Chinese Engine Development

jobjed said:

Its OPR is overly ambitious for a country starting off weak in material science, at around 32 whereas the AL-31's is around 24.

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... also for a country with no experience in engine control systems for such a high-PR compressor!

jobjed said:

Another effect of the high turbine-inlet temp is the incorporation of large cooling channels in the WS-10's turbine blades. These channels bring up cool air to cushion the blades from the hot air of the combustion chamber but every litre of air used for cooling is a litre of air not optimally used to produce thrust. Therefore, most engine manufacturers try to minimise the amount of air passed through these channels to maximise efficiency.

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Yes, the AL-31F goes so far as to partially shut off the turbine cooling air bleed at lower thrust levels to improve fuel consumption (one of its innovative features).

jobjed said:

In the 1980s, 606 couldn't design components of an advanced engine independently so they copied the core of an American engine but adopted Russian design standards for the low-pressure compressor stage and afterburn section. This seems fine on the surface until you realise the Americans spin counterclockwise and the Russians spin clockwise.

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That sounds like a rather embarrassing blunder, as totoro says. Even if you accept the claim, counter-rotating LP/HP shafts had been done before (RR Pegasus earlier, and contemporary to the WS-10 the R-79, both to reduce gyroscopic effects in the hover). Recently (EJ200, F119, YF120, F135, probably M88 and Izd. 30) it has become near universal.

jobjed said:

This means a minimum bypass ratio of 0.84, the highest of its contemporaries, is what the WS-10 has to work with. This isn't ideal because high-altitude cruising is most efficient with a bypass ratio as close to 0 as possible.

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The problem isn't so much altitude but speed - the faster the aircraft flies, the higher the optimum exhaust jet velocity (which decreases with increasing BPR). Of course, the highest Mach numbers are achieved at altitude.

I am reading more into the counter rotating issue. The way I see it, it's being done lately on engines because it can make the engine more efficient. RR Pegasus was one of the first to do it, though F100 and similar generation of US engines did not use it. But newer engines seem to use it.

I somehow doubt such a feature would be by accident on WS-10. It makes more sense that it was done by choice, hoping it'd make the engine more efficient. However, if the material science isn't good enough, it's entirely plausible that the final result is not satisfactory, that certain engine parts wear out much more faster than western ones. Perhaps on a prototype it looked like a good idea and it seemed that the issue with materials would get solved over time, but the issues persisted and the engine design was frozen and stuck using that feature that may have proved to be too ahead of its time for the engine makers.

I don't doubt it was deliberate, but like you the way jobjed put the issue made it sound like a mistake to me.

With military engines, the idea is generally to reduce unwanted yaw motions due to gyroscopic effects, as I stated. This happens when the pilot makes pitch inputs at speeds where the tail surfaces have low effectiveness, so VTOL aircraft (Harrier & Yak-141), where the steady-state flight envelope extends right down to zero or even negative speed, were most affected. Hence their engines were the first to adopt counter-rotation, but from the 1980s on high-AoA post-stall manoeuvres gained prominence, so it became virtually ubiquitous in the following generation of fighter engines. For example, the procedure for a clean, straight-line exit from a Tail Slide in the Su-27 and MiG-29 calls for one throttle to be advanced faster than the other (I forget which side), to counter with asymmetric thrust the yaw caused by the gyroscopic effect of the engine rotating masses while the nose drops rapidly.

Some recent commercial engines later adopted the idea, to relieve aerodynamic loading on the NGVs at the interface between shafts which does give a fuel burn benefit. Curiously enough, RR looks likely to abandon counter-rotation again for their upcoming Advance & UltraFan architectures though. The YF120 is a special case, it pushed the aerodynamic load alleviation to the point that it could do away with the LP turbine NGV altogether, eliminating a heavy, expensive component that would also no longer require cooling air (counter-rotating statorless turbines).

