Japan's Kayaba Industry developed the Heliplane gyrodyne prototype from 1952-1954, combining autogyro and helicopter features with rotor-tip ramjets and a Cessna 170B airframe. The project received government and corporate funding but was abandoned in July 1954 after damage during ground testing before the aircraft could fly.
Hermeus announced Ramjet-X, a low-cost expendable ramjet-powered test vehicle launched from its reusable Quarterhorse aircraft to achieve high-Mach flight. The system will enable Hermeus to offer flight testing as a service, allowing customers to test payloads and experimental hardware in sustained high-speed conditions without developing bespoke test programs. Development is underway with engine testing in Jacksonville and integrated vehicle testing planned for 2027.