Air Force Builds Quiet Mach 6 Wind Tunnel

An anonymous reader writes "To help design 'scramjets' -- vehicles that'll travel thousands of miles per hour as they leave the atmosphere and zip around the globe -- the U.S. Air Force has just funded a wind tunnel that operates quietly at Mach 6. To get a quiet flow, the throat of the Mach 6 nozzle must be polished to a near-perfect mirror finish, eliminating roughness that would trip the flow."

Comments

Re:18 inches

[mickyflynn]

they'll use a model, just like the used to before computers. Duh. a model is still "real" unless you take real to mean 1:1 scale with the final production model, or a "real" working aircraft. And they are not going to put all the work and money into building a fullsize or working one without having proven that the basic design is sound. and that can be done with a model.

Some further comments

[Xeirxes]

It said in the article that having these surfaces would greatly reduce the amount of heat that an aircraft recieves when returning to the atmosphere. And I was thinking, does that mean that one small tear could rip the aircraft apart, like the Columbia? It seems like it might be more beneficial to build craft that don't rip up like the space shuttle did, than craft that are even lighter.

Re:I loved the part where...

[ultranova]

At mach 6 at least it would be a *very* fast death.

At Mach 6, yes. But if the thing is turned on when the undergrad is inside, the air doesn't just suddenly jump to Mach 6 - no, it accelerates, and that takes time. It takes an especially long time if the pipe is clogged by a human body.

What will happen is that the undergrad will get an overpressure against her feet or head, likely strong enough to eject her from the pipe. The pressure itself is unlikely to kill her, but injuries sustained when thrown out of the pipe might.