Abstract: A novel centrifugal pumping system is disclosed for supplying fuel to aircraft gas turbines. The system has a common rotor with two different sets of impeller blades on opposite sides. A regenerative/liquid-ring starting pump is located on one side of the rotor, and a centrifugal impeller is located on the other. During engine start-up, the regenerative/liquid-ring pump is capable of priming itself and supplies engine fluid and pressure. The starting pump delivers fuel until the main pump reaches a speed sufficient to provide adequate pressure for fuel delivery. At that time, the starting pump is switched off, via a valving system.

Abstract: An "adaptive synchrophaser" is disclosed for modifying the phase angle relationship between aircraft propellers to reduce cabin noise and/or vibration. Rather than use a constant pre-selected angle for a specific passenger cabin configuration during a particular flight mode (e.g., during liftoff or cruise), the synchrophaser periodically monitors actual operating conditions and modifies the phase angle accordingly. In the preferred embodiment, a plurality of transducers (microphones) are installed at several cabin locations to sample noise periodically. The signals are then transmitted via a signal conditioner, a multiplexer and an analog-to-digital converter to a signal processor. The processor calculates the maximum acoustic noise at each microphone location for all possible phase angles. It then identifies the optimum phase angle that resulted in the lowest maximum noise anywhere in the cabin, and signals a synchrophaser to set that angle.