Chinese Academy of Sciences Unveils Prototype "Contra-Rotary Ramjet" Engine Capable of Sustained Hypersonic Flight Above Mach 6

China's CAS completes prototype of a "contra-rotary ramjet" capable of Mach 6, eliminating the need for separate turbine and ramjet systems.

By: AXL Media

Published: Apr 2, 2026, 3:54 AM EDT

Source: Information for this report was sourced from Interesting Engineering

Breaking the "Dual-System" Propulsion Barrier

Hypersonic flight has traditionally been hindered by the necessity of dual propulsion: a conventional turbine for takeoff and acceleration to Mach 3, and a ramjet or scramjet to take over for speeds exceeding Mach 5. This "mode-switching" is notoriously complex, adding significant "deadweight" and operational risks during high-speed maneuvers. However, a breakthrough from the Chinese Academy of Sciences (CAS) suggests a new path forward. Researchers have unveiled a "contra-rotary ramjet" engine designed to run continuously across the entire flight envelope, from a stationary start to above Mach 6, effectively merging turbine and ramjet technologies into a single, cohesive unit.

The Innovation of Contra-Rotary Architecture

The core of the system lies in its unique compressor design, featuring two sets of blades rotating in opposite directions. This contra-rotary approach allows the engine to maintain high relative speeds for compression while reducing absolute rotational speed. According to lead researcher Dr. Xu Jianzhong, this architecture significantly lowers the centrifugal forces acting on the blades and discs, enhancing structural integrity at extreme speeds. By removing the need for guide vanes between high- and low-pressure stages, the team has created a more compact engine where two stages of vanes provide a boost capacity equivalent to four or six stages in a traditional configuration.

Harnessing Shock Waves for Compression

In a departure from conventional aeronautical engineering, which often seeks to minimize shock waves, the CAS prototype actively harnesses them. The engine uses shock waves to assist in airflow compression, a strategy that simplifies the internal geometry and reduces the overall weight and size of the unit. This "ram-compressor" concept, which the team has been refining since 2000, allows for a more streamlined transition to hypersonic velocities. The result is an engine that is not only lighter but potentially more reliable, as it avoids the aerodynamic instabilities typically associated with switching between different propulsion modes during climbing or high-G maneuvers.