Hypersonic aircraft developer Hermeus completed the ground testing of its Quarterhorse M1 demonstrator this week, paving the way toward first flight.

Conducted at Edwards Air Force Base in California, the ground-test campaign was completed in 21 days, encompassing integrated testing of vehicle subsystems, along with the software and hardware in the flight deck of the remotely piloted vehicle. This included checks of the redundant RF lines to ensure protection against potential electromagnetic interference issues.

In addition, Hermeus said it tested the human-machine interface to optimize pilot control. The campaign culminated in 130-knot taxi tests with full afterburner on a dry lakebed at Edwards, Hermeus said, adding this helped validate aerodynamic model assumptions and control surface performance. With ground testing complete, Hermeus is working toward obtaining U.S. Air Force and FAA approvals for flight.

"Hermeus is redefining the pace at which aircraft can be developed, tested, and fielded,” said A.J. Piplica, co-founder and CEO of Hermeus. “With Quarterhorse Mk 1, we’ve proven our ability to design and build a clean-sheet aircraft in just 204 days. Now, through this test campaign, we are demonstrating how rapidly and rigorously our team can validate the aircraft for flight—safely and comprehensively."

Quarterhorse was designed to provide insights into designs that would ultimately be used in a hypersonic civil and/or military aircraft.  The Mk 1 high-speed demonstrator will be used for takeoff and landing trials that will evaluate the effectiveness of control surfaces in flight performance and handling at high angles of attack, maneuverability under high-wing loading, and control gains and filters within the flight software.

Meanwhile, Hermeus has begun building the next iteration, Quarterhorse Mk 2, at its Atlanta facility.  Powered by the Pratt & Whitney F100, this aircraft will be capable of reaching supersonic speeds. These demonstrators will lead to the development of Darkhorse, a multi-mission hypersonic uncrewed aircraft designed for defense and national security missions, and ultimately, if all goes according to plan, the 20-passenger Mach 5 Halcyon aircraft.