Abstract: A manual positioning system for the metering valve and variable geometry actuator of a fuel control has a pair of drive shafts which have engagement structures mounted respectively on their ends for drivingly engaging the metering valve and the cam of the variable geometry actuator. The drive shafts carry gears which are in meshing engagement with a gear carried by a speed setting lever member. Upon the application of a manual control signal, the engagement structures respectively engage the metering valve and the cam such that the lever member may subsequently position these elements.

Abstract: A fuel control system has a positive displacement gear pump for supplying a metered fuel flow to a gas turbine engine. A variable speed drive mechanism, as constituted by a hysteresis type of electro-magnetic clutch driven by the engine, is operatively connected to the pump for varying the speed of the pump in accordance with a commanded pump speed signal. A scheduling device, which senses various engine parameters, generates a signal indicative of a scheduled fuel flow. The fuel flow signal is, in turn, applied to a function generator which supplies the commanded pump speed signal in accordance with a predetermined relationship between pump speed and fuel flow for the engine sought to be controlled. The relationship between pump speed and fuel flow may be calculated for a wide range of flight conditions since the pressure rise or head across the pump is basically a function of fuel flow. This arrangement obviates the use of a head regulator for highly accurate fuel metering.