Ever since a hot air balloon nearly crashed into my roof I’ve been intrigued by these vehicles. Their combination of high drag and low manoeuvrability make them pretty unexciting transportation devices though.
Today’s invention aims to change that.
The net upthrust on the balloon envelope is mostly due to the product of its plan area and the difference in atmospheric pressure between top and bottom surfaces. This makes it possible to play with the geometry without sacrificing buoyancy.
Imagine a balloon envelope say, two meters in height, 100m wide and 4m broad. This could be formed with a respectable aerofoil section and thus of generating additional lift. For extra safety, two half-size wings could be joined into a biplane. A 4m wide wing section filled with hot air (from one end) would be capable of some flexure (via cables) and thus much more directional control.
Equip the whole thing with a small fan to provide some motive power and you have a robust, steerable flying machine that can pack into the boot of a biggish car.