Darpa Wants to Rethink the Helicopter to Make It Go Way Faster
BY SPENCER ACKERMAN02.25.132:00 PM
Helicopters are great. They’re maneuverable in very tight spaces, they haul heavy things relative to their small sizes — and, very importantly, they take off and land vertically, removing the need for a big airstrip or aircraft-carrier deck. That function is so important to the military that the U.S. designed fixed-wing aircraft to do the same thing, like the Marines’ iconic Harrier jet or their weird tilt-rotor Osprey.
And they actually all suck, according to the Pentagon’s blue-sky researchers at Darpa, who are launching an effort to blow up and re-imagine helicopters, jump jets and tilt-rotors. It’s time to make these “VTOL” aircraft — the collective term for Vertical Take-Off and Landing — way, way faster, without sacrificing their ability to hover or other functionality.
Like any aircraft, VTOLs are most vulnerable to enemy attack when they’re taking off and landing. But unlike other aircraft, they’re slow to ascend and descend, a particular problem when an adversary lurking nearby knows exactly what pattern the VTOLs will use to get off the ground and back onto it. And when they’re flying, they’re not going nearly as fast as something with, say, a jet engine. It’s a problem the U.S. military has often encountered in warzones. Anyone who’s taken a ride on a Blackhawk or a Chinook in Afghanistan or Iraq has been very thankful for the guy with the .50-caliber gun hanging out the open back of the helo.
Hence Darpa’s newest aircraft program. It’s called the VTOL X-Plane and officially launches Monday. The idea is to rethink the designs of anything that takes off and lands vertically, to make it faster; hover and cruise more efficiently; and haul more stuff. By the time it’s done in 52 months, it just might result in an aircraft that doesn’t look at all like a helicopter, jump jet or tilt-rotor.
“What we’re interested in doing is flying much faster than we have been able to do with helicopters,” program manager Ashish Bagai told reporters on a conference call. Helos and other VTOL aircraft typically max out at 170 knots. Bagai wants the X-Plane to do 300. “We want to fly at improved efficiencies, both in hover and at forward flight,” he said, “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.”
It’s also not springing up from specific improvements in helicopter or other VTOL capability in the aerospace industry. Nor does it arise from any tech innovations Darpa sees on the horizon. “We have seen in the community a few isolated and novel approaches to addressing this problem but we’re in danger of suffering an attrition in our technology bases,” Bagai said. “This is an opportunity Darpa would like to put forth to advance the state of the art, well beyond where we are today.”
Good luck with that. Helicopters usually get faster by adding power and messing with the rotor placements. (See, for instance, Sikorsky’s funky ’70s-era designs.) But that typically compromises their ability to hover. Nor, Bagai conceded, have fixed-wing VTOLs cracked the speed/hover/power problem. And the V-22 Osprey tilt-rotor has endured more than its fair share of challenges.
All of which raises questions about the VTOL X-Plane’s ability to actually deliver on its promises. Bagai thinks there’s an opportunity for “hybridization” by mashing up the fixed-wing and helicopter design communities, but like many Darpa projects, the program will pulse those communities rather than take advantage of improvements on the cusp of maturity.
Darpa’s setting a “very aggressive” development schedule, Bagai said, that’s targeting a flight test in 42 months. Ten months later, when the program ends, “we want to have demonstrated all our key objectives and have a flying aircraft available,” he said. If it fails, helicopters, jump jets and tilt-rotors won’t be any worse off. If it succeeds, the VTOL X-Plane pretty much represents their next generation.
