America’s iconic F-15 and F-16 fighters are getting a new engine source

Pratt & Whitney has licensed aerospace startup Hermeus to manufacture F100-PW-229 turbofan engines, creating a new U.S. production source for one of America’s most widely used fighter engines. The agreement allows Hermeus to manufacture the F100 under Pratt & Whitney’s production standards while using its own rapid-build manufacturing approach. The companies say the move will expand domestic engine capacity and strengthen the U.S. defense industrial base. Breaking Defense reported the agreement, which covers the F100-PW-229 used by versions of the F-15 and F-16. Pratt & Whitney says the F100 family has accumulated more than 30 million flight hours and powers aircraft operated by 23 air forces. Hermeus becomes a second F100 production source The F100-PW-229 entered operational service in 1992 and remains in service with the U.S. fighter fleet. Pratt & Whitney says the engine is compatible with the F-15EX and remains in production to support existing and future aircraft. For Hermeus, the agreement also solves a specific problem. Its Quarterhorse unmanned aircraft uses the F100, allowing the company to bring engine manufacturing closer to its airframe production rather than relying entirely on an outside supplier. Hermeus CEO Zach Shore told Breaking Defense that the company will initially use its existing production facilities and views the arrangement as becoming an extension of Pratt & Whitney’s manufacturing operation. He also said production levels and investment will ultimately depend on customer demand. The company is not positioning itself as a clean-sheet fighter-engine manufacturer. Instead, it will produce an established engine under license while applying its own manufacturing processes within that agreement. Demand for fighter engines is rising The timing reflects growing demand for engines across the U.S. tactical-aircraft fleet. According to Breaking Defense, an August Air Force request for information projected peak demand for F100 engines could exceed 180 annually by fiscal year 2034, including requirements for F-15EX and F-16 aircraft operated by the United States and international customers. The Air Force said it was seeking greater manufacturing innovation and supply-chain resilience. A second production source could therefore give Pratt & Whitney additional capacity while reducing dependence on a single manufacturing pipeline. The F100 also has potential relevance to newer unmanned aircraft. Pratt & Whitney’s own F100-PW-229 material describes the engine as suitable for current F-15 and F-16 aircraft as well as new fighter and unmanned platforms. For Hermeus, Quarterhorse provides the immediate application. The company is developing the unmanned aircraft for high-speed flight under a $219 million Defense Innovation Unit contract, with the eventual goal of reaching speeds up to Mach 3. Hermeus is also developing its own turbine-based combined-cycle propulsion technology, known as Chimera, for future high-speed aircraft. That system combines turbine and ramjet propulsion concepts and is separate from the licensed F100 production effort. The new agreement therefore gives Hermeus an unusual position for a relatively young aerospace company: it can manufacture a mature fighter engine while continuing to develop its own high-speed aircraft and propulsion technologies. For Pratt & Whitney, meanwhile, adding another American manufacturer could provide a way to expand F100 production as demand grows without creating an entirely new engine production line. The companies have not disclosed a production rate or specific start date for Hermeus-built F100 engines. But the agreement marks a significant expansion of the F100 industrial base and gives Hermeus a new role in sustaining one of America’s longest-serving fighter engine families. Get the latest in engineering, tech, space & science - delivered daily to your inbox.Kaif Shaikh is a journalist and writer passionate about turning complex information into clear, impactful stories. His writing covers technology, sustainability, geopolitics, and occasionally fiction. A graduate in Journalism and Mass Communication, his work has appeared in the Times of India and beyond. After a near-fatal experience, Kaif began seeing both stories and silences differently. Outside work, he juggles far too many projects and passions, but always makes time to read, reflect, and hold onto the thread of wonder.