GB1311841A - Control system - Google Patents

Abstract

1311841 Automatic speed control DEFENCE SECRETARY OF STATE FOR 20 March 1968 [23 Dec 1968 31 Dec 1968] 55679/68 and 61807/68 Heading G3R [Also in Division F1] In a gas turbine engine control system a manual control element 25 is connected to a fuel throttle actuator 5 by either a mechanical or an electrical connection, there being a means for selecting one or the other connection. The mechanical connection comprises linkage 141 with a selector latch 142 and the electrical connection comprises circuitry through the gauged switches 20, 21, 22, 23 and 120, the selection being through the switches. When the mechanical connection is selected the lever 25 is positionable in terms of engine speed and may also be adapted to control a group of engines. Provision for individual engine control may be made and subsidiary levers 6 for fine engine control may be provided. The electrical connection may comprise a motor driving differential gearing of the throttle valves. Engine speed may also be controlled by a computer 92 whereby the lever is movable to select sub-modes in which the computer determines fuel flow at different engine ratings, each rating being selectable by the lever 25 and keeping the engines at a given speed, temperature or pressure rating. When operating in this manner, the element may not necessarily indicate the engine speed and in order to allow for immediate selection of the mechanical connection, a motor is provided to drive the lever to the correct setting of engine speed on selection of this connection. Other sub-modes depending either on an aircraft or an engine parameter may be selected. One mode may be automatic determination of power requirements for particular operations e.g. takeoff, cruise or landing, selected by the lever. In these cases the computer controls fuel flow in response to different parameters fed in by the crew or picked up from sensors on the aircraft. Other modes may be forward or vertical air speed.