Integrated Aero-Thermodynamic Propulsion

I had previously proposed a Short Takeoff and Landing (STOL) propeller plane with boxer engines embedded inside the wing without a nacelle. This time, I am improving on the idea by replacing the propeller and instead installing a turbine-powered, direct-drive radial fan to push the air coming from the leading edge of the wing to its trailing edge. This functions as an expanded version of a rocket turbopump. The width of the wing allows for a larger diameter fan and turbine, which significantly improves their performance.

Some of the air compressed by the radial fan is used by the turbine assembly below the fan. This increases the combustion efficiency of the turbine without needing a separate turbo-compressor unit. The exhaust of the turbine is then entrained by the compressed air of the radial fan, which increases the net thrust efficiency of the propulsion system. Ejecting this stream of air from the trailing edge of the wing results in a virtual wing effect, which increases the lift-to-drag ratio. With a classical aviation propulsion system, you cannot achieve that. This setup lowers the stall speed, which shortens the required runway length for the plane. The ejected air can be directed with internal flaps to point downward, allowing the plane to land on ultra-short runways at full throttle levels. More importantly, this fluidic control system allows for higher control authority during landing, which is missing on most aircraft due to low throttle and thrust levels during approach.

The trailing exhaust can be extended to cover more of the wing span. This allows for fluidic flight controls for the plane with zero parasitic drag. By controlling the ejected air from different sections of the wing, the plane can maneuver way more fluently compared to physical control surfaces such as conventional ailerons.

Additionally, this clean setup allows for my signature staggered biplane design. Once I free the wing from the burden of an external nacelle, I can add the second wing to further improve the lift-to-drag ratio. This setup allows for dual propulsion, with one embedded engine inside the upper wing and the other at the lower wing root. The boxed-wing structure makes the entire wing assembly stronger, lowering its structural weight. The vertical supports between the wings double as vertical stabilizers, and the whole tail assembly of the plane is removed to completely eliminate the drag and weight penalty of the tail. The more distant location of these vertical supports at the tips compared to a traditional tail allows for much higher control authority.

I also plan to design the belly of the plane to be flat. This increases the lift surface of the plane considerably. This compounded lift-to-drag efficiency—combining the flat belly, biplane wings, virtual wing, and reduced drag due to the removal of the tail—allows the plane to fly at a significantly higher altitude compared to traditional commercial planes. Higher altitudes mean reduced atmospheric air density, which reduces drag and allows for even higher airspeeds. This ultimately reduces flight time and improves fuel economy.