China’s first indigenous turbine-based combined cycle (TBCC) engine is undergoing endurance and reliability testing at a plant owned by the Aviation Industry Corp of China. The new engine is set to power the nation’s future hypersonic drones and could enable the People’s Liberation Army’s future stealth fighters to scale new heights.

AVIC’s Chengdu Aircraft Industrial Co revealed that the TBCC engine flight test project has been led by the same team of technicians tasked with the development of the J-20 and J-10 fighter jets.

The new TBCC powerplant combines a turbine and a ramjet engine to offer an ideal single-engine solution to achieving the shift from low speed to hypersonic speed. It will enable a plane to fly at speeds of up to Mach 6, six times the speed of sound, according to the Global Times.

Using turbine compression, turbojet engines can work at extremely low speeds and usually perform best up to Mach 2.2. Ramjets, using aerodynamic compression with subsonic combustion, are most efficient around Mach 3, and are able to reach Mach 6. A TBCC system combines the two power sources to use turbine power at low speeds and a ramjet engine at high speeds.

The TBCC engine is primarily designed for use in hypersonic cruise missiles and unmanned aircraft, including supersized reconnaissance drones and pilotless bombers. This is because no human can stand long periods of flying at such an extreme velocity, the newspaper cited an aerial expert as saying.

The newspaper also claimed that missiles propelled by a TBCC engine would be nearly impossible to intercept.

Though future Chinese fighters equipped with TBCC engines will be unlikely to reach the top speed of Mach 6, the state-of-the-art engines still promise an upper hand in dogfights, thanks to swifter acceleration and better maneuverability.

In recent years, US arms giant Lockheed Martin has been working on the development of the SR-72 using a TBCC propulsion system. The SR-72’s top speed will be Mach 6. Its first flight is expected in 2023, and it is scheduled to enter service by 2030, according to US defense website airforce-technology.com.

The SR-72 is the successor to the fastest aircraft the world has seen, the SR-71 Blackbird, a Cold War reconnaissance jet that the US Air Force retired in 1998. Although its top speed remains classified, industry experts widely claim that the SR-71 could reach Mach 3.2.

The SR-72 is envisioned with an air-breathing hypersonic propulsion system that has the ability to accelerate from standstill to Mach 6, or almost twice as fast as the SR-71.