- The Ramjet-X developed by Hermeus is designed for high Mach speed flight.
- Ramjet-X reduces the cost and barrier to entry for high-speed flight testing.
- Customers can integrate various technologies into Ramjet-X for testing.
- Challenges of high Mach flight include aerodynamic heating and propulsion efficiency.
A Los Angeles-based company is developing a low-cost, disposable ramjet-powered vehicle designed to be launched from its Quarterhorse aircraft. Named Ramjet-X, the vehicle is capable of flying at high Mach speeds. Hermeus has revealed that ramjet engines require a certain initial speed to operate effectively. Therefore, Hermeus will use its reusable Quarterhorse aircraft to accelerate Ramjet-X to the necessary speed and altitude for launch, eliminating the need for large, expensive disposable boosters for each test.
Once released, Ramjet-X will begin its ramjet-powered flight while the Quarterhorse returns for future flight test missions.
Ramjet-X Reduces Testing Costs
Hermeus CEO Zach Shore stated, "The cost of high-speed flight testing is extremely high, and the opportunities for testing are limited. Ramjet-X provides us with a way to introduce new systems into a sustained high Mach environment without having to create an expensive one-off test program each time. Integrating speed, sustained flight, and scalability into a single system lowers the barrier to obtaining highly valuable data from these environments and accelerates our projects and those of our customers." Ramjet-X will also enable Hermeus to offer Flight Test as a Service (FTaaS), expanding access to flight environments that have historically been costly and difficult to reach.
Customers and partners can integrate payloads, sensors, communications and computing systems, autonomous control, material samples, propulsion technologies, and other experimental hardware and software into Ramjet-X for testing under representative sustained high Mach conditions.
Engineering Challenges of High Mach Flight
According to the press release, by providing a reusable platform, launch architecture, and flight test infrastructure, Hermeus allows customers to focus on the technologies being evaluated without having to develop a unique high-speed vehicle and test program for each experiment. The development of Ramjet-X is already underway, with Hermeus testing the ramjet engine of Ramjet-X at its HEAT facility in Florida, while high-temperature structures are being developed at its headquarters in El Segundo, California.
Integrated vehicle testing is currently planned for 2027.
The engineering challenges of high Mach flight go far beyond making an aircraft fly faster. At extreme speeds, aerodynamic heating becomes a major issue. Structures, sensors, propulsion systems, and other components must operate while encountering temperatures and pressures vastly different from those of conventional aircraft. Propulsion is also a significant challenge. For example, ramjet engines cannot operate efficiently from a standstill and must rely on the forward motion of the vehicle to compress incoming air before introducing fuel and igniting it. This means that ramjet-powered vehicles need to reach sufficiently high speeds for their propulsion systems to work effectively.
Hermeus' solution is to use another aircraft as an accelerator.
Ramjet-X is also closely related to Hermeus' work on air-breathing high-speed propulsion. The company is developing turbine-based combined cycle propulsion technology, which uses different propulsion modes at different stages of flight. For example, Hermeus' Chimera engine combines turbine and ramjet concepts, allowing the propulsion system to operate across a wider speed range. At lower speeds, the turbine engine provides the necessary thrust. As the aircraft accelerates and conditions become suitable for ramjet operation, the airflow can be redirected to make the ramjet the primary propulsion source.
This is crucial because a pure ramjet-powered aircraft cannot take off from a runway and accelerate from zero to its optimal operating speed on its own; it needs an initial push. Ramjet-X effectively addresses this issue from the other direction: rather than requiring the test vehicle to provide all the acceleration, a reusable aircraft provides the initial speed.
How Ramjet-X is Changing the Hypersonic Testing Paradigm
The development of Ramjet-X marks a significant shift in hypersonic testing, significantly reducing the cost and complexity of testing by using a reusable aircraft as an accelerator. This not only enables more customers to conduct tests in high Mach environments but also facilitates the rapid validation of new technologies. As the demand for high Mach flight increases, addressing the challenges of propulsion systems and aerodynamic heating becomes particularly important. The design of Ramjet-X is capable of effectively tackling these challenges, paving the way for future advancements in aerospace technology.