Sunday, June 19, 2011

With No Fish In Afghanistan, Osprey Eats Engines

With No Fish In Afghanistan, Osprey Eats Engines: "The Marine Corps still has some issues to deal with regarding the V-22 Osprey. Although the Corps is big on how well the aircraft is operating in combat, aircraft in-theater are still burning out engines at a startling rate. It took a couple of question cycles on Boeing's pre-Paris media tour in Philadelphia on Monday to get a number out of Navair program manager Col Greg Masiello, but he says that engine time-on-wing in theater is averaging 'between 100 and 200 hours'.

That's a worse number than was cited three years ago, when we reported here that the Navy was threatening to seek a new engine supplier - not a realistic threat but a ploy to get the contractor's attention. At the time, we reported that engines were lasting 300+ hours. (V-22 engines in more benign environments are lasting for 560+ hours, Masiello says. Other helicopter engines aim at four-digit time-on-wing numbers.)

The problem is dust and sand, which gets sucked into the engine and erodes blades and seals. The result is that the Rolls-Royce engines start to lose power and have to be returned to the US for overhaul. It's not a unique issue to the V-22 but it is particularly acute: the tilt-rotor can't use the barrier-type filters on other rotorcraft because they degrade performance in high speed forward flight, and while single-rotor aircraft tend to blow dust away from the helicopter, the V-22's side-by-side rotors throw dust at one another.

blog post photo
This is not good for engines (Marine Corps photo)

A number of measures to reduce the problem are being tried. Every engine returned from overhaul since March 2011 has incorporated 'four specific changes' to increase time-on-wing, Masiello says. Other modifications could be fielded as soon as the end of the year.

A proof-of-concept version of a modified engine air particle suppressor (EAPS) has been fielded for trials, and Maseillo hopes that the engine could be made robust enough to eliminate the EAPS -- which was never designed to tolerate the tornado of crud that the engines encounter in Afghanistan. A further package of modifications is about to be presented to the customer.

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