China starts work on wind tunnel to test hypersonic aircraft
China is constructing the world's fastest wind tunnel, which will simulate hypersonic flight at speeds of up to 12km per second. At such a speed an aircraft could fly from China to the US in 14 minutes. The project is expected to be in operation by 2020 as China pushes forward its hypersonic weapon development programme. The US tested an unmanned hypersonic flight in 2011 but it lasted only minutes before crashing into the Pacific, while China recently conducted seven successful test flights. "China and the US have started a hypersonic race," said Professor Wu Dafang.

A J-10 jet fighter performs during the International Army Games on August 13, 2017 in Changchun, Jilin Province of China.

China is building the world's fastest wind tunnel to simulate hypersonic flight at speeds of up to 12 kilometres per second.

A hypersonic vehicle flying at this speed from China could reach the west coast of the United States in less than 14 minutes.

Zhao Wei, a senior scientist working on the project, said researchers aimed to have the facility up and running by around 2020 to meet the pressing demand of China's hypersonic weapon development programme.

"It will boost the engineering application of hypersonic technology, mostly in military sectors, by duplicating the environment of extreme hypersonic flights, so problems can be discovered and solved on the ground," said Zhao, a deputy director of the State Key Laboratory of High Temperature Gas Dynamics at the Chinese Academy of Sciences in Beijing.

The ground tests will significantly reduce the risk of failure when test flights of hypersonic aircraft start.

The world's most powerful wind tunnel at present is America's LENX-X facility in Buffalo, New York state, which operates at speeds of up to 10 kilometres per second – 30 times the speed of sound.

Hypersonic aircraft are defined as vehicles that travel of speeds of Mach 5, five times the speed of sound, or above.

The US military tested HTV-2, a Mach 20 unmanned aircraft in 2011 but the hypersonic flight lasted only a few minutes before the vehicle crashed in to the Pacific Ocean.

In March China conducted seven successful test flights of its hypersonic glider WU-14, also known as the DF-ZF, at speeds of between Mach 5 and Mach 10.

Other countries including Russia, India and Australia have also tested some early prototypes of the aircraft, which could be used to deliver missiles including nuclear weapons.

"China and the US have started a hypersonic race," said Wu Dafang, professor at the school of aeronautic science and engineering at Beihang University in Beijing who received a national technology award for the invention of a new heat shield used on hypersonic vehicles in 2013.

Wu has worked on the development of hypersonic cruise missiles, a near space vehicle, high-speed drones and other possible weapons for the People's Liberation Army.

He said there were a number of hypersonic wind tunnels in mainland China which had helped ensure the high success rate of its hypersonic weapon tests.

The new wind tunnel will be "one of the most powerful and advanced ground test facilities for hypersonic vehicles in the world", said Wu, who was not involved in the project.

"This is definitely good news for us. I look forward to its completion," he added.

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In the new tunnel there will be a test chamber with room for relatively large aircraft models with a wing span of almost three metres.

To generate an airflow at extremely high speeds, the researchers will detonate several tubes containing a mixture of oxygen, hydrogen and nitrogen gases for a series of explosions that could discharge one gigawatt of power within a split second, according to Zhao.

This is more than half of the total power generation capacity of the Daya Bay nuclear power plant in Guangdong.

The shock waves, channelled into the test chamber through a metallic tunnel, will envelope the prototype vehicle and increase the temperature over its body to 8,000 Kelvins, or 7,727 degrees Celsius, Zhao said.

That is nearly 50 per cent hotter than the surface of the Sun.