We have constructed and actually flown in the real world a full-size flight demonstrator and we set world records in the process. Will Roper wrote at the Air, Space and Cyber Conference 2020, and that single line alone needs no further elaboration to clarify the degree of confidence the F-47 was said to have than a tower of artist impressions would.
The loudest of such takes are around the F-47: shaping, stealth, sensors, and what is often called the fallacy of declaring that a sixth-generation “fighter” is already pursuing the challenges of yesterday. The more serious, lower-keyed narrative, lies behind the lips of the inlet. The propulsion program that the F-47 is being developed under, Next-Generation Adaptive Propulsion (NGAP) is the point where the Mach-and-range promises of the F-47 no longer sound like marketing and begin to look like math of design.
NGAP is a two horse race between engines, XA102 and XA103 adaptive cycle of GE Aerospace and Pratt and Whitney respectively. The Air Force has also indicated that it intend to go that far in order to develop entire prototypes before winnowing the field. The contract arrangement indicates that aim: maximums per engine work have been increased to $3.5 billion and the work schedule is extended to July 2032, an extended runway corresponding to the technical aspiration of variable-cycle hardware and control software.
Adaptive-cycle engines are important in the sense that they strike on the most ancient of trade of the fighter designer, namely, thrust when you need to sprint, efficiency when you need to loiter, and heat management when the electronic of the jet itself is about to boil itself. The leverage was publicly demonstrated through the XA100 work of GE that was developed as part of the Adaptive Engine Transition Program. A three-stream design enabled the alternate operation between high-thrust and high-efficiency modes with purported results of 25 percent improved fuel efficiency, 30 percent increased range, and 25 percent improved acceleration. The same technology family achieved an even less glamorous yet even more decisive metric: it doubled mission-systems cooling capacity, the sort of thing that has a direct impact on sensor work, electronic warfare duty cycles and time-on-station.
That cooling statement is not a footnote; it is an enabler of design. The road to sixth-generation capability is becoming narrower and narrower due to the fact that thermal bookkeeping – managing waste heat in the computing, sensors, and apertives operating with high power and without advertising the aircraft as present – is a limiting factor. The keyline innovations of propulsion outlined about these adaptive engines – additively machined heat exchangers, rotating ceramic matrix composite components, and computerized engine control, are like a list of things put on the checklist to solve that issue, not a list of things put on the checklist to achieve headline top speed.
All this does not seem to be occurring on paper alone. According to DARPA, on risk-reduction contracts, Boeing and Lockheed Martin had developed NGAD X-planes, that initially flew in 2019 and 2022 and had accumulated several hundred hours each. Gen. David Allvin, the Chief of Staff of the Air Force, put it bluntly about what those flights accomplished in the past five years: The X-planes of this plane have been secretly laying the groundwork of the F-47, over five hundred hours, experimenting with the latest thinking, and demonstrating that we can drive the envelope of technology and know the results.
The concept of the platform of the F-47 is also based on the assumption that it will not be fighting alone. The Air Force is developing Collaborative Combat Aircraft that will have the capability to fly with crewed fighters and increase sensing, jamming, and weapons capacity; Congress has mandated funding of CCA development amounting to 678 million in FY2025. With such a framing, the efficiency and thermal gains of NGAP do themselves generate margin, electrical, cooling, and fuel, to enable the F-47 to act as a controlling node to uncrewed teammates and still be able to accelerate, reposition, and survive.
That is, the propulsion story of the F-47 is not something that was attached to the plane. It is the portion which renders the rest of the idea physically possible.
