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hen one considers the research and development investment, the technological challenges of developing a VSTOL (vertical and short take-off and landing) aircraft, repeated political assaults on the programme, and the bad press suffered in the wake of multiple fatal accidents, it’s remarkable that the Osprey survived a quarter-century long struggle to reach the battlefield. In The Dream Machine: The Untold History of the Notorious V-22 Osprey (Simon & Schuster), veteran military and aviation writer Richard Whittle examines the tortured history of this revolutionary hybrid aircraft and the previously unreported details concerning the deadly test crashes that nearly doomed the programme. What makes the Osprey unique? Richard Whittle (RW): The Osprey is a tiltrotor, meaning it has rotors out on its wingtips that it uses to take off and land – like a helicopter. But once it gets airborne it tilts those rotors forward and flies like an airplane. It’s one solution to what I call the search for aviation’s Holy Grail, which began in the 1930s. The problem with creating that kind of aircraft has always been that you need two different kinds of thrust, vertical and horizontal, which adds extra equipment, extra weight and extra drag. The tiltrotor is an elegant solution because you have only one mechanism to create thrust, and it transforms itself from vertical to horizontal thrust. What advantages does the Osprey have over planes and helicopters? RW: The obvious advantage over airplanes is that it doesn’t need a runway to take-off. The advantage over helicopters is speed. All the
military helicopters in use today fly between 120 and 150 knots (220 and 280km/h). The Osprey can fly faster because once it tilts its rotors forward the rotors, in effect, become propellers. The Osprey cruises at about 250 knots (460km/h). What are the disadvantages as compared to planes and helicopters? RW: The primary disadvantage is that to create rotors that can do the job of a rotor and the job of a propeller, they have to put a special twist in the rotor. That makes the Osprey less efficient than a helicopter at hovering. And to function as a rotor, the Osprey’s prop-rotors, as they’re called, have to be larger than an optimum propeller. So it doesn’t fly as efficiently in airplane mode as an airplane does. What were some of the challenges engineers had to overcome to create the Osprey? RW: There were quite a few. To get the programme started, the Marines had to embed it in a larger programme whose purpose was to create a tiltrotor that all four services could use. The original plan was to build an aircraft that would be able to do 10 different missions. Among other things, it was supposed to be able to cruise at 30,000 feet and fly nap-ofthe-earth (at treetop level). Its cabin was to be pressurised against nuclear, biological and chemical contaminants and it was to incorporate thencutting-edge technologies like fly-bywire flight controls. One major design difficulty was the fact that the Marines wanted a fuselage big enough to carry 24 combat-loaded Marines and a crew of four. At the same time, the aircraft had to fit on an amphibious assault ship. This meant that the Osprey’s rotors had to be smaller than optimum for the size and weight of the fuselage. For years, engineers struggled to find
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