GE DEVELOPS F110, F414 ROADMAP
STANLEY W. KANDEBOJULY 171995
GE DEVELOPS F110, F414 ROADMAP
PROPULSION TECHNOLOGY
STANLEY W. KANDEBO
PARIS
General Electric plans to test an improved performance fan that could boost the durability of the F110-100 engine by as much as 30%.
The new, three-stage, integrally bladed disk (blisk) fan is based on the improvedefficiency, wide-chord-fan technology developed for the Fl18—the engine that powers the B-2 bomber.
The fan will be mounted on an Fl 101 29 improved performance engine for the test this September at GE's Evendale, Ohio, facility. If successful, the fan could be retrofitted into existing Fl 10-1 29s beginning as early as 1998. The FI 10s would receive the new fans as their current components near the end of their cyclic lives, Robert Griswold, FI 10 project manager, said.
General Electric and the U.S. Air Force hope to retrofit FI 10-129 powerplants with blisk fans to extend the engine's life and increase its resistance to foreign object damage. GE estimates that the Fl 1 8-derived fan could boost the life of the F1 1 0's core to 6,000 total accumulated cycles, an increase of 1,500 cycles from the current 4,500-cycle limit. If applied toward thrust, the increased-efficiency fan could boost engine power by about 15% compared with the Fl 10-1 29.
The company also is investigating a new radial augmenter for the Fl 1 0 and could begin developing the component before year-end. It would be based on technology developed for the YF1 20 engine that has already been incorporated into the F414, which will power the F/A-l 8E/F.
Radial augmentors use cooling air to reduce fuel spraybar temperatures and increase component life. The cooled spraybars also reduce coking, which improves component performance, Griswold said.
Taken together, the upgraded fan and the increased-durability augmenter constitute the first step of a three-step growth path. This plan details how the company's existing engines could be modified to satisfy current and evolving military propulsion requirements. Each of the improvements is directed at lowering maintenance or acquisition costs, improving specific fuel consumption or increasing thrust.
The improved FI 10 engine is being targeted at existing aircraft such as the F-15 and F-16. In addition to satisfying retrofit markets, GE believes new sales of these aircraft could develop if the Joint Advanced Strike Technology (JAST) program is delayed.
The second Fl 1 0 growth step builds on the first set of improvements. It swaps the existing Fl 1 0 core for one based on the CFM56-7 powerplant. Even though the existing FI 10 and CFM56-7 core engines have nearly the same airflow capacities, the newer CFM56-7 core is more efficient and therefore better poised for growth, Griswold said. Specifically, the CFM56-7 core would allow the company to moderately boost engine thrust without cooling the first stage of the lowpressure turbine.
Also being considered for inclusion in the second growth step is a new engine control system, which would be based on
technology defined for the YF1 20 and incorporated into the GE F414. According to Griswold, the F414's controller is the next step in technology. "It is a 'smarter' controller and has more diagnostic capability to reduce maintenance costs."
THE NEW CONTROLLER and increased-efficiency core together could boost FI 10 thrust as much as 20-25% beyond that of the current FI 10-129, allowing the powerplant to generate as much as 36,000 lb. of thrust. Even more thrust could be generated if the FI 10 incorporated some variable engine features, he said.
The company's third projected growth step would allow the FI 10 to produce nearly 40,000 lb. of thrust by adding an
increased airflow blisk fan. The diameter of this higher airflow fan would be larger than that of the current Fl 10-1 29, departing from the strategy of the first two
growth steps. Adding the larger diameter fan would change the installation diameter of the upgraded Fl 1 0 and require aircraft fitted with the new engine to have a higher flow inlet. The need for a bigger inlet would severely limit or exclude use of the upgraded engine in existing airframes. Consequently, the real market for the powerplant would be a conventional version of JAST, Griswold said.
In addition to defining a roadmap for its FI 10 engine, GE has tentative plans for increasing the thrust of its F414 powerplant. The first step would be to raise engine thrust by about 1 0% around 2005.
This would be accomplished by increasing engine temperatures and adding higher temperature turbine alloys to maintain component life, Dennis Williams, vice president and general manager of GE Aircraft Military Engines, said.
THE COMPANY ALSO WOULD add an allblisk compressor. Integrally bladed disks are currently used in the first three stages of the F414's seven-stage compressor.
The second of the F414's projected growth steps would provide about 15% more thrust than today's F41 4. GE engineers would accomplish this by combining the improved core developed under the first growth step with a larger fan and a new low-pressure turbine. Despite the thrust increase, the engine would continue to fit into the F/A-l 8 E/F's installation envelope.
The final step would target an engine in the 29,000-lb.-thrust class. To generate this thrust level, the engine would maintain the core and fan developed under the earlier growth steps and add a new two-stage low-pressure turbine. Afterburner and nozzle modifications also would be necessary.
Markets for this engine could be a new aircraft or a significantly modified version of the F/A-l 8E/F that featured a new inlet, Williams said.
