Hypersonic AF1

An aerospace company called Hermeus on Thursday announced a contract with the U.S. Air Force and the Presidential and Executive Airlift Directorate to develop a hypersonic aircraft for the presidential fleet.

While the next Air Force One, a modified 747-8, is due to be delivered by Boeing next year, the Hermeus contract looks toward its eventual replacement.

Hermeus said it won the contract after designing, building, and successfully testing a prototype of an engine capable of propelling an airplane to Mach 5, or five times the speed of sound — about 3,300 mph. Mach 5 represents the delineation between supersonic and hypersonic speeds.

https://taskandpurpose.com/military-tech/air-force-one-hermeus

… Preceding the award, the Hermeus team designed from scratch, built, and successfully tested a Mach 5 engine prototype, in only 9 months. The test campaign both served as risk reduction for Hermeus' turbine-based combined cycle engine architecture and illustrates the team's ability to execute with schedule and funding efficiency. "Using our pre-cooler technology, we've taken an off-the-shelf gas turbine engine and operated it at flight speed conditions faster than the famed SR-71. In addition, we've pushed the ramjet mode to Mach 4-5 conditions, demonstrating full-range hypersonic air-breathing propulsion capability," said Glenn Case, Hermeus’ CTO.

https://www.hermeus.com/aug-06-2020

https://www.thedrive.com/the-war-zone/35456/air-force-eyes-hypersonic-vip-passenger-aircraft-in-new-deal-with-aviation-startup

https://www.thesun.co.uk/tech/12339878/us-air-force-invest-hypersonic-jet/