Hypersonic scramjet projectile flies
30 August 2001
The first-ever successful free flight of a hypersonic projectile powered by a supersonic combustion ramjet (scramjet) engine burning hydrocarbon fuel took place last month, according to the US' Defense Advanced Research Projects Agency (DARPA). The projectile is a four-inch diameter, 20-percent scale model of a conceptual missile.
On July 26, GASL Inc fired the scramjet projectile out of a large gun at the US Air Force's Arnold Engineering Development Centre in Tennessee. The test is an important step towards the realisation of flight at hypersonic speeds.
The test was the second of two successful launches, the first occurring on June 20. Together, these tests demonstrate that scramjet engines will provide enough thrust to power a free-flying vehicle.
The tests used Arnold's two-stage light gas gun to accelerate the projectile to the flight condition through a 130-foot long gun barrel. The projectile experienced peak acceleration of approximately 10,000 Gs, and was launched from the gun at Mach 7.1.
Arnold's G-Range facility is the only range in the country capable of providing the low-acceleration loads required to launch the projectile. After the titanium projectile was launched, it used its scramjet engine to cover a distance of 260 feet in slightly over 30 milliseconds.
Scramjet engines provide propulsion at speeds above Mach 5 by capturing atmospheric air to burn on-board fuel. These air-breathing engines are more efficient than rocket motors for hypersonic propulsion, and will ultimately allow the possibility of longer duration flight with greater payload.
Applications for such engines include powering long-range hypersonic missiles, gun-launched kinetic energy weapons, and access to space vehicles. In order to operate, scramjet engines must first be travelling at hypersonic speed. An accepted approach to reach scramjet take-over speeds is to attach the scramjet to a rocket booster as a first stage and then operate the scramjet once the rocket has increased the speed sufficiently.
Additional launches are planned, with higher performance scramjet engines and longer flight durations. GASL is performing the tests under a Phase II Small Business Innovation Research contract with DARPA.
REF XQQAS XQQAR XQQLD XQQTY
In knowledge we trust!