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George Crompton

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United States


The present invention relates to the propulsion of aircraft by means of a blast of gas delivered at high velocity from what is commonly known in the art as a rocket and the object of the invention is to provide an improved manner and means for utilizing the energy of the gas blast to obtain a maximum propelling effect for an aircraft. While I am aware of the fact that rockets alone have heretofore been employed for propelling an aircraft, with or without planes, all such previous attempts at aircraft propulsion by means of rockets have depended solely upon the reaction of the gases ejected from the rocket for their propulsive effect. The gases ejected from a rocket travel at great velocity and possess tremendous kinetic energy, and consequently at ordinary low altitudes with pure rocket propulsion most of the heat energy of the fuel, or charge, of the rocket is dissipated as kinetic energy of the ejected gases, leaving a comparatively small proportion of the total energy of the charge available for propelling the carrier on which the rocket is mounted at a relatively slow speed, as compared to the speed of the gases themselves. The present invention proposes to utilize to the best possible advantage the energy of the gas blast to obtain a maximum propulsive effect for the aircraft, under varying conditions of operation resulting from propelling the aircraft at different altitudes. Briefly states, the invention contemplates the utilization of the high velocity gases to drive one or more turbine elements which in turn operate propellers for driving the plane in the usual manner when operating at relatively low altitudes where the air is dense. In this conversion of the energy of the gases into mechanical power, the velocity of the ejected gases is reduced to a low value and the energy of the gases is transferred with high efficiency to the much larger mass of air handled by the propellers. The invention also contemplates means whereby when the aircraft rises to higher altitudes in which the air is less dense, the energy of the gas blast can be used partly to drive the propellers and partly to add to their propelling effect by the reaction of the gas blast itself, or in other words by pure rocket action. And then when the air craft rises still higher, where the air would be so thin as to make the propellers useless, the invention provides means whereby the turbine elements can be moved entirely out of the path of the gas blast, whereupon the aircraft is propelled entirely by the rocket effect.

- Robert Goddard


aircraft propulsion, rockets and aircraft propulsion, aircraft fuel


Aerospace Engineering | Aviation | Propulsion and Power







Propulsion of Aircraft