Why China’s First Stealth Fighter Was Rushed Into Service With Inferior Engines


Why China’s first stealth fighter was rushed into service with inferior engines

Problems encountered in development of new WS-15 engine mean PLA Air Force’s first J-20s are not so stealthy at supersonic speeds

PUBLISHED : Saturday, 10 February, 2018, 9:04pm

UPDATED : Saturday, 10 February, 2018, 11:32pm



Minnie Chan

Minnie Chan




China rushed its first advanced stealth fighter jet into service ahead of schedule last year, using stopgap engines, in the face of rising security challenges in the region, the South China Morning Post has learned.

But that means its capabilities will be severely limited, affecting its manoeuvrability and fuel efficiency as well as its stealthiness at supersonic speeds.

Without saying how many were in operation, the People’s Liberation Army Air Force confirmed on Friday that the J-20, the country’s fifth-generation fighter, had entered combat service, meaning it was combat-ready.

However, the aircraft was equipped with inferior engines designed for earlier warplanes when it first joined the air force in March last year because “critical problems” with its tailor-made WS-15 engine, exposed by an accident in 2015, had not been fixed, two independent military sources told the Post.

“The WS-15 engine designed for the J-20 exploded during a ground running test in 2015,” one source said, adding that no one was injured in the accident.

“The explosion indicated the WS-15 is not reliable, and so far there is no fundamental solution to overcome such a problem … that’s why the J-20 is using WS-10B engines now.”

The WS-10B is a modified version of the WS-10 Taihang engine, which was designed for the country’s fourth-generation J-10 and J-11 fighters.

The explosion was confirmed by another source close to the military, who said the reasons it happened were complicated, with one being the quality control of its single-crystal turbine blades, the key component for such a powerful turbofan engine.


The new-generation, single-crystal turbine blades designed for the WS-15 were supposed to be able to cope with the increased mechanical loads caused by significantly higher rotational speeds and extremely high temperatures.

Former Aviation Industry Corporation of China (AVIC) chairman Lin Zuoming told state media last year that China’s third-generation single-crystal turbine blades could withstand temperatures of up to 3,632 degrees Fahrenheit (2,000 degrees Celsius) in WS-10 engines, extending the engine’s lifespan from 800 hours to 1,500 hours when compared with those using the previous generation of turbine blade.

Japan deploys first F-35A stealth fighter, with mission to keep tabs on North Korea

However, the thrust-to-weight ratio of the original WS-10 engine was only 7.5, while that of the WS-10B tops out at about nine. The thrust-to-weight ratio of the all-direction, vector turbofan WS-15 Emei engine is more than 10 – one of the basic requirements for giving the J-20 “supercruise” ability.

Supercruise allows stealth fighters like the US’ F-22 Raptor to fly at supersonic speeds without using afterburners, making them harder to detect. The F-22 is powered by the world’s most advanced jet engine, the Pratt & Whitney F119.

But achieving supercruise would require the single-crystal turbine blades of the WS-15 engine to cope with temperatures even more extreme than those handled by the WS-10.


“Chinese technicians are able to produce cutting-edge-quality single-crystal turbine blades when concentrating on a specific single item,” the second military source said. “But they’ve still failed to turn the advanced technology into a standard product for mass production. It’s a bottleneck problem that needs more time to overcome after countless experiments and tests, based on Western experiences.”

“Using the WS-10B engines is just a temporary, expedient stage of the J-20’s engine development … in the future, the aircraft may use another new engine, the improved performance engine (IPE) version of the WS-10, the WS-10 IPE, until the development of the WS-15 is successful,” the first source said.

“It’s so embarrassing to change engines for such an important aircraft project several times … just because of the unreliability of the current WS-15 engines. It is the long-standing core problem among home-grown aircraft.”

Hackers use ‘China Chopper’ tool to steal Australia F-35 stealth fighter data from defence firm

It is at least the third time the J-20 has changed engines. The aircraft’s maiden flight was powered by two Russian AL-31 engines, which are less capable than China’s WS-10B.

Russia has refused to export its most advanced engines to China because they are the core technology of its aviation industry. That prompted China to develop an indigenous alternative, the WS-15, as part of its drive towards producing one of the world’s most advanced combat aircraft.

Beijing has stepped up the development of sophisticated jet engines since the turn of the century, with at least 150 billion yuan (US$23.7 billion) invested between 2010 and 2015, military insiders told the Post in 2016.

State-owned Aero Engine, a company formed in August 2016 through the merger of 24 AVIC subsidiaries with about 10,000 employees, has led China’s development and production of aircraft engines and gas turbines in recent years. One of the former AVIC subsidiaries, Shenyang Aeroengine Research Institute, developed the WS-10 and WS-15.


