V-22 Osprey a shape-shifter that has come of age

Gestart door jurrien visser (JuVi op Twitter), 11/07/2012 | 08:19 uur

jurrien visser (JuVi op Twitter)

V-22 Osprey a shape-shifter that has come of age

Jul 11, 2012 

Derided as an unsafe ugly duckling during its development, the vertical takeoff V-22 Osprey aircraft has indeed blossomed into a swan. Now widely deployed by the US air force, this high-speed plane is attracting widespread attention, including from the UAE. David Black reports

Helicopters transformed the battlefield, moving troops and equipment directly to where they were needed at 150kph and depositing them vertically on a landing zone. The V-22 Osprey can do all of that - but travelling to its drop-off and pick-up points at a maximum speed of 463kph.

"It can do everything a helicopter can do," says Major Fernando Zapata, an operations officer in the 8th special operations squadron of the US air force. "Except you get there quicker."

Maj Zapata is out on the flight line at Hurlburt Field air force base in the Florida panhandle, home to the USAF's special operations command, which "has a requirement" for 53 of the CV-22 Ospreys.

The tanned, shaven-headed Maj Zapata is a helicopter pilot by trade, but from the evangelical language he uses to describe this unlikely looking aircraft, he is a convert. Obviously there is more to the Osprey than just being faster than a helicopter.

"It's the greatest fun to fly," he says. "Pretty much a dream. You get behind that stick and you know you're not flying a helicopter. You're not flying a fixed-wing [aircraft] either. It's a tilt-rotor, and I guess we're still finding out just exactly what that's going to mean."

The UAE Air Force is also keen to find out what it's going to mean. Since the Osprey's crowd-pleasing appearance at last year's Dubai Airshow, Boeing-Bell has been in discussions to sell the aircraft to the Emirates, India, Japan and Canada.

This week the Osprey is strutting its stuff at the Farnborough International Airshow in England. But it has taken a long time to get here.

The aircraft began life as a result of a US department of defence requirement issued in 1981 for a joint-service vertical take-off and landing experimental aircraft. It first took to the air in 1989, but it was to take two decades, four fatal accidents, a reputation for unreliability and several attempts by politicians to kill it off, before Boeing-Bell managed to turn this ugly duckling into a swan.

Now, despite having US$500 billion (Dh1.83 trillion) chopped out of its budget, the Pentagon is buying 360 MV-22s for the US Marine Corps in addition to its USAF special forces quota, and potentially, a further 50 for the US navy.

Yet seldom has an aircraft encountered so much public hostility. There were problems - leaking hydraulics, engine mounts that had a habit of catching fire and its rotor performance in certain flight configurations made the aircraft unstable. Three training crashes killed a total of 30 Marines.

In 2007, a Time magazine cover story labelled the Osprey "A Flying Shame" and in the past year The New York Times has described the V-22 as "accident-prone" and "unsafe".

But as Richard Whittle points out in The Dream Machine: The Untold History of the Notorious V-22 Osprey, his book on the development of this revolutionary aircraft, the engineers were working at the cutting edge.

The V-22 is a complicated aircraft, engineering-wise. It takes myriad hydraulic and fuel lines to tilt and drive almost 500 kilograms of 6,100-horsepower engine on each wing tip. And it is a shape-shifter, so the wing must take all the stresses as the rotors tilt at full-power and transform the aircraft from turbo-prop transport plane into helicopter.

The fuselage must also be tough enough to resist all the resulting structural stresses. Adding to the challenge, the engineers had to design rotors that folded to save space so the V-22 could operate from ships.

This was a new type of aircraft, with new kinds of challenges. Yes, there were engineering problems - but problems are what engineers fix.

A redesign on the hydraulic feeds to the engine tilt-mountings cured the fire problem. The aerodynamic problem was an old one.

Vortex ring state (VRS) occurs when a rotorcraft descends too quickly and dips its rotors into its own downwash. The result is that rotor blades lose all lift. On the Osprey if one rotor dips into downwash and the other does not, the aircraft flips over.

VRS killed 19 Marines in one accident during the aircraft's development.

Now, Ospreys have audio and visual warnings alerting pilots to VRS, and they are trained to tilt the rotors forward to build speed and escape the effect.

The aircraft has now been in service for five years, flying in some of the most inhospitable conditions imaginable, mostly with the US Marine Corps. So far, there has been only one fatal combat crash: in 2010 in Afghanistan, aUSAF CV-22 missed its landing zone, killing four of the 20 aboard.

"Over 10 years, Ospreys have been the ... safest combat rotorcraft," said Mr Whittle, the author of The Dream Machine.

The rest of the world is starting to listen to the Osprey's "war stories". In 2010, a special forces operation in Kunduz in north-eastern Afghanistan ran into trouble, leaving troops pinned down by enemy fire.

Dust storms prevented helicopters from launching a rescue, but two USAF CV-22s from Kandahar, 643km away on the other side of the 4,572-metre-high Hindu Kush, made it to the landing zone and had 32 US personnel back at base in less than four hours.

And last year, an F-15 pilot who ejected from his aircraft over Libya was rescued by MV-22s flying from an amphibious assault ship 241km away in the Gulf of Sirte. The Marines had the pilot back aboard in just 30 minutes. Sitting in the simulator at Hurlburt Field, Maj Zapata powers up for a flight.

"This controls the tilt rotor angle," he says, indicating a tiny roller on the control stick. "Completely different from a helicopter where you are hauling on the collective to adjust your angle of attack."

A short roll forward, and up we go at an improbable angle and incredible speed.

He spins the roller, the rotors tilt to horizontal and we transition from fast to faster. Pilots who qualify on the Osprey will have flown fixed-wing aircraft and helicopters. Here they learn all the trades they will be expected to master as tilt-rotor jockeys.

V-22s, with their crew of two pilots and one other airman, can fly as many as 24 troops into battle at 262 knots, and evacuate casualties on 12 stretchers. The craft has a cargo hook to lower and retrieve from the hover, and it is much more "tactically agile" than a helicopter, according to the manual.

"That means you can get in and out of Dodge fast," according to crewmen on the flight line.

It can land on runways, or hillsides, in all weathers, including the dust "brown-outs" that frequently defeat helicopters. It can also land on ships of all classes from aircraft carriers to frigates.

It is, however, expensive. The V-22's research and development programme was supposed to cost $39bn, but independent estimates put that at $56bn now, meaning a price tag of about $100 million per aircraft.

It is hoped to get that down to $67m, but Boeing says buyers have to balance the price of the aircraft against its operational flexibility. Say you wanted to fly supplies to a disaster zone: there's the cost of flying a C-130 Hercules to a forward airfield, the cost of transferring the supplies to helicopters and flying them to the scene.

Or you can use an Osprey. One mid-air top-up with fuel, and refuelling at the other end, and the V-22 has a 2,200km range to a disaster area. And did I say it's fast?

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