Lead Propulsion Component Engineer

Hermeus unveils low-cost ramjet vehicle to democratise high-mach flight testing. The US-based Hermeus is developing a low-cost, expendable ramjet vehicle that could make sustained high-Mach flight testing faster, cheaper, and more accessible worldwide to researchers and industry alike in coming years ahead. September 15, 2026 LOS ANGELES. Hermeus is developing a new expendable, ramjet-powered vehicle designed to provide sustained high-Mach flight testing without the cost and complexity of building a bespoke aircraft for every experiment. Called Ramjet-X, the vehicle will be released from the company's reusable Quarterhorse aircraft after being carried to the speed and altitude required for ramjet operation. Once released, Ramjet-X will ignite its air-breathing engine and continue under ramjet power, while Quarterhorse returns to base for future missions. The architecture addresses one of the basic limitations of ramjet propulsion: a ramjet cannot produce useful thrust from a standstill. Unlike a turbojet, it has no compressor driven by a rotating turbine. Instead, it relies on the vehicle's forward speed to compress incoming air before fuel is injected and burned. That means a ramjet-powered vehicle first needs an external boost. Traditionally, this has involved a rocket booster, another aircraft or a large, expendable launch system. Hermeus says using a reusable Quarterhorse aircraft as the accelerator could make repeated tests more economical and operationally practical. The company has not disclosed every performance parameter for Ramjet-X, including its precise top speed, range or payload capacity. However, its stated purpose is to operate in sustained high-Mach conditions, creating a platform for testing propulsion systems, sensors, communications equipment, materials, autonomy software and other aerospace technologies. "High-speed flight testing is extremely expensive, and you don't get many shots at it," Hermeus chief executive Zach Shore said. The company believes Ramjet-X can reduce that barrier by offering a repeatable test vehicle rather than requiring customers to develop an entire high-speed aircraft programme for each experiment. Hermeus plans to offer the capability as high-Mach Flight Test as a Service. Customers would be able to install experimental payloads and gather data in an environment that is difficult to recreate in wind tunnels or computer simulations. The model could appeal to defence contractors, research institutions, space companies and manufacturers developing components for fast aircraft and missiles. Ramjet-X is also connected to Hermeus's broader work on combined-cycle propulsion. Its Chimera engine concept combines turbine and ramjet technologies, allowing different propulsion modes to operate at different stages of flight. A turbine can provide thrust at lower speeds, while the ramjet takes over after the vehicle reaches conditions suitable for high-speed air-breathing propulsion. The distinction is important because a purely ramjet-powered aircraft cannot simply take off from a runway and accelerate through the lower-speed regime. Ramjets generally become useful only after achieving substantial forward velocity and perform most efficiently at supersonic speeds. They can operate at much higher speeds, but aerodynamic heating, material durability, fuel control and stability become progressively more difficult. Hermeus is conducting Ramjet-X engine testing at its HEAT facility in Jacksonville, Florida, while engineers develop high-temperature structures at the company's headquarters in El Segundo, California. Integrated vehicle testing is currently planned for 2027. The programme's most significant promise may be its economics. High-speed flight research has traditionally depended on expensive, limited-use aircraft, large test ranges and lengthy preparation cycles. An expendable vehicle could eliminate refurbishment after each mission, while the reusable carrier could lower the cost of getting the test article airborne. There are substantial risks. The company must prove that Ramjet-X can survive severe aerodynamic heating, maintain stable propulsion and transmit useful data during a demanding flight. It must also demonstrate that its reusable launch architecture can operate reliably and safely. If successful, however, Ramjet-X could turn high-Mach testing from an occasional national programme into a more accessible commercial service - giving aerospace developers more opportunities to test, fail, improve and fly again.

