Special-forces robot whisper-copter enters flight test
DARPA shocks with non-black colour scheme
Flight tests of a revolutionary new robot helicopter have begun, according to the maker, US Aerospace giant Boeing.
Of course, robot helicopters are nothing new. Remotely-piloted types have been possible for decades, and in recent years various craft have emerged which can fly pre-planned routes and even land themselves without human input. Auto landing removes the requirement for a high-bandwidth low-latency comms link over which to pilot the craft.
The Boeing Hummingbird. Curiously, not black.
In the case of the A160T "Hummingbird" programme, however, it's not so much the robot which is the new deal as the helicopter itself. The Hummingbird is intended as a platform for two new kinds of tech which together could make for a more capable whirlybird.
The first of these is "unique optimum speed rotor technology". Existing helicopters tend to maintain a constant rate of rotor revs, in part to control vibration. The Hummingbird uses an, er, revolutionary rotor system which can vary its speed through a much wider range. This should offer a helicopter that "can reach higher altitudes, hover for longer periods of time, go greater distances and operate much more quietly".
There has also been a plan to use heavier fuels in the Hummingbird, as opposed to conventional aviation juice.
"The program also provides a platform for integration and testing of highly efficient heavy fuel engine technologies. These technologies can further advance current range and endurance," according to DARPA, the Defence Advanced Research Projects Agency.
Previous test-bed versions of the Hummingbird have flown, but thus far all have had piston engines. The newer A160T turbine-powered job carried out preliminary hover trials last Friday in California.
"The aircraft used during the tests is the first of 10 A160Ts [Phantom Works] is building for the DARPA and the US Special Operations Command," says Boeing.
Hummingbird choppers will "eventually will fly more than 140 knots with a ceiling of 25,000 to 30,000 ft (high hover capability up to 15,000 ft) for up to 20 hours".
The American special forces are thought to be interested in using the very long-ranging, stealthy helicopters for various missions, including "direct action," "precision resupply" and perhaps the recovery of personnel from deep in enemy territory. The US Navy is another potential customer.
Hummingbird was developed and the DARPA contract won by Frontier Systems of California, which was bought by Boeing in 2005.
Boeing's release is here. ®
no it wouldn't
Transonic is a transition from subsonic to supersonic, but since it's a constant speed, sonic would be accurate.,,
wouldn't that be...
"and an intermediate point is ..sonic.."
One reason high performance 'copter blades have vibration problems is because the tip is supersonic, the hub is subsonic, and an intermediate point is ..sonic..
And a constant speed rotor means that the air speed at any radius is constant.
So how are they controlling the vibration problem and how are they dealing with the airspeed problem?
A new approach to rotor airfoil shape? Subsonic rotation? Adaptive balancing?