Patent ID: 7165388

Claim:
A propulsion device utilizing a quantity of working mass, comprising: an outer shell having a first end and a second end; an inner shell having a first end and a second end, the inner shell being disposed within and spaced apart from the outer shell, thereby forming a sealed plenum therebetween, the sealed plenum forming a first turn section at the first end, a heat exchanger section, and a second turn section at the second end, the sealed plenum in the heat exchanger section forming a substantially unobstructed annular duct between the outer shell and the inner shell; a return duct fluidically coupling the plenum adjacent to the first end of the inner shell to the plenum adjacent to the second end of the inner shell; and a working mass driver positioned within the plenum for accelerating a gaseous working mass through the plenum, wherein acceleration of the working mass through the plenum produces a net force acting upon the propulsion device.