The company behind the design wants to build reusable hypersonic airplanes at Mach 5 speeds.
The Details
Hermeus, a start-up company building a reusable hypersonic aircraft, signed a $60 million partnership contract with the United States Air Force to further test and develop the company’s Quarterhorse aircraft, powered by a single turbine-based combined cycle engine.
“Quarterhorse will validate the company’s proprietary turbine-based combined cycle (TBCC) engine, based around the GE J85 turbojet engine, and is the first in a line of autonomous high-speed aircraft,” explained the aerospace company in a statement on the recent contract award. “By the end of the flight test campaign, Quarterhorse will be the fastest reusable aircraft in the world and the first of its kind to fly a TBCC engine.” The company will develop its Quarterhorse airframe in tandem with the U.S. Air Force Research Laboratory.
Detailed renderings of the Quarterhorse airframe, rough schematics, and other Hermeus designs can be seen here.
Hypersonic Flight
Hermeus calls itself a “venture-backed startup with the long-term vision of transforming the global human transportation network with Mach 5 aircraft” to speed up flight via their supersonic — Mach 5 or greater — airframe designs. So, for example, a 7-hour London to New York flight could be cut down to just 90 minutes.
Supersonic Airlines
It is not the first time that a company has drastically reduced flight times around the globe. For example, the joint Anglo-French Concorde supersonic passenger jet flew from the mid-1970s until 2003.
Although the Concorde fleet was significantly faster than its non-supersonic competitors, it was doomed by a combination of market forces and physics. A deadly crash in 2000 marred the Concorde’s reputation, and a dip in international travel after the 9/11 attacks reduced flight globally, but especially for the fast, luxurious — but expensive Concorde. In addition, while flying over populated areas, aviation authorities prohibited Concordes from flying supersonically because of the loud sonic boom the airframe caused by crossing the sound barrier.
Dual-Use Technology
Hypersonic passenger flight could revolutionize passenger aviation, though the technology is more often associated with a new class of missiles. Hermeus admitted as much in the company statement announcing the contract award.
“While this partnership with the U.S. Air Force underscores U.S. Department of Defense interest in hypersonic aircraft, when paired with Hermeus’ partnership with NASA announced in February 2021, it is clear that there are both commercial and defense applications for what we’re building” Hermeus CEO and co-founder, AJ Piplica stated.

Image Credit: Hermeus.
Postscript
“Hermeus is taking a different approach than traditional high-speed flight test programs. Hermeus will be leveraging autonomous and reusable systems, ruthlessly focused requirements, and a hardware-rich program. These three strategies allow the team to push the envelope, sometimes strategically to the point of failure in flight test,” the company explained. The challenges inherent to hypersonic passenger flight are not insignificant, but Hermeus believes they can overcome them.
Caleb Larson is a Defense Writer based in Europe. He holds a Master of Public Policy and covers U.S. and Russian security, European defense issues, and German politics and culture.
