Supersonic Bi-Directional Flying Wing is a novel concept suggested by Prof. Gecheng Zha at University of Miami for supersonic airplane to achieve zero or very low sonic boom, low supersonic wave drag, and high subsonic performance. The SBiDir-FW planform is symmetric about both longitudinal and span axes. For supersonic flight, the planform will have low aspect ratio and high sweep angle to minimize wave drag and remove sonic boom. For subsonic mode, the airplane will rotate 90deg in flight and the sweep angle will be reduced and aspect ratio will be increased substantially. In simple words, we like the airplane to be slender for supersonic high speed flight. For low speed such as take-off/landing, we like the airplane to have wide wing span with high aspect ratio. Conventional supersonic airplane compromises for low and high speed and ends up being unable to optimize either. The SbiDir-FW is promising to remove the conflict. The same concept can also apply to hypersonic one-stage to orbit vehicles.
The preliminary CFD simulation shows that it obtains smooth ground sonic overpressure of 0.3psf with L/Dp = 16 at Mach 2.0. The ground pressure signature is not the N shape wave with two impulsive shock waves, but is in a smooth sine shape wave, which means no sonic boom. SBiDir-FW is at its infant stage and long term research and development are needed to maturate the technology. Imagine to fly from New York to Los Angeles in 2 hours instead of 6 hours, New York to Tokyo in 4 hours instead of 15 hours.
On Aug. 14, 2012, Time magazine reported this supersonic concept research grant awarded from NASA as one of the 10 "most fantastic projects that NASA hopes will be inspiring people long after Curiosity has finished exploring Mars". Please see the Time link. http://techland.time.com/2012/08/13/whats-next-for-nasa-10-wild-newly-funded-projects/slide/silent-and-efficient-supersonic-bi-directional-flying-wing/#silent-and-efficient-supersonic-bi-directional-flying-wing
For more information, please visit Prof. Zha's lab webpage at www.miami.edu/acfdlab.
