DARPA's New X-Planes Won't Need Runways—Or Pilots

The ideal military cargo aircraft would be able to do three things: Take off from anywhere, carry a huge payload, and fly fast. Of course, getting all three in an airframe means making compromises, and DARPA hopes to find the perfect blend as part of its vertical take-off and landing (VTOL) X-plane program.

This week, the research agency announced that four candidates have been awarded prime contracts for the program. While a VTOL plane is complicated enough on its own, there's an added twist: all four proposals are unmanned designs.

The current standard-bearer for such an aircraft is the Boeing V-22 Osprey, a tilt-rotor craft first developed in the 80s and separately fielded by the Marine Corps and Air Force in the mid-aughts. That long development period was marred by budget overruns, and made the plane a constant target of budget cuts. As Joe Pappalardo wrote in a great report on the program:

The V-22's research and development program was supposed to cost just over $39 billion, but independent estimates predict that it will come to $56 billion—43 percent higher. This price tag—about $100 million per plane, including development costs—becomes a bull's-eye each time politicians look for budget cuts. The 2010 bipartisan deficit commission proposed termination of the Osprey in its list of suggested savings.

The plane has been costly enough, in fact, that the Army has yet to adopt it, and quite possibly won't, despite how useful VTOL capabilities can be.

“I don’t think the Army will end up buying the V-22,” Richard Whittle, author of The Dream Machine: The Untold History of the Notorious V-22 Osprey, told Defense Tech last year. “It’s expensive. It’s complicated. It has disadvantages for their mission. But I think it’s very likely that the Army will buy a tilt-rotor of some kind.”

For its part, DARPA says it wants to completely go back to the drawing board, and develop a VTOL aircraft that's more than a pseudohelicopter.

"We have not made this easy," DARPA program manager Ashish Bagai said last year. "Strapping rockets onto the back of a helicopter is not the type of approach we're looking for. The engineering community is familiar with the numerous attempts in the past that have not worked. This time, rather than tweaking past designs, we are looking for true cross-pollinations of designs and technologies from the fixed-wing and rotary-wing worlds."

Which brings us to the next generation: According to DARPA's goals, the next-gen VTOL plane—which it wants to test as early as 2017—should be smaller and faster than the V-22, which has a cruise speed of 241 knots and can carry 20,000 pounds of cargo. DARPA expects demonstrator aircraft in its program to be able to:

• Achieve a top sustained flight speed of 300 kt-400 kt
• Raise aircraft hover efficiency from 60 percent to at least 75 percent
• Present a more favorable cruise lift-to-drag ratio of at least 10, up from 5-6
• Carry a useful load of at least 40 percent of the vehicle’s projected gross weight of 10,000-12,000 pounds

One easy way to build a smaller plane is to eliminate the cockpit. All four companies awarded a prime contract from DARPA—Aurora Flight Sciences Corporation, The Boeing Company, Karem Aircraft, Inc., and Sikorsky Aircraft Corporation—have gone the unmanned route, which was one option laid out in DARPA's initial guidelines.

The gross weight projection range for those demonstrator aircraft is about a third of the V-22, which suggests the final design resulting from the program will quite likely not be a direct replacement, especially considering the V-22's valued role in special operations.

But as you can see in the renders above, eliminating a cockpit does open up a lot of new design possibilities. And as the military continues to develop its drone ecosystem, it's easy to see the attractiveness of a quick drone that can deliver cargo to and from nearly anywhere.