Return of the Biplane Shigeru Obayashi/Tohoku University

In the 1930s engineer Adolf Busemann conceived of a supersonic biplane that produced no sonic boom—the shock waves would bounce off the plane’s two wings at opposing angles, nullifying each other. But the design created so much drag that the plane wouldn’t have been able to fly. Now two groups are trying to improve the concept with computer simulations. Engineers at Japan’s Tohoku University devised wings with shifting flaps that adjust for drag at different speeds. And researchers from MIT and Stanford University widened the air channel between the wings and tilted their leading and trailing edges. If either design gets built, it could be the first supersonic biplane to take off.

See the supersonic Concorde jet breaking the sound barrier below.

11 Comments

What is the benefit of bi-wing supersonic planes vs single-wing ones, or is this an experiment just to see if it can be mastered?

Didn't you read? It said the two wings create shock waves that bounce off each other nullifying each other therefore no sonic boom.

That would cancel out the shock wave between the 2 wings but that about the shock wave coming off the top of the top wing and the bottom of the bottom wing?

In my opinion its an good experiment.

Zooooooooooooooom, omit boom.

Where's the editor? I created a popsci profile just to make a public comment of how unproffesional this article is not to mention full of false statements that can easily be checked in a physics book (let alone online research papers). I'm thoroughly disappointed.

1) the design never got off the ground because it generates no lift. supersonic craft generate a lifting shock which the biplane does not thus it can't fly.

2) not only does it produce no lifting shock, it has no volume dependant shock so it actaully produces the smallest amount of drag physicaly possible (its drag is purely frictional)

I say that even if we eliminated sonic booms, it wouldn't be all that important. Go up high enough and the boom is distributed over a wide enough area that it simply has no effect. Little too much hype over what seems to be a small contribution.

@capnhowdy, thank you for your comment, but can you please keep it civil? When people are Jack a$$es they usually start a comment war.

TeslasDisciple,

I agree with your comment about the value of eliminating sonic booms. The real problem with supersonic commercial flights is the huge fuel cost increase.

at the risk of opening myself up to criticisms from capnhowdy, shock-shock interaction is a plausible concept to negate sonic effects in the trailing stream of a supersonic craft. It also generates substantial lift due to pressure multipliers which form as each top shock interacts with each bottom shock.

HOWEVER, The picture of the biplane is misleading because in that configuration the pressure up would in fact balance out the pressure down. Having a smaller lower wing than the top would generate the desired shock configuration (high upper wing pressure, low lower wing pressure). Another system would be to use staggered plates instead of the lower wing under a conventional lifting wing body.

And yes, it does generate increased amounts of both Lift and Drag. This I know because I researched using Shockwave interactions to generate lift in wind tunnels while an undergrad at Purdue, and later used FEA (computational analysis) during my master's to test multiple configurations.

Long story short, don't start out your post by being a pompous ass about something when you're wrong. ahem.



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