The engine can help the plane reach speeds of Mach 9

Engineers successfully tested a drone at subsonic speeds equipped with a rocket-like combustion engine, which can reach speeds of 11,000km/h when flying commercially in the future.

Venus Aerospace's drone in test flight with RDRE engine. (Video: Venus Aerospace).

Venus Aerospace Company completed a test flight of a drone equipped with a rotary rocket engine (RDRE) , helping the vehicle reach subsonic speeds. In the future, the company will build super-fast commercial jets using this new engine. During the test flight on February 24, Venus Aerospace flew the 2.4m long and 136kg drone to a height of 3,658m using the Aero L-29 Delfín aircraft before deploying equipment and activating RDRE, Live Science reported on April 10.

The drone flew 16km at a speed of Mach 0.9 (more than 1,111 km/h), using 80% of the RDRE's available thrust. The successful flight demonstrated the feasibility of rotary rocket engines and associated flight systems. Three weeks earlier, Venus Aerospace demonstrated the feasibility of this technology with a long-duration burn test, in which engineers showed that their engine could operate throughout the flight, an annular chamber with a diameter of about 25.4 cm and produces 544kg of thrust.

Rotational explosive rocket technology is 15% more efficient than conventional rocket engines, according to Venus Aerospace representatives. As a result, in theory, with the same amount of fuel, aircraft propelled by this technology can travel farther than conventional engines burning at constant pressure.

The drone flew 16km at a speed of Mach 0.9 (more than 1,111 km/h).

The successful test flight increases the odds of commercial feasibility of supersonic flight. One of Venus Aerospace's long-term goals is to develop a commercial supersonic aircraft that can travel at Mach 9 (11,000 km/h). For comparison, the Concorde aircraft can fly above Mach 2 (2,500 km/h) while the Lockheed SR-72 prototype is expected to fly at speeds above Mach 6 (7,400 km/h). A Mach 9 vehicle can fly from London to San Francisco in an hour.

Similar to the Concorde aircraft being very noisy when taking off, the steady detonation of the RDRE will cause the aircraft to emit extremely loud noise. Unlike jet engines, which typically accelerate more smoothly, repeated rapid acceleration cycles based on continuous detonation can place additional stress on the engine and associated support structures.

Because of RDRE's possible military applications, Venus Aerospace is collaborating with the Defense Advanced Research Projects Agency (DARPA). Now, the company plans more testing using drones. Engineers are considering installing the RDRE engine currently flying on larger drones that can reach speeds five times faster than sound (6,200km/h).