Via qwerrty the on and off again China acquisition o Motor Sich now it is on again

Chinese to acquire stake in Ukraine's Motor Sich, sign helicopter deal with Russia | KyivPost
Published Feb. 26. Updated Feb. 26 at 5:44 pm
Days after the Russians and Chinese confirmed the signing of a contract for a joint venture to build next-generation helicopters, it has also been revealed that investors from China with strong ties to the Beijing government and armed forces have made progress with their plans to acquire a controlling stake in Ukrainian aerospace giant Motor Sich.

Despite there being an investigation into the attempted takeover by the Ukrainian State Security Service, or SBU, and a court ruling in April 2018 that froze funds and delayed the acquisition, a trade minister in Ukraine confirmed on Feb. 21 that the Chinese will acquire a stake in the company after all.

The Zaporizhia-based company is one of the world’s largest and most important manufacturers of helicopter engines and parts for civilian and military aircraft. Motor Sich is also considered, by many, to be strategically vital to the Ukrainian state.

Russian-Chinese helicopter deal

On Feb. 19, Russia’s state-owned defense manufacturing conglomerate Rostec announced that their deal with the Chinese, years in the making, would be inked before the end of April.

“We have prepared and will sign in the coming two months a contract of the century with China on the joint development, production and sales of a new generation heavy-lift helicopter. We have spent four years in intense talks on this project,” Rostec’s Viktor Kladov said, quoted by Russian state media.

The Chinese acquisition of a stake in Motor Sich, and the vital technology it will acquire, could be important to its joint project with Russia.

According to Rostec, the new Russian-Chinese helicopter will be powered by turboshaft engines that are based on one developed by the Ukrainian companies Motor Sich and Ivchenko-Progress. The Russians and Chinese will also develop new engines for their helicopter.

Previously, some Chinese aviation analysts heaped praise on Motor Sich hardware and suggested that China should prioritize the acquisition of more Motor Sich engines for the Chinese military. They also boasted, in Chinese-language media, about how the Motor Sich engines can be modified and reverse-engineered to better fit the PLA’s needs.

Together, China and Russia say they will build a new cargo and troop-carrying helicopter that they claim will be more powerful than the American equivalent and perfected for round-the-clock operations in hot climates, difficult weather conditions and highland areas.

Experts have said that the Chinese want up to 200 of the new helicopters before 2040. It’s not immediately clear how many the Russians want.

Chinese want Motor Sich

In order to bring its armed forces up to scratch, China has looked abroad, with an increasing amount of its focus on getting its hands on Ukrainian military technology.

China has said it wants to buy and build the Ukrainian Antonov An-225s – the world’s largest cargo plane. It reportedly had a contract with Antonov to ship plane parts to state-owned factories in Chengdu and Shaanxi for assembly, but the current status of that deal is no longer clear.

In 1998, the Varyag, an unfinished aircraft carrier that was started during the Soviet era, was sold by Ukraine to Chinese businesspeople to be used as a floating hotel and casino. Today it’s China’s first aircraft carrier: the Liaoning.

These days, China is eyeing Motor Sich so that it, in partnership with Russia on some projects, can build a fleet of modern, next-generation helicopters.

The Chinese company that has been courting Motor Sich, Beijing Skyrizon Aviation, is believed by some to be a proxy for the PLA’s strategic, aerospace acquisitions and is at least partly state-owned.

But it’s also at least partly-owned by the mysterious Chinese businessman Wang Jing, who has alleged ties to China’s ruling communist party as well as Russia. In 2013, before the Russian invasion of Crimea, Wang Jing touted plans to build a deep-water port near the Russian naval base at Sevastopol, although not much seems to have happened on the project since.

Since 2015, Beijing Skyrizon Aviation has been sending hundreds of its specialists to different aerospace companies and technology institutes in Ukraine, especially ones in Kharkiv and Zaporizhia. In September 2017, they made their move to acquire a majority stake in Motor Sich.

Motor Sich’s owners have told reporters that only 15 percent of the company was being sold to the Chinese investors for $100 million, although court documents cited at the time have shown that Beijing Skyrizon had allegedly used a shell company in the British Virgin Islands to purchase a 56 percent stake for $100 million.

In late April 2018, amid an outcry from pro-NATO lawmakers in Ukraine, the SBU launched an investigation, called the Chinese takeover attempt an “enemy sabotage plot,” and requested that the courts halt the takeover and freeze the funds, which they did.

