Abstract: A jet pump having a diffuser, a mixing section and a nozzle produced by electroforming onto at least one highly polished mandrel, whereby the diffuser, mixing section and nozzle have a surface finish of substantially the same quality as the mandrel.

Abstract: An emergency fuel control system for an aircraft engine, which emergency fuel control system comprises means for supplying emergency fuel to the engine such that the fuel supplied to the engine is proportional to engine speed and pressure, first fluidic means which is controlled by a pilot's throttle lever giving a throttle demand and which includes fluidic sensor inputs for limiting engine performance, second fluidic means which has an acceleration control for generating a signal pressure as a particular function of engine compressor ratio, a fluidic mixer for mixing an acceleration control signal and a pilot's control signal such that the pilot cannot demand more fuel than it is safe for the engine to accept, and a fluidic output device which receives signals from the fluidic mixer and which generates a signal which has substantially the same shape as the acceleration control signal but which is at a lower level and which is used to define the minimum amount of fuel that is safely required by the engine in