EVENDALE, Ohio - GE Aircraft Engines' new LO Axi (Low Observable Axisymmetric) Exhaust System was successfully tested recently at the Air National Guard Base at Joe Foss Field in Sioux Falls, S.D.
This is the first step in the LO Axi Exhaust System demonstration testing being conducted under the Joint Strike Fighter (JSF) Technology Maturation Program to verify advanced, affordable technologies applicable to the JSF.
During this test, GE's flight-ready LO Axi Nozzle was installed by the South Dakota Air National Guard in an F-16C and ground-tested to verify installation compatibility with an operational aircraft system. Both infrared (IR) and radio frequency (RF) measurements were made by GE Aircraft Engines (GEAE) with the F110-GE-100 engine operating at power settings ranging from idle to maximum afterburner. The resulting test data verified that the LO Axi Nozzle achieves its installed signature goals during operation.
Under the JSF contract, additional engine testing is currently taking place to verify maturity of the LO Axi Exhaust System. This durability test consists of a block of over 500 hours of Accelerated Mission Testing (AMT) on an F110-GE-129 engine at the GEAE facility in Evendale, Ohio. Follow-on flight demonstration testing is planned for 1997-98.
GE's LO Axi Nozzle is a low-cost, lightweight means of achieving signature control while providing significant improvements in reliability, maintainability, and supportability, compared to current production nozzles. Advances in radar cross section (RCS) design and materials technology allow axisymmetric nozzles to achieve signature levels previously possible only with two-dimensional (2-D) nozzles.
Advantages of axisymmetric designs, attributable to inherent structural simplicity and efficiency, have been employed to achieve substantial weight and cost reductions compared to 2-D designs. In addition to geometrical shaping and special materials for signature control, the LO Axi Nozzle also incorporates an ejector that enhances nozzle cooling. Durability has been significantly improved, and maintenance-friendly features reduce the time required to change components by as much as 80 percent.
A joint effort by a Lockheed Martin/GEAE team modified the F-16 to accommodate the LO Axi Nozzle ejector. In expressing Lockheed Martin's interest in this test, Carl McMurry, Program Manager, F-16 Advanced Exhaust Systems, said, "GE's low-cost, lightweight LO Axi Nozzle significantly reduces signature levels and is also low-risk because it is a modification of the current production F110 engine nozzle, which has millions of flight hours of experience behind it."
Total test time on the LO Axi Nozzle continues to accumulate. The F-16 ground test in Sioux Falls added 8.5 hours of run time, with over 3 minutes at maximum afterburner. Including F110 engine test time under an earlier Joint Technology Demonstrator Engine (JTDE) program, the LO Axi Nozzle total run time is now 14 hours, with 21 minutes at maximum afterburner. The exhaust system hardware and materials remain in excellent condition.
Summarizing the test program, Phil Combs, JSF Program Manager for the GE/Allison/RR Team, said, "This successful effort is an example of the high payoff technologies applicable to current and advanced weapon systems that GE and our teammates are pursuing through joint activities. Demonstrations such as this verify that advanced signature and propulsion technology is available to significantly enhance the capabilities of today's weapon systems while also ensuring that next-generation aircraft, such as the JSF, will meet design goals at affordable cost and risk levels."