The Online Interaction Learning Model: An Integrated Theoretical Framework for Learning Networks

A fuel control system for a gas turbine engine includes a variable metering device from whose downstream side a pair of passages lead respectively to pilot and main engine burners. A throttle valve controls flow to the main burners and is urged open by the pressure downstream of the metering device. A biasing spring urges the throttle valve shut and the bias applied by the spring is variable in accordance with engine speed or during starting of the engine. Variation in spring bias is applied through alteration in the position of a spill valve connected across the metering device.