True China builds lots of products, many of them of really shoddy quality, you forget the Russia has built and exported hundreds of Su-27s, that the Su-27 family has different generations, a Su-27 built in 1986 is not the same built in 2016.
Chinese quality may be shoddy, but it is still better than Russian quality. That's one of the reason why the Su-27 deal was terminated early.
Our Chinese colleges here are saying China does not need the Su-35, but let us go J-11 is not a Chinese product but a Russian license of Su-27 with some enhancements, but Russia has not been idle, the Chinese claimed they improved the Al-31 service life, but in that same period Russia built the Al-31F-M2/3 variants, which are much better than any Chinese improvement, in fact they boast about WS-10 but still 117S is a much more modern engine and China still buys Al-31s.
Many Chinese programs have Ukrainian Russian finger prints, Y-20 for example has direct Antonov, Assistance, same ARJ-21, L-15 and many Chinese programs.
So i will put it simple, 117S gives to China two advantages longer range and higher speed on Flanker platforms.
The same old attempt at trying to claim somebody else's effort as Russian's.
The Al-31F was designed and perfected by the Soviets, and Ukraine played a major role. The Al-31F derivatives including 117S are Russian modifications based on Soviet technologies. Were China to have access to the same technical documentation that Russia inherited, China could do the samething, just as China is doing now with imported Ukraine engines.
As a derivative of the Al-31F, the 117S is still an engine for fourth generation aircraft. The 117S is still in the same class as WS-10 no matter how you inflate the thrust figure. Not even Russia has F-119 class engine in production. So Russia and China are at equal footing in engine technologies.
The difference between China with WS-10 and Russia with Al-31F is that China ran through the whole design cycle of a modern turbofan engine and brought the WS-10 to maturity. Russia has no such experience aside from basking in Soviet's glory.
The Su-35 is a great enhancement to the J-11 fleet, here our colleges minimize the fact Su-35 supercruises, but basically it means less fuel spent so it means longer range add Su-35 carries more fuel internally, (which means new internal structures and enhanced avionics) means Su-35 enhances power projection over any J-11.
Even J-20 with inferior engines can not compete, regardless you say it is stealthy, J-20 has not better engines, it is almost as large as a Su-35 and at least as heavy, so it has no better range.
Su-35 is based on the same aerodynamics as Su-27. An airframe which isn't designed for supercruise in the first place isn't optimized for supercruise. A slight increase in engine thrust isn't going to compensate for exponential increase in air drag.
Russia's own boasting of Su-35 supercruise capability only claimed the aircraft can still manage to accelerate after passing the speed-of-sound. The claim stops short of mentioning the top supercruise speed and never mentions combat load. It is not a true supercruise capability that F-22 has.
Russia is not about charity, China pays or no deal, Russia needs money, and Su-35 is a very advanced weapon, is 5th generation subsystems on a 4th generation fuselage, J-20 is a 5th generation fuselage but lacks the most important 5th generation thing, without it, no supercruise, no STOL, no super maneuverability, and no post stall regardless of what you say without TVC nozzles there is no credible post stall handling, so in few words the Su-35 is a gift Russia is not willing to sell without the most money they can get, Russia knows China eventually will get the technology embedded in 117S, but for them they will make sure they take more time and they get the most money, so China and Russia are negotiating and for that reason it has taken long
Post-stall maneuverability is tactically useless. The major reason why Russia still promotes it is because Russia has nothing else to promote, not that post-stall maneuverability is any good.
