TINKER AIR FORCE BASE: As part of a new cooperative agreement, air turbines and more than 30 other components from the F-22 Raptor now undergo maintenance here.
In a joint agreement between private manufacturers Lockheed Martin, Honeywell and the Air Force, workers from the 550th Commodities Maintenance Squadron now refurbish the air turbines that provide air from the aircraft’s engines to cool 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.
Under the agreement, Lockheed Martin provides parts and spares to refurbish the turbines while Honeywell provides tools and training. The 550th CMMXS provides the skilled labor.
“It’s kind of a new way of doing business here at Tinker,” said Mark Chenevey, turbine shop supervisor.
Developed in the late 1990s, the turbines are relatively new technology. 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 AFB technicians will likely be seeing more of this type of work in the future.
Tinker AFB 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,” said Tom Gallaway, a turbine tester for the 550th CMMXS.
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,” Rickey Nussbaum, a turbine tester, said.
But, unlike traditional compressor turbines that use metal or ceramic bearings to reduce friction, the air turbines use only air. Since there are 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 revolutions per minute on a cushion of air.
Without surface friction, the new air turbines don’t need lubricating oil. Gloves must be worn to keep skin oil from corroding the parts.
The 550th CMMXS’ 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 AFB mirrored those of newly-manufacturing turbines.
