Abstract: A high-pressure, moving-piston pulse engine (modified HIPPE) 10 is used to produce one or a series of pulses of acoustic energy in a marine environment for acoustic communication, detection, classification or jamming. The HIPPE engine 10 is modified by removing its nozzle and replacing it with a pipe 58 which is fastened to the exit of the combustion chamber 56. A gas disperser 60 is affixed to the engine 10 or pipe 58 so that a portion of the disperser 60 extends inside of the pipe 58 the inner surface of which is spaced from the outer surface of the disperser 60 so that an annular void is formed between the pipe 58 and the disperser, through which void the combustion gases can be vented. The axial course of the gases is changed by disperser 60 to a controlled course with velocity vectors transverse to the pipe axis. The engine 10 is placed in a body of water 14 at depth or near the surface and operated either manually or automatically.

Abstract: An integrated auxiliary power unit and environmental control unit for an airplane 2, said integrated unit 2 comprising a prime mover 4, a variable geometry compressor 22 operable selectably by bleed air from the propulsion engine of said airplane or connectable via an overrunning clutch 18 to said prime mover, a controlled emission turbine 24 which is shaft-coupled to said compressor 22 and cooperating with said compressor to form an environmental control unit, and means for diverting a portion of the output of said compressor for use as an auxiliary power unit.

Abstract: An environmental control system for a jet aircraft has a single compressor coupled to a cooling turbine and an auxiliary power turbine. The compressor provides air to both turbines. Air to the power turbine is mixed with fuel to form combustion gases to drive the turbine. Air to the cooling turbine is cooled by expansion and used for air conditioning the aircraft cabin. The auxiliary power turbine can be decoupled and the compressor driven by the cooling turbine, which is powered by bleed air from the main engine of the aircraft.