Hermeus Marks Progress With Quarterhorse Taxi Testing
Hermeus, the Atlanta-based hypersonic aircraft developer, has completed low-speed taxi tests of its Quarterhorse Mk. 1 vehicle as part of the buildup to flight tests, which are planned to start later this year.
Hermeus, the Atlanta-based hypersonic aircraft developer, has completed low-speed taxi tests of its Quarterhorse Mk. 1 vehicle as part of the buildup to flight tests, which are planned to start later this year.
The Quarterhorse Mk.1 is intended to test and demonstrate the company’s ability to fly a high wing loaded vehicle with high takeoff and landing speeds and will pave the way for a series of larger, more capable Mk. 2 and Mk. 3 test vehicles designed for high Mach supersonic speeds.
“Quarterhorse Mk. 1 wrapped low-speed taxi testing this week,” says Hermeus CEO and co-founder A.J. Piplica. Commenting on social media, he adds: “Since completing the first full-throttle, max afterburner engine runs in late June, we’ve been knocking out test points as the vehicle continues to mature and our testing cadence accelerates. The melding of vehicle development with integrated testing is the magic that delivers fast airplanes—fast.”
Test points achieved so far include ground vibration, polarity checks, remote pilot functionality, nose wheel steering, closed-loop control surface actuation, communications link tests and straight-line taxiing. Other milestones noted by Piplica include side-to-side, or "slalom" taxiing, 90-deg. turns and taxi runs on the runway at the company’s DeKalb-Peachtree Airport base.
Upcoming work will include medium- and high-speed taxi tests, the latter phase at least of which is expected to be conducted on the longer runways and taxiways of Edwards AFB, California, where first flight and the follow-on test campaign will also take place.
The Mk. 1 vehicle is powered by a GE Aerospace J85-21, a 3,500-lb. dry thrust engine. The follow-on Mk. 2 will be powered by a 29,000 lb.-thrust afterburning Pratt & Whitney F100-229 with an integrated pre-cooler—the first element of the Hermeus-designed turbine-based combined cycle (TBCC) propulsion system. Further elements of the TBCC, including a ramjet, will be flown in the follow-on Mk. 3 version.
Hermeus says the Mk. 2 version will “be capable of hitting speeds greater than Mach 2.5,” while the Mk.3 with the full TBCC system “will reach speeds close to Mach 4 and pave the way for future Hermeus aircraft that will fly at hypersonic speeds.” This is scheduled to be the Darkhorse, a twin-engine design, which will target cruise capability at hypersonic speeds above Mach 5.