The Next Great Engine War Was Not What You Thought It Was
for high-speed performance to high for cruise, by using a third stream of air separate from the combustor and traditional bypass flows. Depending on flight conditions, the third stream can be increased or decreased to adjust the bypass ratio. In 2007, after a short initial contract requiring P&W, GE, and RR to explore conceptual designs for notional aircraft applications, the Air Force awarded a $296 million contract to RR and a $231 million contract to GE to proceed into the design and ultimately demonstration (Flight Global, 2007). Although not explicit, the contract served as a concessionary prize to partially make up for the termination of the F136. Since the Air Force did not have sufficient funding to fully fund both contracts, the contracts contained a clause stating that the Air Force would provide authorization to proceed into the demonstration portion of the contract based on technical viability and available funding. P&W’s bid was unsuccessful, meaning the company would have to devote internal research and development funds to continue adaptive engine work or risk losing the dominance it enjoyed with the F135. As the GE and RR design teams progressed, the program continued to gain visibility and prominence. With the DoD desiring both companies to achieve technical parity, additional funds were reallocated to ensure that both contractors could test a demonstrator engine. Still, AFRL required each team to test the engine's core. The core consists of the high- pressure compressor, combustor, and turbine. GE successfully tested its core in late 2012, achieving records for the highest pressure ratios and temperatures the Air Force has ever tested (Jordan, 2014). Meanwhile, in 2012, plans for a follow-on program, Adaptive Engine Technology Development (AETD), were being conceived. Politics played a prominent role in the follow-on, with the F136 battle recently concluding with
116
Defense ARJ , Summer 2025, Vol. 32 No. 2: 104—130
Made with FlippingBook - Online Brochure Maker