USAF Advances Adaptive Engine Technology Development Program
GE Aviation and Pratt and Whitney both invited to negotiate a program for new foundations for engines with better fuel efficiency. US Manufacturers will be source of new precision parts made with new materials, such as ceramic matrix composite.
In a bid to develop a new class of engines with 25% better fuel efficiency, the US Air Force is launching its new Adaptive Engine Technology Development. Its goal is to develop a new class of engines that use variable cycles rather than a fixed cycle. Air Force Magazine (Grant, 9/12) describes an adaptive engine as one that “varies the airflow and pressure ratios in the engine. Aircrews can then toggle between fuel-efficient cruise modes and thrust for high-speed and even supersonic flight.” Think high bypass ratio engines in civilian airliners and the high thrust, low bypass ratio engines of jet fighters. A variable cycle engine would combine both. The article goes on to say that this simple idea requires a string of refinements and
inventions.
Enter Adaptive Engine Technology Development (AETD) program and the negotiations with both GE Aviation and Pratt and Whitney. The AETD program is designed for future strike, bomber and tactical aircraft.
According to a September 17, 2012 GE Aviation press release, the company has developed variable cycle technology for more than 30 years, beginning with the YF120 for the USAF's Advanced Tactical Fighter project and continuing with the current ADaptive Versatile ENgine Technology (ADVENT) program, which will conclude in 2013 after full engine testing. GE's adaptive engine approach has internal variable features that adjust bypass ratio and pressure ratio to optimize operation for a wide range of flight conditions. Technologies demonstrated through ADVENT that will be validated by AETD include an adaptive three-stream fan, third stream-cooled cooling air, and ceramic matrix composite (CMC) materials. The company claims these improve power extraction, thermal management and inlet recovery while reducing installed drag.
Development work will be conducted at GE Aviation’s headquarters in Evendale, Ohio. Once negotiations are complete and award is made, GE will share the costs of the program with the Air Force.
Phase 1 of the GE Aviation AETD program, which runs through mid-fiscal year 2015, includes completing preliminary engine design, testing a full annular combustor rig, high-pressure compressor rig and components using CMCs. Phase 2 of the program, which will conclude in fiscal year 2016, consists of fan rig testing and a full engine core test, allowing for a notional first full engine test as early as 2017.
Pratt & Whitney was also selected for negotiations for AETD. The goal for P&W is to merge innovative adaptive engine and next generation technologies with the best features of its F119 and F135 engines, according to a September 18 press release from the company.
P&W’s proposed AETD program will lead to demonstration testing of an advanced high pressure ratio core in late 2015, to be followed in 2016 by full engine testing of a three-stream adaptive fan and three-stream compatible augmentor and exhaust system. According to P&W, “the introduction of the third flow path stream will allow the engine operating conditions and resultant bypass ratio to be modulated to optimize performance across all power settings and flight conditions.”
According to the Air Force magazine article, the US Air Force is funding the program at $213.6M in the first year. Why is this important to manufacturing? As the article succinctly states “Most of the work is under export control. Primes [will] therefore use almost exclusively a slate of highly specialized US suppliers for tasks from precision castings to manufacture of blisks, airfoils, fuel pumps, and even fasteners. Dollars spent on advanced propulsion help fuel cutting-edge US manufacturing.”