China Central Television boasted last year that the performance of the WS-15 had matched that of the F119, with a documentary aired in May claiming the WS-15 engines would be widely used in the J-20 by 2020.

That would make China the third country to have a fifth-generation fighter – after the US and Russia. Justin Bronk, a research fellow specialising in combat air power at the Royal United Services Institute, told Business Insider the design of the J-20 gave it “longer range, more internal fuel capacity, and larger internal weapons capability” than its US counterparts, the F-22 and F-35, and that meant it presented a real threat to US forces in the Pacific.

However, military analysts said it was too early for such prognostications because the underdeveloped WS-15 engine was not yet as sophisticated as the F119, which had a lifespan of more than 4,000 hours.

The prototype of Russia’s first fifth-generation fighter jet, the Su-57, took to the air for the first time in January 2010 but its maiden flight powered by the new Izdelie 30 engine, which was specially designed for it, only took place last month. The new engine will enable the Su-57 to achieve supercruise speed and fly consistently at 1,242mph (2,000km/h), but it still faces many tests, with the Russia Beyond website saying it would not be mounted on the Su-57 before 2019 or 2020.

China’s WS-15 project started in the 1990s, with the first prototype delivered in 2004 and the first successful ground-running test staged in 2015, Antony Wong Dong, a Macau-based military observer, said.

“China took 11 years to test the WS-15 after its prototype was created,” Wong said. “It’s very normal to take three to eight years for further development.

“And it’s still a significant achievement for China to develop the WS-10B as a stopgap for the J-20. China’s advanced aircraft engine technology foundation is very weak because its research and development started several decades later than its Western counterparts.”


America’s Pratt & Whitney and General Electric spent more than 12 years developing prototypes of the F119 engine in the 1980s, followed by another 14 years of testing after the engine’s maiden flight, fitted to an F-22, in September 1997.

The US also began developing the F-35, a single-seat, single-engine, all-weather stealth multirole fighter in the 1990s, with the first squadron – using Pratt & Whitney F135 engines, a derivative of the F119, joining its air force in 2016.

The US has started deploying F-35s at its military bases in the Asia-Pacific region, with 12 arriving at the Kadena Air Base in Japan in November. South Korea has said it plans to take delivery of 40 F-35s this year.

Earlier reports said Japan’s Maritime Self-Defence Force was also considering buying the F-35B “jump jet” version for its two new 25,000 tonne, flat-topped Izumo-class helicopter carriers. That pushed Beijing to put the J-20 into service as early as possible, military sources said.

Andrei Chang, editor-in-chief of Canadian-based Kanwa Asian Defence, said the J-20 might need at least eight years to improve its engine performance, but it was still the PLA Air Force’s most capable combat aircraft when it came to countering America’s F-22.

“The J-20 is more advanced than China’s fourth-generation fighters because of its stealthiness,” he wrote in the latest edition of the magazine, adding that it could also carry a greater quantity of more advanced air-to-air missiles.


Chang said he did not expect China to put the J-20 into mass production until the WS-15 project was wrapped up, but that training of J-20 pilots had been going on for a while. He said the PLA Air Force had deployed J-20s to the Dingxin Test and Training Base in Gansu province, where they and other warplanes had been used to study counter measures against the F-22 and F-35.

Hong Kong-based military commentator Liang Guoliang said there was a “very urgent” need for China to develop a carrier-based stealth fighter based on the J-20 because of the regional security environment was becoming more challenging.

“The US F-35B is much more powerful than China’s current carrier-based fighter, the J-15,” Liang said. “In case there is a war, the fighting capability of a Japanese Izumo helicopter carrier could come up to that of a Chinese aircraft carrier if each ship is equipped with five to six F-35Bs, with each one the equal of 10 J-15s.”

But, he cautioned, it would take at least a decade to turn a land-based fighter jet like the J-20 into a carrier-based aircraft because of the extensive modifications required, adding that the US had been developing carrier-based aircraft since the 1930s, while China had just started doing so this century.

China’s carrier-based J-15 is based on the Russian Su-33, a variant of the fourth-generation Su-27 fighter.

“China should hurry up; the central leadership should make a decision as soon as possible,” Liang said.


This article appeared in the South China Morning Post print edition as: stealth fighter rolled out with ‘inferior engine’



Hackers use ‘China Chopper’ tool to steal Australia F-35 stealth fighter data from defence firm

Information about the P-8, an advanced submarine hunter and surveillance aircraft, was also stolen

PUBLISHED : Thursday, 12 October, 2017, 11:29am

UPDATED : Thursday, 12 October, 2017, 8:46pm



Agence France-Presse

Agence France-Presse

Sensitive data about Australia’s F-35 stealth fighter and P-8 surveillance aircraft programmes were stolen when a defence subcontractor was hacked using a tool widely used by Chinese cyber criminals, officials said Thursday.

