Some 60 years after such a design was first conceptualized by Adolf Busemann, it seems like the supersonic biplane is finally creeping its way towards reality.
A supersonic biplane would apparently create less drag than a single-wing aircraft (such as the Concorde) and thus consume less fuel, and most importantly it would create much smaller sonic booms.
Back in the 1950s, Adolf Busemann proposed a biplane design that would avoid sonic booms by, in essence, reflecting the shock wave internally between the two wings. Busemann’s design created too much drag, not enough lift, and would never fly — but now, some 60 years later, research groups at MIT and in Japan working independently of each other have modified Busemann’s design so that it might actually work.
The Japanese approach, developed by engineers at Tohoku University, would have wings that adjust their shape mid-flight to attain supersonic speeds. The American approach increases the gap between the wings, creating more lift.
In a conventional single-wing aircraft, air pressure begins to build at the front and back of the wing as it approaches the speed of sound. As it crosses Mach 1 (761mph), these pockets of air are compressed together and create a sonic boom. As the name suggests, a sonic boom can be as loud as an explosion — and for that reason, planes aren’t allowed to fly at supersonic speeds over land masses.
In both the Japanese and American designs, the supersonic biplane has two triangular wings that both “point” at each other, apparently canceling out the shock wave created by each wing. I say “apparently,” because so far the biplane has only been modeled on a supercomputer. According to the computer model, MIT’s refined biplane would create half the drag of the Concorde, and thus consume significantly less fuel.
The next step is to actually build a supersonic biplane, to see if its sonic boom really is muffled, and its fuel consumption really is as efficient as the computer models suggest. Who knows — if it pans out, we might once again be flying from London to New York in under three hours.