Hypersonic aircraft startup adding Anduril's autonomy software for 2027 flight. Startups Anduril Industries and Heremus have agreed to integrate Anduril's autonomy software onto Hermeus' hypersonic demonstrator aircraft "Quarterhorse" - uniting two technologies that have drawn keen interest and investment from the Air Force. The firms announced the deal Sept. 3 and said they plan to fly the Quarterhorse Mk 2 aircraft using the Lattice autonomy system in 2027. Hermeus is attempting to build a reusable aircraft that can reach hypersonic speeds, defined as Mach 5 and above, and has received funding and support from the Air Force. Quarterhorse has yet to go that fast - company officials say they're targeting supersonic speeds, or Mach 1-plus, as the next step in their test campaign - but adding autonomy software could enable faster control of the aircraft as it flies around a mile per second. At the same time, preparing the software for the platform will take time. "We will spend the rest of this year on a build-up from software in the loop to integration testing to hardware in the loop and validation testing, then we'll go toward flight," Brett Darcey, vice president for mission autonomy at Anduril, told Air & Space Forces Magazine. Anduril is already refining its autonomy software, dubbed Lattice, for the Air Force's Collaborative Combat Aircraft program. The firm is competing with Shield AI and Collins Aerospace on that front. Anduril is also building its FQ-44A Fury drone as one of the CCA airframes, along with General Atomics' FQ-42A Dark Merlin. But while Anduril has experience with the CCA program, CCAs aren't meant to be supersonic nor hypersonic like Quarterhorse. The speeds at which that aircraft will operate will require beyond human-like decision-making speeds. The Autonomy Government Reference Architecture that serves as the baseline for most contractor's autonomy software requires that Quarterhorse be able to fly itself "through all regimes of flight, which would include the jump to supersonic," Darcey said. That means human operators will tell the software to fly at a certain velocity, and the software will be responsible for taking the steps to execute the command. "That probably means we're going to do a lot of software and hardware in the loop testing, and a lot of independent validation of what we are doing on the route generation side, and appropriately, I think the monitoring of execution of those routes when we're at those high speeds on the build-up phase all the way to flight," Darcey said. That step-by-step approach is necessary as companies work to build trust in the software's ability to control the aircraft's flight and other taskings for its human operators. Tactics, techniques, and procedures are still developing and evolving to build that trust between human and machine, but Darcey was quick to note that in the development stage there can be too little trust; at times, there can also be too much. He likens it to using an actual horse in warfare. Horses are independent, thinking creatures that can also be trained to do certain things. Cavalrymen would build their trust in the "human-horse system" over time, instead of just jumping on a horse and going to war. A key difference between autonomy software and an actual horse, though, is that the software has built-in debrief functions that will tell the user what it did and why. And as developers of the software, sharing that data with their company partners and the Air Force provides transparency for the process, Darcey said. CCA and mission autonomy. In February, Anduril's developmental YFQ-44A flew with two different mission autonomy software suites on the same aircraft during the same flight, using both Lattice and Shield AI's Hivemind suite. "We do have an advantage with Fury," Darcey said. "That kind of deep platform knowledge definitely is useful." But Darcey was quick to point out that the company isn't tying all its software thinking to its own platform, or even to a single platform. The software used in the CCA program must also be viable for a wide range of aircraft types, based on USAF requirements. "One of the big challenges with mission autonomy is it has to be generally built so it can do the mission requirements of multiple platforms at once," Darcey said. Quarterhorse. Hermeus conducted its first flight with the Mk1 model in May 2025 and then flew its Mk 2.1 demonstration vehicle in another flight in March. That flight ran from Spaceport America past White Sands Missile Range, N.M., with operators piloting the aircraft from a ground-based flight deck, Air & Space Forces Magazine reported. The Mk 2 aircraft is roughly the size of an F-16 fighter. The company won a $1.5 million contract in 2020 for a future hypersonic Presidential and Executive Airlift fleet via AFWERX, an Air Force innovation arm within the Air Force Research Laboratory. In 2021, Hermeus won a $60 million Strategic Funding Increase contract via AFWERX and the Air Force Life Cycle Management Center The Defense Innovation Unit awarded Hermeus a $23 million contract in 2023 for technologies related to the unit's larger goal of creating a Hypersonic High-Cadence Airborne Testing Capabilities program. Air, Technology, Anduril, Anduril Industries, Anduril Lattice, autonomy software, Hermeus, mission autonomy, Quarterhorse, software Air & Space Forces Magazine [crypto-donation-box type="tabular" show-coin="all"]

Exclusive: Hermeus unveils Ramjet-X, a "high-Mach" aircraft. Colin Demarest Wed, September 9, 2026 at 3:20 AM PDT * Hermeus is developing Ramjet-X, a super-fast aircraft that serves as a test bed for propulsion and materials science, offering high-Mach flight test as a service. Hermeus is building what it's calling Ramjet-X - a super-fast aircraft that blurs the line between large drone, air-defense target and test bed for propulsion and materials science. Why it matters: It's another big bet on unmanned speed from the company, which this year was valued at $1 billion post-money and moved its headquarters from Georgia to California. Driving the news: Hermeus unveiled Ramjet-X this morning, offering the defense world "high-Mach flight test as a service" and highlighting the national-security insights that come with it. * "I can monetize this as a test asset - B2B, B2G. But it's also an in-house test asset that gets me ramjet flight data and long-duration thermal management flight data now," chief executive Zach Shore told Axios. * "This can seriously drop testing costs, and also advance our propulsion work." Zoom in: Ramjet-X, about 22 feet long and 7 feet across, is designed to launch midair from underneath Quarterhorse, the F-16-sized unmanned aircraft that Hermeus is known for. * First flight of Ramjet-X is expected less than a year from now. Eventually, one Quarterhorse will be able to carry two Ramjet-Xs slung underwing, according to Shore. * "The first-stage booster is the airplane," he said. * "When the plane gets up to Mach 3, I can release a ramjet-only system that's going to accelerate, climb, get up to about 100,000-ish feet, Mach 4-ish speed, and it's going to cruise for tens of minutes." The intrigue: There are echoes of the Cold War-era D-21, M-21 and piggybacking configuration here. * "There is a very clear historical precedent that's really exciting," Shore said. * "Things that we thought were impossible, that we did in the '60s with slide rules - we can do them again." What we're watching: Which companies sign up, and where this endeavor intersects with Pentagon programming, like the Multi-Service Advanced Capability Hypersonics Test Bed. The bottom line: "It's very early, but people are definitely intrigued," Shore said. "Tomorrow is now today."