/VCG
In early 2026, Chinese researchers tested a prototype engine that, if mounted on an aircraft, would eliminate two of the biggest obstacles in hypersonic flight: dead weight and mode transition.
The engine – a "statorless counter-rotating ramjet" – is the work of Xu Jianzhong, an 85-year-old academic at the Chinese Academy of Sciences (CAS) who, with his team, has pursued this concept for more than two decades.
A ramjet engine is displayed in Chengdu City, Sichuan Province, China, January 20, 2025. /VCG
Turbofans operate from a standstill but top out around Mach 2.5, which is fast but not enough to be called hypersonic. Ramjets can reach Mach 5 and beyond, but they cannot start from zero. To give an aircraft both, engineers install two separate systems, one of which sits idle as dead weight while the other runs. The handoff between them is treacherous – airflow changes violently, the aircraft shudders, and the margin for error is razor-thin. America's X-51A flew four times, succeeding only once before the project was canceled.
The X-51A, pictured under the wing of a B-52 bomber, is set to demonstrate hypersonic flight. /US Air Force
Xu's team removed the stationary guide vanes – stators – that have been standard in jet engines for a century. In their place, they installed two sets of rotor blades spinning in opposite directions. At low speeds, the counter-rotating blades act as a supercharged fan. At high speeds, they create stable shock waves – abrupt pressure spikes that form at supersonic speeds.
The shock waves compress air far more efficiently than conventional designs. Two stages of blades, according to the CAS report, achieve compression equivalent to four to six conventional stages. The engine operates as a single system from standstill to hypersonic speeds, eliminating both dead weight and the dangerous mode transition.
Xu's approach attacks the problem through physics rather than exotic materials – a different path from the Western focus on heat-resistant alloys.
The prototype completed ground testing in March 2026. The CAS described it as having "completed experimental verification." The next phase is flight testing.
If the technology matures, it could power fighters, hypersonic missiles and space planes from a single engine that cold-starts on a runway without rocket boosters. It would be extraordinary.
However, while describing the tech as "potentially revolutionary," military commentator Zhang Zhaozhong noted a key challenge going forward: with the low-pressure fan section likely to create a speed ceiling around Mach 2.5 to 3, how will the team boost Mach speed?
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