American startup Hermeus, which aims to build the world's first hypersonic airliner, has unveiled a full-scale prototype of a Quarterhorse aircraft.

During the presentation, the engine was fired at full afterburner, giving credence to Hermeus’ claim that the aircraft is “much more than just a showpiece”. 

“We designed, manufactured, and integrated the aircraft from nothing but an outer shape, in four months,” Skyler Shuford, COO of Hermeus, said in a press release.

The company, which admitted that the Qarterhorse prototype is static, did not elaborate on what it will be used for. However, judging from its size, it is most likely an unmanned technology demonstrator.

Eventually, the company intends to build a hypersonic airliner, and has signed a contract with the United States Air Force (USAF) to develop an executive aircraft that can be used as the Air Force One, the aircraft used to carry the president of the United States.

Read more: Hermeus partners with USAF to develop supersonic Air Force One

Hermeus says its aircraft will cruise faster than Mach 5, or five times the speed of sound. Normal jet engines cannot reach such speeds, necessitating the development of a new kind of engine, such as a ramjet or a scramjet. However, ramjets and scramjets do not function at low speeds. So, a hypersonic aircraft must employ either a combination of engines, or a hybrid engine with various modes of operation for different speeds. 

According to Hermeus, the aircraft will use a turbine-based combined cycle engine, which has different sections to process air at different speeds.

A low-speed section of the Hermeus’ engine is based on a General Electric J85 turbojet, which is used on numerous small aircraft, including the Northrop F-5 fighter jet and a T-38 Talon trainer. A high-speed section, which would be engaged as soon as the aircraft reaches Mach 3, is a ramjet.

The company revealed that early tests have already been conducted on prototype engines 

Hermeus has not yet revealed when it plans to reveal a flyable prototype or conduct a test flight.