Back in the 1940's, scientists suggested that a plane with uneven, or oblique, wings might be the best shape for supersonic travel. Sixty years later, no one has been able to make a working, Mach-speed model. Now, the Pentagon's fringe-science arm, Darpa, not only wants to take a whack at the decades-old problem -- the agency is looking for a plane that's one giant, cockeyed wing.

Oblique wings, in theory, provide more lift and less drag than standard aircrafts. But engineers haven't figured out how to build a plane that could handle the "aerodynamic control, aero-structural design, and propulsion integration" that come with the asymmetric approach, Darpa says. There's not even enough "data to date to assess the feasibility" for a supersonic oblique flying wing [OFW] design, the agency notes.

In its new "Switchblade" program, Darpa is aiming to "demonstrate the feasibility and controllability of a supersonic, tailless, variable sweep OFW concept; validate the design methods and control approaches for the design; and facilitate consideration of an OFW planform in the design of potential future operational aircraft."

To start, Darpa wants a good set of OFW plans. They'll have to include:

• Non-expendable aircraft with a wheeled, retractable undercarriage for take-off and landing

• Air breathing propulsion

• Supersonic demonstration at a Mach number greater than or equal to 1.2

• Tailless configuration in supersonic cruise and subsonic loiter conditions

• Variable wing sweep demonstrated in-flight from a minimum wing sweep of not more than 30 degrees to a maximum wing sweep of not less than 60 degrees

• Aspect ratio greater than or equal to 7 at the minimum sweep condition

• Wingspan greater than or equal to 40 feet at the minimum sweep condition.

Darpa isn't exactly sure what an OFW craft would do, if it ever got built. But the agency has some ideas about the kind of tasks a flying wing could handle. Maybe the OFW would spy on targets 2,500 miles away, loitering in the air for 15 hours at a time. Or maybe the plane could become a Mach 2 bomber, dumping 15,000 pounds of ordnance on unsuspecting foes, wondering what the hell that strange thing was, flying overhead.

THERE'S MORE: In the comments, Giovanni links to some of NASA's oblique wing attempts. And Murc points us to Northrop's response to the "Switchblade" chalenge.