The world’s largest free piston wind tunnel. You’d never guess where it was built

According to a report published in South China Morning Post (SCMP)the Mianyang facility can simulate extreme flight conditions at 2.5-11.5 km/s, or more than 33 times the speed of sound.

We have built the world’s largest wind tunnel for a high enthalpy expansion tube.Dr. Liu Zhiguo of the Institute of High Speed ​​Aerodynamics

The tunnel is the heaviest piston ever

A tunnel with a diameter of about 80 cm will help, among other things, in preparation for a manned mission to the moon and work on a hypersonic aircraft (scramjet) that can go anywhere in the world within an hour. Due to piston reuse, wind tunnel operating costs are lower than other similar designs.

One problem is the piston itself at a Chinese facility, because it weighs 840 kg and is the heaviest ever in a wind tunnel. It must withstand compressed air pressure equal to 10,000 times the force of gravity. It is not easy, because it can travel at a speed of up to 540 km / h.

Read also: The Chinese have a new wind tunnel. It is so strong that it cannot be operated from the mains

Australian engineer Raymond Stoker proposed the concept of the piston-powered free-tunnel in the 1960s, which is why it was called the Stalker Tube. The United States and the Soviet Union built many wind tunnels during the Cold War. Its flight conditions were simulated using hot hydrogen, but since this gas is very expensive and difficult to store, it has become a problem in itself. The best solution is nitrogen under high pressure, which accounts for approximately 80% of the atmosphere – and this is exactly the solution suggested by Stoker.

The United States and Australia signed a cooperation agreement in 2020 to create a Mach 8 hypersonic aircraft that should leave Chinese and Russian solutions behind.