V-22... Times Two
If you like the
twin-engine, twin-rotor Bell-Boeing V-22 Osprey... you'll love what
just came out of the wind tunnel.
Testing has just been wrapped up on the Quad TiltRotor -- a
four-engine tilt-rotor about the size of a Lockheed C-130 Hercules.
The aircraft would take off like a helicopter, lifted by four huge
rotors... two forward and two aft.
"It is a more complex aircraft, but it is what we consider a
very logical extension of the V-22," said Alan Ewing, manager of
advanced concept development for Bell, to the Dallas Morning
A one-fifth scale model has been undergoing tests at the NASA
Langley Research Center Transonic Dynamics Tunnel, as part of the
Army's Joint Heavy Lift project.
If the research conducted at Langley pans out, Bell-Boeing hopes
to build a proof-of-concept demonstrator as early as 2008.
Still to be determined is which manufacturer will provide the
four engines needed to power the aircraft -- engines that need to
provide enough ooomph to keep the Quad TiltRotor in the air, even
if two are inoperable.
One of the biggest issues facing designers on the Osprey was
creating a driveshaft to keep its two rotors in sync, and allow one
engine to power both rotors. That problem -- since resolved on
the Osprey -- is compounded by the additional complexity of the
Besides the Bell-Boeing team, three other teams are also
competing for the Joint Heavy Lift Project. Sikorsky has two
entries in the competition, each with two counter-rotating main
rotors, one placed on top of the other. One also includes
conventional pusher-propellers for forward flight.
Boeing's Phantom Works is also working on an advanced
tandem-rotor helicopter, a modern version of the venerable CH-47
Chinook. Another company, Karem International, is working on what
it calls an "optimum-speed" tilt-rotor.