The V-22 Osprey tiltrotor flown by the Marines and Air Force crashes or burns much more often than the military cares to admit. But that hasn’t stopped Osprey-maker Boeing from pitching a new tiltrotor for an ambitious Army program aimed at replacing almost everything the ground combat branch flies … with a single aircraft design.
That’s potentially thousands of new tiltrotors, which take off vertically like helicopters but fly fast like airplanes, thanks to their rotating engine nacelles — but which are also vulnerable to dangerous aerodynamic phenomena and, in the V-22’s case, have been plagued by engine problems.
By continuing to invest in the V-22, the Pentagon is doubling down on a risky bet. If Boeing’s “son of Osprey” gets the greenlight for the comprehensive Joint Multi-Role program, the military will be going all in. But a lot could change between now and 2025, when the first of the new rotorcraft is (loosely) scheduled to enter service. And there’s reason to believe a new tiltrotor could avoid the pitfalls of the Osprey’s design.
Boeing showed off some preliminary artwork of their Joint Multi-Role tiltrotor at an Army confab in Washington, D.C., last week. The art shows a small, sleek scout version and a larger cargo model. “Those images are nothing more than artist concepts and not necessarily associated with a specific design philosophy,” Boeing spokesman Chris Haddox told Danger Room. “The work is just getting underway.”
All the same, the Boeing concept shows apparent improvements over the V-22. Specifically, simpler wings and better rotors.
To fit aboard the Navy assault ships that carry Marines into battle, the V-22 had to have a wing that could fold back along the fuselage — at the cost of extra weight and complexity. The Osprey’s rotors also had to be smaller than ideal for a 25-ton aircraft, forcing the engines to work harder and run hotter.
Over the years, engineers have proposed solutions to this problem. Farhan Gandhi, an engineer at Penn State University, proposed a telescoping rotor blade that would automatically increase in length during a tiltrotor’s helicopter mode, increasing its lifting ability. One retired V-22 engineer told analyst Lee Gaillard that replacing the V-22’s three-blade rotor with a new, five-blade model (.pdf) would boost performance. In the end, Boeing opted for tweaks to the V-22’s software to squeeze every last bit of performance out of the existing design.
Boeing’s conceptual future tiltrotor seems to avoid these half-measures by incorporating bigger rotors from the outset on the scout model, and twin rotors — that is, two sets of blades on each nacelle — for the cargo version. An Army tiltrotor could probably also skip the folding wing mechanism, as seems to be the case in the artist’s renderings. The result could be a safer, better-performing tiltrotor than the troubled V-22. LINK
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