In May 2018, after the courts had intervened, meetings were held in Kyiv between the Chinese Ambassador to Ukraine, Du Wei, Deputy Prime Minister Stepan Kubiv and Deputy Minister of Economic Development and Trade Yuriy Brovchenko, according to Interfax news. Company executives from Beijing Skyrizon Aviation also attended those meetings.

According to Brovchenko, who spoke to the Interfax news agency after the meetings, the purpose was to present China’s position and begin finding a solution to the impasse.

“At the meeting, the parties voiced full mutual understanding of the processes that are taking place today in China and Ukraine, including the situation around PJSC Motor Sich, and expressed mutual interest in a prompt settlement, taking into account the bilateral interest in cooperation,” Brovchenko said at the time.

“I think that in the near future the situation around Motor Sich will be resolved, including taking into account the interests of Ukrainian-Chinese cooperation in the aviation industry,” Brovchenko added.

But in October 2018 the case was still tied up in the Ukrainian courts, according to Ukraine’s highest-ranking security official.

“We stopped this takeover on the grounds of national security,” said Vasyl Hrytsak, the head of the SBU, in a short comment to the Kyiv Post on Oct. 8 at a security conference in London. “It’s in the hands of the courts now,” he added at the time.

(cont)
No comment on new deal

Behind the scenes, and despite the concerns of many Ukrainians and similarly-minded allies, some Kyiv lawmakers and the Chinese appear to have reached a quiet compromise.

On Feb. 21, Deputy Minister Brovchenko, who took part in the May 2018 talks with Kubiv, Ambassador Du Wei and officials from Beijing Skyrizon Aviation, announced that the Motor Sich deal, or some variation of it, was still going ahead.

In an interview with the Delo.ua website the deputy minister, when asked about the blocked Chinese attempt to buy a 56 percent stake in Motor Sich, suggested that the situation was being resolved and the investors from Beijing would still be brought on board.

“Chinese investors will have a certain stake,” he said, not elaborating on what the size of the stake would now be, or if it had already been confirmed. Brovchenko added that the state would work with the Chinese, who would have an important role in taking the company forward, “namely, in the development of aircraft construction and the production of helicopters,” he added.

He also said the state could take on a role, alongside the Chinese, in running Motor Sich. “I think that work is under way on the possible participation of the state in the operation of Motor Sich,” he said.

On Feb. 26, Motor Sich declined to comment or give an interview to the Kyiv Post. A secretary for the company’s public relations director refused to transfer any calls, instead requesting written questions that she said may or may not be responded to, as they pertained to stock transfers or acquisitions.

An employee in the company director’s office would not give her name and told the Kyiv Post “I am not going to tell you anything.”

The Kyiv Post has emailed questions to Motor Sich and requested an interview. Multiple, previous emailed requests for comment and attempts to arrange an interview have been unsuccessful.

The Chinese Embassy in Kyiv had not responded to an emailed request for comment by the time this story was published. Beijing Skyrizon Aviation could not be reached for comment.

Allies worry about China

China and Russia have a deepening, strategic relationship. China is Russia’s number one trade partner, with bilateral trade reaching an all-time high this January: more than $100 billion in that month alone.

Last year, Russian President Putin and Chinese Premier Xi Jinping formalized what is effectively a military alliance and pledged to greatly improve their cooperation on the international stage. They also agreed to at least $1 billion in new, joint investments abroad, affirming they would together face challenges of “strategic stability” together.

Some of Ukraine’s Western and Asian allies are very concerned with Chinese moves on Ukrainian aerospace. They have been vocal in their opposition, but it’s not yet clear if the Ukrainians are listening.

The Americans and the Japanese are especially worried about more Ukrainian aerospace technology falling into Chinese hands.

Last summer, as reported by the Kyiv Post, senior Pentagon officials were in the Ukrainian capital to deliver a warning to Ukraine that China wants to reverse-engineer and produce Ukrainian hardware on a large-scale.

