A drone with a ‘rotating detonation rocket engine’ approached the speed of sound
“The drone flew ten miles at Mach 0.9”
Venus Aerospace has completed the inaugural test ight of a drone
tted with its rotating detonation rocket engine (RDRE), accelerating it to just under the speed of sound. The company wants to one day build superfast commercial jets using this new type of engine. In a 24 February test ight, the company ew the drone, which is 2.4 metres long and weighs 136 kilograms, to an altitude of 3,658 metres with an Aero L-29 Delfín plane before it was deployed and the RDRE was activated. The drone ew ten miles at Mach 0.9 – over 680 miles per hour – using 80 per cent of the RDRE’S available thrust. The ight proved the viability of RDRE and the associated onboard ight systems. Three weeks earlier, Venus Aerospace demonstrated the viability of its RDRE technology with a long-duration test burn, during which engineers showed their engine worked for the duration of this test ight.
Rather than using a continuous burn like most rocket engines, RDRE operates by a detonation wave continuously rotating around an annulus, or ring-shaped chamber. The fuel,
hydrogen peroxide, is injected into the annulus, and the repeated detonations become self-sustaining after the initial ignition. In the RDRE test ight, the annulus was approximately 25.4 centimetres in diameter and produced 544 kilograms of thrust. The RDRE technology is 15 per cent more ecient than conventional rocket engines. As a result, an Rdre-propelled craft could theoretically travel farther on the same amount of fuel as conventional engines that combust fuel at constant pressure. Some have also theorised it could be as much as 25 per cent more ecient than current technologies.
The successful test ight raises the odds of commercially viable supersonic ight. One of the long-term goals for Venus Aerospace is to develop a commercial supersonic aircraft that could travel at Mach 9 – over 6,800 miles per hour. For comparison, the Concorde aircraft could y at just over Mach 2, or just under 1,550 miles per hour, while the forthcoming
Lockheed SR-72 prototype is expected to y at speeds greater than Mach 6, approximately 4,600 miles per hour. To put this into context, a vehicle ying at Mach 9 could travel from London to San Francisco in an hour. Just as Concorde was noisy at takeo, the RDRE’S constant detonations will make any craft tted with them incredibly loud. And unlike conventional jet engines, which oer much smoother accelerations, the rapid, repeated cycles of acceleration from the continuous detonations may also cause increased stress and fatigue of the engines and associated support structures.
Because RDRE could have military applications, Venus Aerospace is also collaborating with the Defense Advanced Research Projects Agency (DARPA). For now, Venus plans further test ights using drones. One test ight engineers are considering involves tting the current RDRE on a larger drone capable of achieving hypersonic ight
ve times faster than the speed of sound, approximately 3,900 miles per hour.