Hermeus has unveiled its latest plans for the Quarterhorse supersonic aircraft, which will be used to launch a high-Mach test vehicle called Ramjet-X. The new platform will allow clients to test components under realistic high-speed flight conditions.
The Quarterhorse project began as a plan by Hermeus to radically speed up aircraft development and flight testing by building one prototype per year to test a specific part of the flight envelope while the next iteration was already in development.
This rapid-prototyping approach resulted in the Mk 0, which was built solely for ground taxi tests. This was followed by the uncrewed Mk 1, built in just seven months to test low-speed takeoff and landing. Then came the Mark 2.1, which was about the size of an F-16 and went supersonic only a year later.
Now, Mark 2.2 and Mark 2.3 are in the works, but this raises the question of how does Hermeus monetize the platform once it becomes operational?
That’s where Ramjet-X comes in. Ramjet engines can be perplexing the first time you look at one. It looks like an empty metal tube with none of the moving parts you’d expect to see in a conventional jet engine. There’s no fan, no turbines, no drive shafts, no nothing except for nozzles for injecting fuel into the tube.
This is because a ramjet uses the forward velocity of the aircraft to compress the air as it enters the engine, heating it, and then igniting the air/fuel mixture. It’s remarkably efficient and overcomes many of the problems of flying supersonic up to about Mach 6, but it suffers from the fact that it first has to be moving at Mach 1.5 to compress the air enough to function.
To do this, a ramjet has to be accelerated by a separate rocket engine or the equivalent. That is where Quarterhorse comes in.
By using a supersonic variant of Quarterhorse as a reusable mothership, Hermeus plans to carry Ramjet-X to high altitudes and accelerate it to ignition speeds. Once released, Ramjet-X will ignite its ramjet, accelerating to high-Mach velocity while sending back real-time telemetry throughout its one and only mission.
According to the company, Ramjet-X is designed to deliver a “Flight Test as a Service” (FTaaS) platform. It will allow commercial and government clients to test sensors, communications systems, high-temperature materials, autonomy software, and propulsion technologies under sustained high-Mach conditions without building their own expensive test vehicles.
Ramjet-X engine testing is currently underway at the Hermeus High-Altitude Engine Test (HEAT) facility in Jacksonville, Florida, while development of its high-temperature structures takes place in El Segundo, California. Flight testing is slated for 2027.
“High-speed flight testing is extremely expensive, and you don’t get many shots at it,” said Zach Shore, CEO of Hermeus. “Ramjet-X gives us a way to put new systems into sustained high-Mach environments without building an expensive one-off test program every time. Bringing speed, sustained flight, and scalability all into one system lowers the barriers to gathering extremely valuable data from these conditions and accelerates programs for both us and our customers.”
Source: Hermeus
