From Mach 0 to 6: this engine may power China’s future fighter jets and missiles

A graphic outlines the principle of the ramjet.

Photo: CCTV China is developing a revolutionary air-breathing engine for next-generation fighter jets and hypersonic missiles.

Designed to operate continuously from a stationary start-up to over Mach 6, the “contra-rotary ramjet engine” could replace the combined turbine-ramjet systems currently used in high-speed flight.

After more than three decades of work, the engine prototype has been completed and experimentally verified, marking a potential step towards engineering applications.

The next steps involve adapting the engine to various aircraft platforms and conducting real-world flight tests, according to researchers involved in the project. “China’s development of new-principle engines would be a strategic choice to break the Western monopoly and even surpass the West,” Xu Jianzhong, an academician of the Chinese Academy of Sciences (CAS), was quoted as saying in a China Science Daily report earlier this month.

Conventional approaches to hypersonic flight typically require two separate propulsion systems: a turbine engine for speeds below Mach 3 and a ramjet for higher speeds.

This configuration results in significant “deadweight” when one system is inactive and introduces technical challenges during mode transition due to differing airflow and combustion conditions, which can cause instability, particularly during climbing or manoeuvring flight.

The new design, developed by a team led by Xu, departs from conventional aero-engines by employing two sets of compressor blades rotating in opposite directions.

Conventional turbine engines are generally limited to speeds below about Mach 3 – modern fighters such as the F-22 and J-20 operate at roughly Mach 2 – while ramjets cannot function at low speeds or during take-off.

Xu’s contra-rotary ramjet aims to overcome these limitations by enabling operation across the full speed range without mode switching, a long-sought goal in aerospace propulsion, according to a 2025 report from a symposium held at CAS’ Institute of Engineering Thermophysics.

The concept of combining turbine and ramjet technologies dates to the end of the second world war, when German engineers developed turboramjet concepts.

However, those early designs used co-rotating turbine blades, which created significant material and stress challenges owing to compounded rotational forces.

The key innovation in Xu’s design lies in the contra-rotary compressor, in which high- and low-pressu

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