A Chinese physicist revealed that a new wind tunnel in Beijing will "soon" be unveiled that will put China decades ahead of the rest of the world when it comes to testing hypersonic weapons technology, according to a South China Morning Post report.
In an online lecture last week, Professor Han Guilai, of the Chinese Academy of Sciences, revealed new information about the JF-22 wind tunnel in Beijing, which will reportedly be capable of simulating flights at Mach 30.
The claim, however, has been disputed, with one expert saying reports "ignore the presence of a wide variety of decades-old facilities around the world."
Flying at Mach 30 is like 'swimming in mud'
The launch date for the JF-22 wind tunnel is currently classified. Still, during his lecture, Professor Guilai stated that it will be able to simulate flight at Mach 30, or 30 times the speed of sound and approximately 6.2 miles (10 km) per second.
During the lecture, Guilai said that the enhanced capabilities of this new wind tunnel, added to the existing research capacity of China's existing facilities, would put the country "about 20 to 30 years ahead" of the West. China's next most powerful wind tunnel is JF-12, which runs at a fifth of the power output of JF-22.
In his lecture, Guilai gave some insight into the conditions inside the soon-to-be-unveiled JF-22 wind tunnel in Beijing. "This air is no longer the air we breathe in," he said. "The flying vehicle we study is like swimming in mud." The physicist explained that the surface of an aircraft inside JF-22 at Mach 30 could reach temperatures of up to 10,000 degrees Celsius (18,032 Fahrenheit), which is hot enough to break air molecules into atoms and even give some of them an electrical charge. According to Guilai, the wind tunnel will have a power output of 15 gigawatts, which is roughly three-quarters the capacity of China's enormous Three Gorges Dam.
According to the South China Morning Post, China has had a great success rate in hypersonic flight tests in recent years because it uses chemical explosions to generate high-speed air flow instead of the mechanical compressors used in other countries. This allows for experiments within the wind tunnels to run for longer periods. "Our experiment time is much longer than theirs, so the aircraft model can be larger than theirs, and the experiments can be more advanced than theirs," Guilai said. "This determines our leading position in the world."
Aerodynamics expert hits back at 'false claim'
With only Professor Guilai's remarks to go on, and nothing in the way of official date announcements for the opening of JF-22, one U.S. scientist has strongly refuted the claim that JF-22 will put China decades ahead of the U.S. In a series of tweets, Dr. Chris Combs, an Assistant Professor in Aerodynamics at The University of Texas at San Antonio (UTSA), said the report by the South China Morning Post "ignores the presence of a wide variety of decades-old facilities around the world." He also highlighted the fact that he could not find an estimated completion date for the tunnel, but "even if it were finished tomorrow the claim would be false."
Hypersonic wind tunnels in the U.S. include the Hypersonic Tunnel Facility (HTF) at NASA's Neil A. Armstrong Test Facility in Sandusky, OH. That tunnel (pictured above), which was originally built to test nuclear thermal rocket nozzles, can test hypersonic flight up to Mach 7. The largest hypersonic blow down test facility in the U.S. is NASA's 8-Foot High-Temperature Tunnel (HTT), while CUBRC's LENS-II facility can test vehicles up to 30 feet in length.
In his thread, Combs also stated that you can only see Mach 30 speeds "during extraterrestrial return (Moon, Mars, etc.)", meaning that "until they start launching missiles from the Moon, this isn't even really military." He also highlighted problems with detonation-driven shock tunnels, stating that they "alter the air chemistry to the point that the aero will no longer be representative of flight."
Hypersonic aircraft such as the one in development by U.S.-based startup Hermeus promise to drastically cut down travel times. Hermeus has stated that it could enable flights between New York and London in as little as 90 minutes. The technology also has great potential for enhancing weapons capabilities. In April, a hypersonic weapon test by the U.S. Air Force ended in failure. By contrast, China sent a hypersonic missile into orbit in October using technologies that reportedly mystified U.S. officials.
Editor's note 22/12/21: The article was updated to present the views of Dr. Chris Combs, Assistant Professor in Aerodynamics at UTSA, on the claim made by Professor Han Guilai.