Tiltrotor completes auto tests

May 22, 2014 by Ian Twombly

AgustaWestland announced late last month that its AW609 Tiltrotor has completed dual-engine failure autorotation tests. This is a big milestone in the long development process that will result in the world’s only civilian tiltrotor, planned for certification in 2017.

The aircraft’s massive prop rotors make it impossible to land and take off with the engines in airplane mode. Because the aircraft exists in the space somewhere between an airplane and a helicopter, AW had to work with the FAA to determine exactly how it would be tested. The result was a requirement to be able to land safely in the same way a helicopter does after a failure in either mode. For the testing program that meant a demonstrated ability to go from a worst case scenario of full aircraft mode to a safe landing in full helicopter mode.

The few people outside company test pilots who have flown the aircraft praise its automated systems management capability. That is on display during the autorotation, where the aircraft automatically maintains an angle of incidence that results in 100 percent rpm after an engine or drive system failure. As the aircraft descends it must at some point convert fully to helicopter mode, which the company said it does rapidly. The nacelles go to a full aft position of 95 degrees for a run-on landing.

Most interesting about the aircraft is what might lead to a failure. It’s powered by Pratt & Whitney PT6 engines, each with its own gearbox. Both are connected by a common drive shaft, so if one engine fails the other working engine will provide power to both. AW thinks a complete and simultaneous dual failure is highly improbable, and the only time they envision a subsequent failure is with fuel contamination. Either way, more than 70 tests over 10 flight hours appears to prove the aircraft has the ability to handle such a problem.

AW609 demo flight during HAI's 2014 Heli-Expo

AW609 demo flight during HAI’s 2014 Heli-Expo

3 Responses to “Tiltrotor completes auto tests”

  1. Bill Evans Says:

    Dear Tim, Great article on AW 609 autorotation tests. I do however wonder if the term ‘autogiro’ might be substituted for ‘helicopter’ in the next to last sentence of the third paragraph?
    Best regards, Bill Evans

  2. Dale Long Says:

    Interesting cutting edge info. Thank you.

  3. Alex Kovnat Says:

    Hopefully, this small tiltrotor aircraft will find uses among successful entrepreneurs whose time is valuable, and who need to go places where long-runway airports aren’t close enough.

    In the most recent edition of Flying magazine, we see on the front cover a remarkable fixed wing aircraft, the TBM 900, which can cruise 290 knots — or 330 knots if you don’t mind consuming a little over 64 gallons of jet-A per hour. But while it can takeoff over a 50 foot obstacle within 1385 feet, it needs 2430 feet to land over said obstacle. The Quest Kodiak requires less space, but can’t cruise anywhere near as fast as the TBM 900. Conventional helicopters need no runway at all, but are for the most part no faster than the Kodiak. But tiltrotors like the V-22 and AW609, can cruise at ~300 miles per hour and land in places where even an Aviat Husky might find difficult, as even this great backwoods aircraft has to charge 200 feet or so at the beginning and end of every flight.

    But fuel consumption, initial purchase and operating costs may limit the AW609 to people like flying physicians, successful entertainers and entrepreneurs whose time is valuable enough to require a ~300 mph or so aircraft that can land anywhere a big helicopter can. I look forward to seeing how big a market there is for this remarkable flying machine.

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