General Electric XA102

The U.S. Air Force and U.S. Navy began pursuing adaptive cycle engines in 2007 with the Adaptive Versatile Engine Technology (ADVENT) program, a part of the larger Versatile Affordable Advanced Turbine Engines (VAATE) program. This technology research program was then followed by the Adaptive Engine Technology Demonstrator (AETD) program in 2012, which continued to mature the technology, with tests performed using demonstrator engines. GE's ground demonstrator consists of a three-stage adaptive fan and a high pressure compressor derived from CFM LEAP's ten-stage compressor; the tests in 2015 yielded the highest combined compressor and turbine temperatures in the history of jet propulsion. The follow-on Adaptive Engine Transition Program (AETP) was launched in 2016 to develop and test adaptive engines for sixth generation fighter propulsion as well as potential re-engining of the F-35 from the existing F135 turbofan engine. The demonstrators were assigned the designation XA100 for General Electric's design and XA101 for Pratt & Whitney's. While the XA100 and XA101 became focused on the potential re-engine of the F-35, a separate engine program was initiated for the Air Force's Next Generation Air Dominance fighter, which is expected to be optimized differently with a greater emphasis on supersonic cruise (or supercruise) performance; this program became the Next Generation Adaptive Propulsion (NGAP) and the entrants were the General Electric XA102 and Pratt & Whitney XA103. Critical design review of the XA102 was completed in December 2023, and flight testing is expected to begin in the late 2020s. ==Design==

The XA102 is a three-stream adaptive cycle engine that can adjust the bypass ratio and fan pressure to increase fuel efficiency or thrust, depending on the scenario. It does this by employing an adaptive fan that can direct air into a third bypass stream in order to increase fuel economy and act as a heat sink for cooling. The increased cooling and power generation also enables the potential employment of directed energy weapons in the future. When additional thrust is needed, the air from the third stream can be directed to the core and fan streams. In addition to three-stream adaptive cycle configuration, the engine also uses new heat-resistant materials such as ceramic matrix composites (CMC) to enable higher turbine temperatures and improved performance. ==Applications==

• Next Generation Air Dominance (planned) ==Specifications (XA102-GE-100)==