Researchers at MIT and Stanford say they have advanced the idea of German engineer Adolf Busemann, who in the 1950s proposed that a biplane design could be more efficient and quiet in supersonic flight. Busemann's calculations found that a biplane's two wings could be positioned to cancel out shock waves, but there were problems with the design. Among those, the wings, which joined at their tips, could create egregious amounts of drag when transitioning to supersonic speeds. Now, researchers believe they have resolved the drag problem, found significant increases in efficiency, and significantly reduced sonic boom signatures. There are other challenges to overcome.
The researchers used a computer model to optimize Busemann's biplane configuration and say the outcome not only overcomes the drag problem but would half the drag of conventional supersonic jets like the Concorde when supersonic. Researchers Qiqi Wang, Rui Hu, and Antony Jameson say that by using computer modeling to test 700 different wing configurations at multiple speeds they were able to develop an optimal shape for supersonic biplane configuration. "They found that smoothing out the inner surface of each wing slightly created a wider channel through which air could flow," MIT said in a press release. The result cured the choke point of drag that otherwise could prevent the design from ever reaching optimal speed for significantly reduced drag. Next, production of a 3-D model will allow the researchers to address "other factors affecting flight."