Hermeus is developing the Quarterhorse unmanned vehicle in partnership with the US Air Force as part of a $60 million project.
What’s interesting is that in designing a jet engine to go faster, parts are removed rather than added. In a turbo engine, air enters from the front and compresses the air, creating energy when the vanes rotate and burning when it comes in contact with the fuel. Blowing hot gases out the back of the engine causes the plane to move eastward. But at 3 times the speed of sound, there is no need to pressurize the air. As soon as the air enters the engine, it is already pressurizing itself when the speed is reduced. Ramjet engine types are called ramjets, from 3 times the speed of sound to 5 times the speed of sound. A ramjet engine has no moving parts like a turbojet. But the engine does not work below 3 times the speed of sound. The Hermeus company launched a supersonic plane. A turbojet engine will be used when landing. In flight, a ramjet engine will be used at 3 to 5 times the speed of sound. But the Hermeus company still has a lot of problems to solve, and because the fuel consumption is too high, we have to think about what kind of fuel to use in the long run. We also have to solve the problem of the fuel tank temperature being too high in supersonic aircraft.
The SR-71 Blackbird used a titanium fuel tank to cope with extreme temperatures. The Hermeus company also needs a lot of funding. But SpaceX’s Falcon 1 Dragon The Hermeus company said they will raise funds for the supersonic passenger plane project while building airplanes, just as they raised funds while building the Falcon Heavy and Starship rockets.