The US Air Force has awarded Hermeus Corporation a $1.5 million contract to assess modifying the company’s in-development Mach 5 jet into an aircraft for the future Presidential and Executive Airlift fleet.
The US Presidential and Executive Airlift fleet currently includes the Boeing VC-25A, a modified 747-200B that is popularly known by its call sign “Air Force One” when the president of the USA flies aboard.
Hermeus – a company named for Hermes, the Greek god of transport, and the country of the US – was founded in 2018 and is developing an engine for a Mach 5 commercial passenger aircraft. The startup says it has successfully tested an engine prototype in a windtunnel simulating flight at M3.3 at 65,000ft.
That subscale prototype engine was built using an off-the-shelf turbojet used on various target drones and small personal aircraft. Hermeus declines to name the original engine or its thrust rating, but says it is capable of operating at around 533kt (988km/h) at maximum altitude of about 25,000ft.
The off-the-shelf engine is modified to power hypersonic flight, says AJ Piplica, chief executive and co-founder of Hermeus.
“We have a pre-cooler technology that we integrate to the to the front of the engine,” he says. “We have a ramjet that we put on the back end. And the ramjet is what we used to get all the way up to M5, once we get to the M3 range.”
The company is now working on a version of the engine that would be about 10 times the thrust of its subscale prototype, says Piplica. The startup is also designing an unmanned, autonomous demonstration aircraft to test the more powerful engine in flight. It anticipates the demonstrator aircraft first taking flight in two or three years. In mid- to late-2020 Hermeus plans to complete its ground development campaign of the full-scale engine.
Piplica declines to say if the USAF is aiming for a hypersonic Air Force One. Technically, any aircraft, whether it is the VC-25A or a smaller executive transport, such as the 737-based Boeing C-40 Clipper, is referred to as Air Force One when the US president flies aboard.
“They’re looking into what some of the next steps in their fleet might look like, towards the end of the decade and beyond,” Piplica says.