Autonomous variable density aircraft

Claim 2

An autonomous variable density aircraft comprising: an aircraft body, means defining a variable volume chamber, means carried by the aircraft body for selectively and reversibly varying the amount of ammonia gas within said variable volume chamber to vary the density of said aircraft, a storage tank carried by said aircraft body, a mass of water within said storage tank, said ammonia gas varying means comprising means for controlling the flow of ammonia gas from said variable volume chamber to said storage tank for diffusion within said water to form an aqua-ammonia solution, means for driving ammonia gas from said aqua-ammonia solution and transporting released ammonia gas from said storage tank to said variable volume chamber, said means for feeding ammonia gas from said variable volume chamber to said storage tank comprises a return extending from said variable volume chamber to said storage tank and terminating in a gas diffuser immersed within said solution and said means for driving ammonia gas from said aqua-ammonia solution comprises heater means operatively positioned with respect to said storage tank for heating said aqua-ammonia solution and driving ammonia gas therefrom by increase in temperature of said aqua-ammonia solution.

Claim 3

The aircraft as claimed in claim 1, further comprising a closed loop refrigeration circuit for cooling the aqua-ammonia solution within said tank, said closed loop refrigeration system comprising a closed fluid conduit loop connected to said variable volume chamber for permitting ammonia to flow therethrough, and said loop includes in order: a compressor for compressing ammonia gas received from said variable volume chamber, a condenser downstream of said compressor for condensing said high pressure gaseous ammonia, an evaporator coil positioned within said storage tank and immersed within said aqua-ammonia solution, an expansion valve between said condenser and said evaporator coil for expanding said condensed ammonia to effect heat exchange between said ammonia within said evaporator coil and said aqua-ammonia solution within said tank by the latent heat of vaporization of said liquid ammonia passing through said expansion valve, and a heat exchanger intermediate of said storage tank and said variable volume chamber for cooling gaseous ammonia passing through said closed loop from said evaporator back to said variable volume chamber.

Claim 4

The aircraft as claimed in claim 1, further comprising a check valve within said return extending from said variable volume chamber to said storage tank for preventing flow of gaseous ammonia from said storage tank to said variable volume chamber through said gas compressor and said aircraft further comprises an ammonia gas supply line coupling said storage tank to said variable volume chamber and valve means within said supply line for selectively controlling the flow of ammonia gas given off by said aqua-ammonia solution by temperature increase thereof from said storage tank to said variable volume chamber.

Claim 5

The aircraft as claimed in claim 3, wherein said aircraft body comprises a variable volume articulated vessel comprising a plurality of rectilinear panels hinged joined together along rectilinear edges thereof, at least one flexible sheet within said articulated vessel and sealed along opposed edges to respective, different hinge joined rectilinear rigid panel edges of said vessel to form with said given rigid panels said variable volume chamber and a second variable volume chamber, a mass of hydrocarbon fuel gas carried within said second variable volume chamber and means for feeding fuel gas from said second variable volume chamber to said heater for heating said aqua-ammonia solution within said storage tank.

Claim 6

An autonomous variable density, variable volume articulated aircraft comprising: an aircraft body including a section formed of four relatively rigid rectangular panels hinge joined along respective rectilinear edges and defining a contractible and expandable diamond shaped aircraft body in cross section, non-expandable fluid impervious sheet means having opposed edges sealably joined to respective opposed corners of said diamond shaped body to form with said rigid panels, at least two variable volume chambers, a storage tank fixed to said diamond shaped aircraft body along a hinge joint between two of said rigid panels, a mass of first gas having a density less than air within one of said chambers, a medium for readily absorbing large masses of said first gas within said storage tank to appreciably reduce the volume of said one chamber carrying said gas, the amount of said first gas and said absorbing medium being sufficient to permit a change in density of the aircraft from lighter than air to heavier than air and vice versa, means for transporting said first gas from said one chamber to said tank absorption thereof, means for selectively driving said gas from said absorbing within said tank to said one chamber for increasing the volume of gas within said compartment and the size of said aircraft body and reduction in density of the aircraft, and wherein said medium for absorbing said first gas comprises water, said aircraft further comprising conduit means fluid connecting said one chamber to said storage tank, pump means provided within said conduit means for pumping gas from said one chamber to said storage tank and said conduit means terminating in a gas diffuser within said tank submerged within said water, and wherein said means for driving said gas from said absorbing medium comprises a heater operatively positioned with respect to said tank for heating the solution formed by said water absorbing said first gas to release said gas from said liquid.

Claim 7

An autonomous variable density, variable volume articulated aircraft comprising: an aircraft body including a section formed of four relatively rigid rectangular panels hinge joined along respective rectilinear edges and defining a contractible and expandable diamond shaped aircraft body in cross section, non-expandable fluid impervious sheet means having opposed edges sealably joined to respective opposed corners of said diamond shaped body to form with said rigid panels, at least two variable volume chambers, a storage tank fixed to said diamond shaped aircraft body along a hinge joint between two of said rigid panels, a mass of first gas having a density less than air within one of said chambers, a medium for readily absorbing large masses of said first gas within said storage tank to appreciably reduce the volume of said one chamber carrying said gas, the amount of said first gas and said absorbing medium being sufficient to permit a change in density of the aircraft from lighter than air to heavier than air and vice versa, means for transporting said first gas from said one chamber to said tank absorption thereof, means for selectively driving said gas from said absorbing within said tank to said one chamber for increasing the volume of gas within said compartment and the size of said aircraft body and reduction in density of the aircraft, and wherein said medium for absorbing said first gas comprises water, said aircraft further comprising conduit means fluid connecting said one chamber to said storage tank, pump means provided within said conduit means for pumping gas from said one chamber to said storage tank and said conduit means terminating in a gas diffuser within said tank submerged within said water, and wherein said means for driving said gas from said absorbing medium comprises a heater operatively positioned with respect to said tank for heating the solution formed by said water absorbing said first gas to release said gas from said liquid.

Claim 8

The aircraft as claimed in claim 5, wherein said first gas comprises ammonia and said aircraft further comprises a closed loop refrigeration system including an evaporator coil positioned within said tank carrying said absorbing medium, a conduit connecting said one chamber in a closed loop with said evaporator coil with said first gas acting as the refrigerant working fluid, and said closed loop comprising, in order from said compartment to said evaporator coil, a refrigeration compressor, a condenser, and an expansion valve such that by expnading high pressure liquid ammonia within said evaporator coil temperature of the liquid within said storage tank lowers to increase the gas absorption characteristics of said medium.

Claim 9

The aircraft as claimed in claim 6, further comprising a mass of hydrocarbon fuel gas of a density on the order of that of air within a second chamber and conduit means coupling said second chamber to said heater to allow hydrocarbon fuel gas to be burned to increase the temperature of the liquid within said storage tank for driving off absorbed first gas therefrom.

Claim 10

The aircraft as claimed in claim 7, wherein said sheet means comprise a pair of sheets edge joined together to form three chambers and a fixed mass of lifting gas at a lower density than air is carried within said third chamber for creating in the absence of gas within said first and second chambers a density of the aircraft which is slightly heavier than air, and whereby driving of said first gas from said medium within said storage tank readily changes the density of said aircraft from heavier than air to lighter than air to automatically effect aircraft ascent.

Claim 11

The aircraft as claimed in claim 8, further comprising an internal combustion engine, propulsion means mounted to said aircraft body and conduit means fluid coupling said second chamber carrying said hydrocarbon fuel gas to said engine, whereby the fuel gas within said compartment powers both said heater associated with said liquid medium storage tank and the internal combustion engine propulsion means.