Hermeus developing air-launched disposable hypersonic test vehicle

Hermeus has disclosed that it is developing an expendable flying testbed powered by a ramjet, called Ramjet-X. The California-based hypersonic aircraft company will carry the vehicle aloft on its reusable Quarterhorse aircraft and release it in mid-air.

Ramjets need high initial speed before they can operate. Rather than use a large expendable booster for every test, Hermeus plans to have Quarterhorse carry the testbed to launch speed and altitude, release it, then return to base for further flights. The company said the approach is meant to support high-Mach "Flight Test as a Service," in which customers install payloads, sensors, communications and computing equipment, autonomy software, material samples and propulsion systems on the vehicle for assessment in sustained high-Mach conditions.

According to the company, a platform that can be flown repeatedly lets customers focus on the technology under test instead of building a one-off vehicle for each experiment.

Chief executive Zach Shore said high-speed flight testing is very costly and offers few opportunities. The programme, he said, provides a way to place new systems in sustained high-Mach environments without mounting an expensive single-use test effort each time.

Work on Ramjet-X continues. Its engine is being tested at the company's HEAT facility in Jacksonville, Florida, and high-temperature structures are in development at its El Segundo headquarters. Integrated vehicle testing is scheduled for 2027.