TINKER AIR FORCE BASE, Okla., –
Air turbines used in the F-22 Raptor are now being serviced by Tinker's 550th Commodities Maintenance Squadron as part of a new cooperative agreement that will see more than 30 components from the high-tech air superiority fighter undergo maintenance here.
In a joint agreement between private manufacturers Lockheed Martin, Honeywell and the Air Force, workers from the 550th CMMXS are refurbishing the air turbines that provide air from the aircraft's engines for the cooling of avionics and aircrews. An estimated 19 turbines will be repaired for the final quarter for 2009, with the number increasing as the aircraft reaches operational maturity. Work on the new turbines officially began June 30.
"We have 12 people in the shop and all 12 are fully occupied," said Mark Chenevey, turbine shop supervisor. "It's great to have new work coming in like this."
Under the agreement, Lockheed Martin is providing the parts and spares to refurbish the turbines while Honeywell provides the tools and training. The 550th provides the skilled labor.
"It's kind of a new way of doing business here at Tinker," Mr. Chenevey says.
The turbines are relatively new technology, being developed in the late 1990s. They are used in the F-22 and several other aircraft in the Air Force inventory. Many older technology turbines are being replaced with the new turbines, meaning Tinker technicians will likely be seeing more of this type of work in the future.
"This new (turbine) workload will replace the old workload," said Tom Gallaway, turbine tester for the 550th.
Tinker was selected for this work because of its experience in turbine maintenance and testing. The unit repairs and tests turbines not only for the F-22, but for many legacy aircraft systems used by the U.S. and other air forces around the world.
"Most of the stuff we build in this building goes all over the world," says Mr. Gallaway. The new air turbines are unique. The turbines take hot bleed air from an aircraft's engines and, through a combination of compression and expansion, cool the air for use in cooling avionics, aircrew and other equipment.
"It'll be 300 degrees when it comes in and 0 degrees when it comes out," explains turbine tester Rickey Nussbaum.
But, unlike traditional compressor turbines that use metal or ceramic bearings to reduce friction, the air turbines use nothing but air. With no touching metal parts, there is little heat generated and little wear among the moving parts.
"It's new technology," says Ken Kieltyka, program manager. "Where bearings produce friction, this one doesn't. There's no surface friction."
Like a hovercraft, the turbine rotates at up to 90,000 RPMs on a cushion of air.
"It's just air that it rotates on," says Michelle Smith, pneumatic mechanic.
"For us, that's new," says fellow pneumatic mechanic Susan Walters.
The new technology of the turbines meant learning new ways of maintaining them. Honeywell, who developed the air turbines, trained the Tinker team. "I went on TDY to Honeywell, sat with their mechanics and learned everything from teardown to build up," Ms. Smith said. "I like working on them."
Without surface friction, the new air turbines do away with lubricating oil. But gloves must be worn to keep skin oil from corroding the parts.
"It's nice not having to mess with oil," said mechanic Chris Turner.
"But you have to be a little more careful," adds Rex Cox, pneumatic mechanic.
The 550th's testing facilities are relatively new, highly computerized and state-of-the-art. Turbine testers helped develop testing techniques for the new turbines in cooperation with Honeywell. Initial test results of turbines at Tinker mirrored those of newly-manufacturing turbines.
"I think they were amazed that our test numbers were nearly identical to theirs," Mr. Nussbaum said.
"And I think they were impressed with our facility," added Mr. Gallaway.
Honeywell also sought input from the experienced 550th mechanics in developing the Technical Orders used to standardize maintenance. That maintenance won't include traditional overhauls at certain time limits. Instead, explains Mr. Chenevey, the turbines will be inspected and only repaired when a component is broken.
"Not overhaul it, but fix what is broken," Mr. Chenevey said. "That's a new concept for the ALC because we're mainly in the business of overhauling what we get."
Under the agreement, Lockheed will supply the spares for repairs. Not maintaining an inventory of parts and only replacing what is broken is expected to reduce the overall cost of maintenance. "What we don't use goes back to them," Mr. Chenevey said. "That's a cost savings as well."
"It's a great way to do business," said Stephen Hamilton, maintenance scheduler. "They (the 550th) don't have to chase parts and they don't have to worry about not having a part. It's a new way of doing business."
"It's a very different kind of partnership here," agrees Rudolph Chavez, a senior F-22 systems engineer with Lockheed-Martin. "The Raptor now has a presence here at Tinker."