X-51 WaveRider hypersonic jet
An artist's illustration of the X-51 WaveRider being tested by Nasa and the US Air Force. Have the Chinese secretly beaten the US with a successful test flight and landing of a hypersonic jet? Who knows, as the news has been pulled from the internet US Air Force

An article claiming that China succeeded in achieving hypersonic flight at Mach 5 has been mysteriously pulled off the internet a few days after it went live.

On 18 September, state-run trade magazine China Aviation News, which focuses on the international aerospace industry, published an English language article about a night-time test flight of an experimental aircraft that took off, reached speeds of Mach 5, and then safely landed on the airfield.

Hypersonic aircraft are currently more of a concept than reality, and are generally defined as those travelling above 3,840mph - five times the speed of sound (Mach 5). Until now, no nation has claimed to have successfully launched, flown, and landed such an aircraft.

Why was such an amazing breakthrough quickly silenced?

According to The Daily Beast, the article spoke of a dark-painted aircraft that disappeared in the sky, much to the excitement of the test team watching from the ground. "A few hours after take-off, the task is complete," reporter Qi Shengjun wrote, adding a literary flourish as he compared the test plane's landing to the sheathing of a sword.

"When the 'aircraft brake' instruction is issued, this mission comes to a successful conclusion. The original anxiety and tension is instantly released—applause, laughter sounding in the control room."

Apart from China Aviation News, the article was also reported by a Hong Kong newspaper called Ta Kung Pao, so it seems that a test flight did indeed occur.

Interestingly, Want China Times reported that Chinese state-owned aerospace and defence manufacturer Aviation Industry Corporation of China (AVIC) released a report on 18 September about something similar.

The report claimed that AVIC had completed an initial test flight of an unspecified high altitude, super-fast aircraft that had a "unique flying style", but the report was also deleted by the time that the Want China Times article went live on 21 September.

Usually China is very happy to celebrate its technological triumphs over the West, but September marked a significant occasion – Chinese President Xi Jinping's first official visit to the US. Still, the reason isn't clear as to why China wouldn't want the world to know that it succeeded in flying and landing an aircraft achieving speeds of Mach 5 – a feat that has been beyond the reach of scientists and aerospace engineers.

The complex problems with hypersonic aircraft

In order to achieve such speeds – beyond twice that of the Concorde – engineers have been developing supersonic combustion ramjet engine (Scramjet) technology since the 1950s, by changing the way planes function and making them lighter.

Rockets work by combining a liquid fuel with liquid oxygen in order to create thrust, and carrying both fuel and oxygen tanks on board the aircraft adds weight and slows it down.

To lighten the load, scientists have long theorised about an aircraft engine in which the oxygen needed to create combustion is taken from the atmosphere around and passing through the vehicle as it flies, rather than having a tank on board.

However, many test flights for hypersonic aircraft conducted by the US Air Force, Nasa, and scientists in Russia and China have failed completely or shown promise and then crashed. Hypersonic flight technology has been considered more of a pipe dream, that perhaps could lead to increased missile speeds if testing ever does yield results.

The most recent test flight of hypersonic aircraft hailed as a success by the US Air Force was conducted in May 2013 by Nasa. During that test flight, the X-51 Waverider was launched off a B-52 bomber already in flight. It accelerated to Mach 5.1 while ascending to 60,000ft, flying for 210 seconds before running out of fuel and crashing into the Pacific Ocean.

Who will win the hypersonic race?

In April, Airbus received a patent for a hypersonic jet that will supposedly be able to travel from London to New York in four hours. to be in service by 2023. The German space agency announced in September that it is developing a hypersonic rocket jet transportation vehicle that could travel from Australia to Europe in just 90 minutes, to be ready by 2045.

Even the US Air Force broke its silence in July to announce a partnership with the Pentagon to speed up development of hypersonic aircraft that could cross the globe in four hours by 2023. But all these projects are merely pipe dreams for now, so it will be interesting to see who succeeds first, especially since aerospace analysts don't think China has any hope of coming out on top.

"Hypersonic has been likened to lighting a candle in a hurricane. It's that tough. We've been tantalisingly close but still many decades away," Richard Aboulafia, an analyst at aerospace and defence industry advisory firm Teal Group, told IBTimes UK in July.

"Hypersonic is intriguing but the technological breakthroughs needed are enormous. I don't think you'll see much progress with the Chinese and Russians. If it happens, it will happen in the US."