Abstract: A propulsion engine (12) which combusts propellant received from the storage tank (24) in which a portion (28) of the tank contains propellant in the liquid state and in which an ullage (26) in a remaining portion of the tank contains the propellant in a gaseous state including a first propellant circuit (34) coupling liquid propellant stored in the tank to an evaporator (30); a second propellant circuit (36), coupling the gaseous propellant from the evaporator to the propulsion engine combustor and to the ullage; at least one power generating device (14 and 16) disposed in the second propellant circuit between the evaporator and the ullage, for providing a power output from energy of the gaseous propellant flowing in the second propellant circuit controlled by at least one control valve controlling a flow of gaseous propellant to the at least one device under the control of at least one valve control signal; a bypass circuit (40) coupled in parallel with the at least one power generating device containing a

Abstract: A power generating system (10) in accordance with the present invention includes a converter (14) for producing an AC output (16) including a fundamental and at least one harmonic of the fundamental; a frequency analyzer (18), having at least one input coupled to the AC output, for providing an analysis of a frequency spectrum of the AC output; a processor (36), coupled to the frequency analyzer, for calculating at least one switching frequency, each switching frequency being used for transforming a different harmonic within the AC output back to the fundamental; a controller (34), responsive to the at least one calculated switching frequency, for producing control signals at the at least one calculated frequency for transforming the at least one harmonic back to the fundamental; a separating filter (24), coupled to the AC output, for separating the fundamental and that at least one harmonic; at least one converter (30 and 32), coupled to the at least one harmonic from the converter and to the controller, eac

Abstract: An emergency on board power source (28) for jet aircraft having high (22) and low speed (14) spools is disclosed for operation above altitudes where auxiliary power units (14) are operational. A power takeoff (56) is provided from the low speed spool of the jet engine to drive an emergency power unit (28) for supplying electrical and/or hydraulic on board power to the aircraft to maintain control during emergency conditions during which the auxiliary power unit is not operational or is not operational to supply sufficient power to maintain hydraulic or elecrical on board power to uninterruptible electrical and hydraulic power loads.