US supersonic aircraft developer Exosonic has started test flying a subscale demonstrator of a conceptual supersonic unmanned aircraft the company aims to develop for military customers.

The flight-test campaign comes after Exosonic, based in the Los Angeles suburb of Torrance, California, shifted its development efforts primarily toward military projects and away from a civilian supersonic jet that it had pitched several years ago.

The company has been performing test flights of its subscale supersonic demonstrator since last year but completed its first successful flight of the EX-3M Trident high-speed unmanned test aircraft in March.

“This test took place out on a dry lake bed in Southern California and reached a top speed of over 130kt [240km/h] at an altitude of roughly 600ft,” says Exosonic, which released a video showing the flight. “This represents a significant milestone in Exosonic’s company history as it proves that the company can translate its supersonic aircraft engineering design techniques into an airworthy aircraft.”

Exosonic came on the scene in 2019 with ambitions to develop a 70-passenger, Mach 1.8 civilian supersonic jet with 5,000nm (9,260km) of range, for mid-2030s service entry.

But it shifted its focus to military aircraft after landing several government contracts, including a 2021 US Air Force (USAF) deal to develop a supersonic unmanned aircraft for possible use as an adversarial fighter that would challenge USAF pilots. In March 2023, Exosonic won a USAF contract to design a supersonic aerial target for use in validating the performance of missiles.

The EX-3M Trident is a 20% subscale demonstrator of the company’s conceptual M1.4 Revenant unmanned aircraft, which Exosonic is pitching as both an adversarial air-training aircraft and as an aerial target.

Exosonic's conceptual UAV Revenant

Source: Exosonic

Exosonic says the EX-3M flight tests will inform development of a conceptual autonomous military jet called Revenant

“The main thing we are looking for is aerodynamic stability”, particularly low-speed stability, Exosonic co-founder and chief executive Norris Tie says of the EX-3M Trident flight tests. He adds that Exosonic is among a small group of supersonic- and hypersonic-aircraft developers that, with relatively minimal funding, have flown prototypes.

Manufactured over about nine months, the EX-3M Trident is about 2.4m (8ft) long, has a 1.5m wingspan and power from a small turbine engine. It is made primarily from composite materials, including 3D-printed parts.

Exosonic is using the initial flight tests to evaluate the stability of its design at slow speeds – a realm where ultra-fast aircraft tend to have stability issues, says Tie. The flight-test campaign falls outside Exosonic’s military contracts and is therefore funded not by the USAF but from the company’s internal research and development budget.

With the EX-3M Trident, “Exosonic went through several of the integration and flight-test challenges that would come from a larger aircraft programme”, the company says.

Exosonic says the demonstrator could also serve as a platform for use by governments and commercial players to validate manufacturing techniques and autonomy software and sensors.