The Defense Advanced Research Projects Agency (DARPA) announced on Monday Feb. 25 that it is working to develop a new aircraft that will operate like a helicopter but fly as fast as an airplane.

The agency has titled the program the VTOL X-Plane and plans to finish the project in 52 months. VTOL (Vertical Take-Off and Landing) aircraft usually only get up to about 170 knots but those working on the X-Plane want it to get up to 300.

"What we're interested in doing is flying much faster than we have been able to do with helicopters," says program manager Ashish Bagai. "We want to fly at improved efficiencies, both in hover and at forward flight and we want to demonstrate this is possible without sacrificing the ability to do useful work. And to do this concurrently is a very big challenge."

Helicopters are uniquely valuable in terms of maneuverability, storage and the ability to take off and land vertically, which negates any need for airstrips. They are, however, slower than many other aircraft, particularly when moving upward or downward. This makes them more vulnerable to attack from other military aircraft.

DARPA's proposed invention would appear to be a ground-breaking innovation, merging the helicopter and plane into a new hybrid aircraft. The problem, however, is that speed in helicopters is usually boosted through increased power and adjustments to the rotors: both of which usually detract from hovering capabilities. This means that DARPA will have to make some major technological leaps if it wants to successfully implement its new aircraft.

That said, DARPA is aggressively following the project. A test flight for the X-Plane is scheduled 42 months from now. By the end of development, Bagai says, "we want to have demonstrated all our key objectives and have a flying aircraft available."

The X-Plane may not be a surprising disappointment if it fails. But can you imagine what it would be like if it doesn't?