The U.S. Air Force (USAF) in now operating the first of a planned fleet of 1,440 CFM56-2 engines (military designation F108) upgraded as part of the CFM Performance Upgrade Program (C-PUP). The engines power the USAF fleet of KC-135R Stratotanker aircraft and the program is expected to be completed over the next 12 years.
In addition, the U.S. Navy has also ordered upgrades for 75 engines in its E-6B Mercury aircraft fleet.
“The improved fuel efficiency and lower maintenance costs these upgrades will bring can save the USAF as much as $2 billion U.S. over the life of the program,” said Jeff Bauer, CFM56-2 Military Program manager. ”This program is a great example of how an operator and a supplier can work together to find a great solution.
“CFM was originally approached by the Navy nearly four years ago; they wanted to find a way to improve their engine time on wing while the USAF was looking for improved fuel efficiency. The solution was to use new fuel-efficient technologies from today’s commercial engines to upgrade the older military engines.”
The C-PUP configuration incorporates new high-pressure compressor airfoils designed using three-dimensional aerodynamic techniques to improve engine efficiency. As a result, the upgrade will provide a 1.5 percent improvement in engine specific fuel consumption, which equates to as much as 3.8 million gallons of fleet fuel burn reduction by the end of the fifth year at projected upgrade rates.
In addition, new high-pressure turbine hardware that incorporates the latest materials technology will extend engine life by improving the EGT (exhaust gas temperature) margin by 15 degrees Celsius. Every degree of EGT margin equates to 1,000 more hours on wing.
This technology is used today in CFM’s highly successful commercial engines powering the Airbus A320 and Boeing Next-Generation 737 families. CFM had a similar upgrade program with the CFM56-3 commercial engine that powers the Boeing 737 Classic.
The initial 15 engine upgrades are being performed by CFM parent company affiliate GE Aviation Services at its Strother, Kansas, facility. By year-end 2013, the USAF will begin performing its own C-PUP upgrades at its Oklahoma City Air Logistics Complex and plans are in place to eventually reach a capacity of 120 engines per year.
In addition to significant mission benefits, the upgraded engine is transparent to the flight and maintenance crews; there are no field-level technical change orders that drive training requirements for pilots or maintainers on the flight line. Upgraded engines can be intermixed on the wing with the older configuration, allowing the upgrade to take place based on normal attrition, a key factor in keeping installation costs to a minimum
The C-PUP was certified in 2012. The U.S. Navy provided the aircraft/engine combination for the flight test program, with the USAF sharing the costs. The flight test engine performed so well, the Navy has kept it installed on the aircraft.
The first re-engined KC-135R tanker entered service in 1984 and nearly 2,000 CFM56-2 engines were delivered for the program. To date, more than 50 percent have yet to undergo a first shop visit.
Source: GE Aviation
Date: Feb 26, 2013