Solving the Efficiency-Speed Paradox

In traditional aviation, going faster always means burning exponentially more fuel because you are fighting atmospheric drag. By using a high-amplitude skip, an aircraft can gain speed by leaving the thickest parts of the atmosphere, effectively "solving" the drag problem that plagues standard supersonic flight.

The removal of turbofan engines from below the wings allows for highly efficient wing designs with very high L/D ratios. To maximize lift and reduce the shockwave effect on the wings, I opted for a tandem design. This setup creates more even lift compared to traditional wings. The tandem wings come in pairs. The upper wing is placed slightly forward of the lower one to ensure positive stability. High-aspect-ratio biplane wings are supported by two vertical supports that double as vertical stabilizers. This reduces the drag induced by a large tail stabilizer while also lowering weight. Having two supports enables the wings to be thinner, which further reduces drag. The leading edges of the wings feature channels to circulate liquid methane. This cools the hottest parts of the wing during supersonic flight. Additionally, the heated methane autogenously pressurizes the methane tank. The nose of the plane also features temperature-controlled methane bleeders to cool the nose and the belly. This is not dead weight, as the methane is consumed to generate boost inside the ducted rocket engine.

Strong, thin tandem wings are well-suited for hypersonic flight and generate high lift even at extreme speeds and altitudes. Active cooling protects critical parts from overheating without adding dead weight. This setup enables fuel-efficient skipping, allowing for low-cost hypersonic flights.

The trajectory of atmospheric skipping is as follows: The plane climbs to its ideal skipping altitude. The thicker, oxygen-rich lower atmosphere reduces fuel consumption through the afterburner effect and air augmentation. Even as oxygen levels drop, the augmented air effect remains. Once the maximum altitude is reached, the main engine is throttled down to a minimum level (possible by turning off unused small engines). As a result, only a "pilot light" level of the engine remains operational. As the thrust level decreases, the plane begins gliding down with almost no fuel consumption. The minimal engine firing still generates some thrust due to pressurized augmented air from supersonic shockwaves. Once the gliding plane reaches oxygen-rich but relatively thin air (roughly 20–25 km), the plane fires its engine at full throttle, harvesting oxygen and augmented air for efficiency. The plane then climbs back to the skipping altitude. Depending on the distance, the plane performs one or more skips. The high lift-to-drag ratio allows it to glide longer distances with minimal fuel consumption. This results in more economical flights than subsonic travel, which wastes a considerable amount of thrust on drag. The ability to glide longer at higher altitudes reduces drag considerably and counterbalances the high fuel consumption of hypersonic flight.