Hermeus has secured a production licence from Pratt & Whitney, an RTX business, to manufacture the F100-PW-229 fighter engine, creating a new qualified U.S. production source for one of the military’s most widely fielded propulsion systems. The agreement, unveiled in Los Angeles on 15 September, links the hypersonic aircraft developer’s Quarterhorse programme with a legacy combat engine used across U.S. fighter fleets.
Under the arrangement, Hermeus will apply its rapid-build manufacturing approach while meeting Pratt & Whitney’s quality, safety and site-activation standards. The partnership is intended to expand domestic engine capacity and strengthen supply resilience for the F100 line, which powers the Quarterhorse aircraft. Hermeus’ Quarterhorse Mk 2.1 reached supersonic flight earlier in 2026, and the company becomes the first vertically integrated airframer with in-house propulsion capability to scale the programme.
The deal also broadens the industrial significance of the engine beyond Hermeus’ own aircraft development. Public details on production volume, delivery timing and customer demand were not disclosed.