Reduced Pressure Lighter Than Air Machine

A ten percent reduction in pressure at ground level would allow a cubic metre of capacity to lift 130g but generates a frightening pressure differential of 1.5 pounds per square inch.

The lifting element in this machine would be a hollow cube of thin plastic sheet such as the aluminized PET used for snack bags. The actual size of the cube would depend on the manufactured width of the PET rolls. The cube would be supported from the outside by carbon fibre threads attached to a number of anchor points on each face of the cube designed so as to spread the load at the point of attachment. How these cubes would be constructed is a moot point but perhaps a balsa wood frame could be withdrawn through a small resealable hole on completion.

The overall machine would consist of three rigid carbon fibre poles anchored at the centre of each pole in an XYZ configuration. There are eight quadrants nesting in such a configuration e.g. : X+Y+Z+, x-Y+Z+ and so on. Each quadrant would hold one or more cubes in an even number. Tubes would connect the interiors of all cubes together so that they would be at the same pressure. Where a cube is adjacent to another, the cubes would be joined anchor point to anchor point by carbon fibre threads. Where the cube faces out towards the extremity of a carbon fibre pole then that cube would be attached to the pole with carbon fibre threads at intervals out to the extremity of the pole rather like a radio mast. The tensions at all anchor points should equilibrate and the machine would be completely symmetrical in all directions.

Air would be evacuated from the machine and if, (a very big if,) the structure would stand the enormous pressure differential then positive bouyancy would be achieved. There would not be a need to put much further structural stress on the machine as it could rise in height until internal and external pressures were in equilibrium and only then would more evacuation be applied to allow further height rise. Needless to say, the loss of a single cube would be catastrophic and the whole structure would collapse like an overstrung tennis raquet.

Successful construction of such a machine would be a notable first and would generate rather more than the proverbial fifteen minutes of fame. Beyond this there could be significant commercial potential depending on how light the device could be made and hence how high into the atmosphere it could ascend. Forget the lifting of humans and heavy loads and think rather of small electronic payloads such as those used in data transmission and broadcasting. If the device could use solar cells and battery storage to power the means to maintain a reasonably fixed position at a height above 50000 feet then broadcasting to state or country sized audiences might be a cheaper alternative to the use of satellites. It could revolutionize ham radio with the use of simple cross-band repeaters.

If all efforts to get the machine sufficiently light fail then there is a possibilty to flip the balance. Into each cube would be placed a sub container of hydrogen or helium in a partially collapsed bellows or Chinese lantern form filled so as to give some positive bouyancy. As the height increases and pressure decreases this vessel would expand and displace air from that particular cube.

A reasonable start could be made by creating one cube face with anchor points on a test rig and seeing how much reduction in pressure it could withstand and just how many anchor points are needed.