Liquid Air Powered VTOL

I initially proposed a liquid air powered VTOL aircraft. Due to the high thrust requirements of VTOL, I developed a STOL alternative and wrote an article about it. Lately, I developed a method to lower the thrust requirement for the VTOL aircraft. Validated by computational analysis, I am now proposing this over the STOL design. This is achieved by integrating a pneumatic launch pad with the waste heat recovery system of a cryogenic liquefaction plant.

A VTOL aircraft requires a thrust-to-weight ratio (T/W) greater than 1.0 for vertical displacement. By utilizing a pressurized pneumatic cushion provided by the landing pad, the onboard requirement is reduced to the 0.35 T/W range. The pad ejects warm air at a distance of 0.5 to 1.0 meter beneath the aircraft belly. This creates a high-pressure zone providing necessary lift while increasing the thermal gradient for the liquid air expansion engines, which increases their efficiency.

Efficiency is enhanced by using waste heat from the liquid air production process. The heat of compression is diverted to the pad's pneumatic ejectors. The aircraft maintains higher internal pressure in its ejectors to prevent dust ingestion. Peripheral jets from the pad provide a centering force to guide the craft during descent.

The reduction in takeoff run requirements allows the 150m x 70m STOL footprint to be replaced by a 40m x 40m vertical node. This three-level structure optimizes urban land use. The ground level houses the cryogenic liquefaction plant. The intermediate level functions as the intermodal terminal for Robotic Highway autonomous ground vehicles. The roof level is an open-air VTOL pad with integrated pneumatic ejectors.

By utilizing the tandem bi-plane's high-alpha transition, the aircraft clears the roof vertically and moves into horizontal flight. This setup achieves fuel consumption parity with STOL aircraft while enabling high-frequency operations in dense city blocks.

The combination of ground-assisted VTOL and vertical nodes completes the domestic transportation loop. It removes land-area and energy constraints of vertical flight, resulting in a carbon-neutral, autonomous network powered by localized energy cycles.