Abstract: A fuel control system for a small gas turbine propulsion engine which enables a long term storage with fuel combined with a rapid start and operation as well as rapid stable control of the fuel flow. The control system includes an electrically controlled servo valve disposed upstream of a fuel pump, with the valve and pressure sensing cavities of a differential pressure control device being maintained full of fuel for a long term storage. Leakproof-type flexure pivots are provided for transmitting motion of an electrical torque motor to the servo valve and transmitting motion of a diaphragm to a throttle located downstream of the fuel pump. A frangible diaphragm is provided at the pump inlet which is adapted to be fractured or otherwise opened to activate the system upon a start-up of the turbine engine and, for this purpose, pressurized gas may be used to temporarily pressurize a fuel tank to burst the frangible diaphragm.

Abstract: In order to control fuel flow at a fuel delivery point for auxiliary power units, and for other low fuel flow applications, an altitude-sensitive fuel flow control device (10) includes a fuel inlet (12) in communication with a fuel source and a fuel outlet (14) in communication with a fuel combustor. The device (10) includes an axially extending rod (16) having a metering surface (22) intermediate the ends (24, 26) thereof which may be located in various positions relative to a fuel flow path (18a, 18b, 18c, 18d, 18e) extending from the fuel inlet (12) to the fuel outlet (14) by axial movement of the rod (16) which varies fuel flow within a preselected range of altitude-dependent fuel flow rates.