The 50-person aerospace engineering firm was compromised in July last year but the national cyber security agency, the Australian Signals Directorate (ASD), only became aware of the breach in November, technology website ZDNet Australia reported.

Some 30 gigabytes of “sensitive data” subjected to restricted access under the US government’s International Traffic in Arms Regulations rules were stolen, ASD’s Mitchell Clarke told a security conference Wednesday according to ZDNet.

Clarke, who worked on the case and did not name the subcontractor, said information about the F-35, the US’ latest generation of fighter jets, as well as the P-8, an advanced submarine hunter and surveillance craft, were lifted.

Another document was a wireframe diagram of one of the Australian navy’s new ships, where a viewer could “zoom in down to the captain’s chair”.


The hackers used a tool called “China Chopper” which according to security experts is widely used by Chinese actors, and had gained access via an internet-facing server, he said.

In other parts of the network, the subcontractor also used internet-facing services that still had their default passwords “admin” and “guest”.

Those brought in to assess the attack nicknamed the hacker Alf after a character on the popular Australian soap Home and Away, Clarke said. The three-month period where they were unaware of the breach they dubbed “Alf’s Mystery Happy Fun Time”.

Defence Industry Minister Christopher Pyne said “the information they have breached is commercial”.

“It is not classified and it is not dangerous in terms of the military,” he said.

Pyne added that Australia was increasingly a target for cyber criminals as it was undertaking a massive A$50 billion (US$39 billion) submarine project which he described as the world’s largest.

The nation has also committed to buy 72 F-35A aircraft for A$17 billion.

He would not comment who might be behind the breach, only stating that the government was spending billions of dollars on cyber security.

Western governments have long accused hackers in China of plundering industrial, corporate and military secrets.

The revelations came just days after Assistant Minister for Cyber Security Dan Tehan said there were 47,000 cyber incidents in the last 12 months, a 15 per cent jump from the previous year.

A key worry was 734 attacks that hit private sector national interest and critical infrastructure providers during the period, Tehan said.

Last year, the government’s Cyber Security Centre revealed that foreign spies installed malicious software on the Bureau of Meteorology’s system and stole an unknown number of documents.

This article appeared in the South China Morning Post print edition as: Australian F-35 fighter data stolen by hackers



Australian weather bureau hacked by foreign spies, report says

PUBLISHED : Wednesday, 12 October, 2016, 5:13pm

UPDATED : Wednesday, 12 October, 2016, 11:05pm


Agence France-Presse

Agence France-Presse


Foreign spies installed malicious software on an Australian government agency’s computer system, stealing an unknown number of documents, an official report revealed on Wednesday, stopping short of naming the country involved.

The security breach on the Bureau of Meteorology’s system, which has connections to the defence department, was detected in 2015 and initial media reports linked it to China.

China has previously been accused of hacking websites run by the US government and by private firms. In 2013 Chinese hackers were accused of stealing the top-secret blueprints of Australia’s new intelligence agency headquarters.

We don’t narrow it down to specific countries, and we do that deliberately


The government’s Australian Cyber Security Centre report released on Wednesday attributed “the primary compromise to a foreign intelligence service” but did not name any country as responsible.

“We don’t narrow it down to specific countries, and we do that deliberately,” said Dan Tehan, who assists Prime Minister Malcolm Turnbull on cybersecurity.

“But what we have indicated is that cyberespionage is alive and well,” he told the Australian Broadcasting Corporation.

The report said the national cyber security agency, Australian Signals Directorate (ASD), had identified the presence of Remote Access Tool (RAT) malware “popular with state-sponsored cyber adversaries” and other malware associated with cyber crime on the weather bureau’s system in 2015.

“The RAT had also been used to compromise other Australian government networks,” it said.

“ASD identified evidence of the adversary searching for and copying an unknown quantity of documents from the Bureau’s network. This information is likely to have been stolen by the adversary.”

The report also said while the threat of a cyberattack against Australia’s government, infrastructure and industry had grown in recent years, the risk from terrorist groups was low for now.

“Apart from demonstrating a savvy understanding of social media and exploiting the internet for propaganda purposes, terrorist cyber capabilities generally remain rudimentary and show few signs of improving significantly in the near future,” it said.

This article appeared in the South China Morning Post print edition as: Foreign spies hacked Australian weather agency

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