Abstract: A control circuit adapted to receive at least first, second and third input signals. The first input signal is a signal representative of the fuel pressure at the output of a pump. The second signal is a signal representative of the fuel pressure in the manifold of fuel disbursement means which is supplied through a controllable valve, by the fuel pump. The third signal is a signal representative of the pressure at the inlet to the pump. The control circuit further includes a feedback path for continuously circulating fuel from the manifold to the pump inlet. In one arrangement of the fuel supply system, there is an aperture in parallel with the controllable valve and an aperture in the feedback path.

Abstract: An apparatus and method are disclosed which ensures that a rotor-shaft assembly is in rotational balance after assembly of the individually balanced components by preventing the creation of any imbalance during assembly. The rotor member is formed with an annular groove about the nose portion at a point near its mounting face, which during assembly is crimped before any shaft bending occurs, thereby eliminating any rotor-shaft imbalance.

Abstract: The use of a single main centrifugal fuel pump for supplying fuel to an aircraft gas turbine engine has advantages over other known systems, however a problem has existed in that the centrifugal pump, when driven in a fixed ratio to the engine speed, cannot deliver fuel at adequate pressure under engine starting conditions. The disclosed fuel supply system using a main centrifugal pump overcomes this shortcoming by having a turbine-driven start pump added to the fuel supply with both the turbine and the start pump receiving fuel pumped by the main centrifugal pump and the turbine utiliziing the high flow, low pressure fuel to drive the start pump which incresases the pressure of the fuel to a value adequate for engine starting. The start pump delivers fuel until such time as the main centrifugal fuel pump has reached a speed to provide the fuel to the engine at the required pressure, at which time the turbine is no longer driven and the output of the start pump goes to zero.