Hanna Hopko, a member of parliament and the head of Ukraine’s Committee on Foreign Affairs, has also been outspoken about the potential deal, saying it’s damaging to Ukraine and its NATO allies.

“It’s extraordinary that we would allow a strategic partner of Moscow to acquire such sensitive and unique technology,” she said in June 2018.

Japan is also paying attention to Ukrainian-Chinese relations, especially if it could benefit the regional ambitions of the People’s Liberation Army.

Masaru Tanaka, an expert from the Bank of Japan who now advises the Ukrainian government through the Japan International Cooperation Agency, or JICA, said Japan has serious concerns over Chinese interest in Ukrainian aerospace technology. If the Chinese takeover of Motor Sich is to be pushed forward, despite the Ukrainian courts temporarily halting it, it must be stopped, Tanaka said in Oct. 2018.

“Chinese entities are acquiring and buying sensitive technology from Ukraine that threatens Japan,” he told the Kyiv Post. “We must stop the deal… the G7 must stop the deal.”

Additional reporting by Igor Kossov.

Well, I think at least long term there is no reason not to unify development with Russia. Not only would development costs and time be cut, but compatibility between allies is highly useful. A joint project could be a great improvement, provided that R&D dialogue works well.

Long term I also believe Russia will adopt more PLA style network centric/force multiplier tactics as opposed to Soviet style mass assault tactics.

Variable-cycle engine for China's next-generation fighter program?



The above photo is of a 7-page article published by the journal "Technology Reward" (科技奖励) in November of 2018 that contains an interview with Mr. Liu Yongquan (刘永泉), who is the chief designer at Shenyang Engine Design Institute. Unfortunately, I do not have access to the article. However, from , I gleaned this tidbit:

近日，据《科技奖励》权威媒体发表的文章：航空动力的攻“心”战——记航空发动机集团专职型号总师、沈阳发动机研究所总设计师刘永泉一文中披露，我国在自适应变循环航空发动机取得了重大了突破，已完成变循环特有的关键技术整机验证，构建了自适应发动机关键技术体系，让人振奋不已

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Translation: China has made good progress on a variable-cycle engine, having achieved systematic verifications on key variable-cycle technologies (已完成变循环特有的关键技术整机验证) and established critical technology systems for adaptive engines (构建了自适应发动机关键技术体系).

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Please help with the translation, as I'm not sure about how to translate the green part of the text.

by78 said:

Variable-cycle engine for China's next-generation fighter program?

The above photo is of a 7-page article published by the journal "Technology Reward" (科技奖励) in November of 2018 that contains an interview with Mr. Liu Yongquan (刘永泉), who is the chief designer at Shenyang Engine Design Institute. Unfortunately, I do not have access to the article. However, from

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, I gleaned this tidbit:


Please help with the translation, as I'm not sure about how to translate the green part of the text.

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"自适应发动机" is the short hand for "自适应变循环航空发动机", adaptive variable cycle aircraft engine. It should be a variable cycle engine like the one in Adaptive Versatile Engine Technology program. The verb of the clause is "构建了" (has established) and the object is "关键技术体系" (a system of key technologies). "自适应发动机" modifies the extant of the object. And we have:

[China has] established a system of key variable cycle engine technologies.

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Oh dear. Get ready for ADVENT copying accusations in a few years. It'll almost be like the Americans figure some solutions out and immediately upload their solutions online for the Chinese to implement. Honestly if anyone has alien spacecraft wreckage, they should just hand it over to China and we'll all be zooming around in anti-gravity cars a few years later

ougoah said:

Oh dear. Get ready for ADVENT copying accusations in a few years. It'll almost be like the Americans figure some solutions out and immediately upload their solutions online for the Chinese to implement. Honestly if anyone has alien spacecraft wreckage, they should just hand it over to China and we'll all be zooming around in anti-gravity cars a few years later

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the understanding of your typical military enthusiast for what reverse engineering actually requires is rather cringeworthy.

People often conflate "innovation" with having "imagination" rather than having mastery of the preceding technologies that is required for one to push the leading edge of technology. Reverse engineering still requires understanding of the processes and technology necessary to build a product.