pressure regulator and means for adjusting the control points of one or both regulators manually or according to changes in altitude. The pivoted propeller blades 4, 5, Fig. 1 (Cancelled), have segmental gears 6, 7 meshing with a bevel gear 8 loose on the propeller shaft 3 and driven therefrom through countershaft gearing 14, 13, 10, 9 having a 1 : 1 ratio. The gears 10, 13 are axially fixed in position, the former being splined to a shaft 11 and the latter connected thereto by a quick pitch thread 13a. Variations in the speed of the shaft 3 cause a spring-loaded centrifugal governor 15 to operate the control valve 17 of a servomotor 16 coupled to the shaft 11 so that the relative angular positions of the gear 8 and shaft 3 and hence the pitch of the propeller are varied. The casing of the valve 17 is slidably mounted and may be adjusted by means of a rack 17a and a toothed segment 17if. The latter is operated to adjust the control point by a cable 20 connected to an adjusting device 21. The charging pressure regulator comprises aneroid chamber 26 located in an enlargement of the engine intake pipe 24, the chamber being connected by a rod 28a to the control valve 28 of a servomotor 29 operating a throttle valve 30 in an air conduit leading to a blower or the carburetter. The control point of this regulator is adjusted by a device 34 connected by a cable 33 and a lever 32 to the chamber 26. In the case of a multiengined aircraft, the several cables 20, 33 are connected to drums on the devices 21, 34 respectively. Fig. 6 (Cancelled) shows such a drum 60 operated by a reversible electric motor 59 under the control of a two-way switch 51, 52, 50d. This switch is operated through a lever by an aneroid chamber 50a. The spring- loading on this chamber may be adjusted so as to control the flying altitude by a screwed spindle 64 connected to a flexible shaft 65 geared to an indicating device 77. The contacts 51, 52 of the switch are carried by a segmental worm wheel 53 which is reset by the motor acting through bevel gearing 56 and a worm 54. This subject-matter does not appear in the Specification as accepted.