plawolf, we can go ahead with the ad hominem attacks both ways if you don't want to be polite. You're being a nationalistic fanboy whose aim is play up the PLAAF's capabilities while downplaying contrary evidence.
Well you have made three mistakes just in this one paragraph alone.
Firstly, you took my criticism of your arguments as a personal slight when it I was just pointing out flaws in your reasoning or obvious omissions.
Secondly, you are trying to make personal attacks against me by making assumptions about me and what I believe in. There is a subtle but important difference between disagreeing with someone's opinion and disagreeing with someone personally.
Thirdly, your assumptions about me are completely baseless. Please point out exactly where in my last post I tried to play up the PLAAF's capabilities or downplay contrary evidence? And just FYI, pointing out you have no possible evidence to support your claims and opinions is not downplaying contrary evidence. What contrary evidence did you even present?
I can see from the rest of your post that you are trying to make reasonable arguments, which is why it is such a shame you had resorted to such a pointless and silly jibe.
Don't to so thin skinned by taking everything personally and trying to retaliate and just sticking to discussing the points will make your arguments a lot are more persuasive.
I've already mentioned the possibility of the F-35 having design errors,
So what design errors are those exactly? Another assumption without any evidence.
I tried to give the engineers and designers at LockMart (and SAC) a little more credit than that by not assuming there to be design errors unless I see actually factual proof of such errors.
but overall the additional space required for the lift fan is not a major issue; that space can easily be filled by fuel tanks. The F-35 spec is for particularly enlarged fuel tanks to enable extreme range without refueling; and if you note, the F-35B variant has significantly reduced fuel space and range compared to the F-35A or F-35B.
F-35A Fuel: 18,250 lb (8,280 kg)
F-35B Fuel: 13,500 lb (6,125 kg)
That would be a great counter if I was saying it was the lift fan itself that is to blame. Please read what I actually wrote because I even specifically pointed out that the A and C models will not have a lift fan.
Regarding your comments about weight gains during the transition from the X-35 to the F-35A, note that the F-35A in its final form has a minimum weight of 13,300 KG, or a gain of 13% empty weight. One thing to remember though, is that SAC does not do prototypes and besides that the weight listed at Zhuhai was not for a prototype, but for a ready export fighter.
So are you suggesting that LockMart planned for that 13% weight gain?
Humans aren't perfect and designs and prototypes are never ever flawless or perfect, especially with first prototypes. The whole reason new planes take years or even over a decade to test out before they can begin mass production is precisely because the first design for the plane always needs validating, and during that validation, issues invariably crop up that needs to be fixed.
The LockMart designers and engineers never planned to make their plane 13% heavier, they had to do it because issues cropped up and/or requirements changed that necessitated minor changes and redesigns.
The Chinese J20 certainly looks far more refined and closer to production standard than the X22 or X35 first prototypes, but it is still a prototype just the same, and it would be a first in aviation history if it did not need any tweaks or changes before going into production. I tend to avoid expecting things to be the exception and buck well established rules and I am seldom disappointed in that regard. Maybe you might want to consider adopting a similar policy.
As for the J31, the same applies really, in addition, we have only gotten medium quality photos of it so far, so it is another assumption to think that it will be as refined as the J20 prototype. Don't be fooled into thinking its at a more advanced stage than it actually is just because they painted the radome grey. It is almost certain that they don't have an actual radar under there.
My point is that at such an early stage, SAC is really only giving their best guess or reeling off design goals with range and typical weight figures for production aircraft because they simply cannot know what issues might crop up during testing and what fixes they might need to make, and that it is quite likely, even probable that the weight of the plane might creep up as they get nearer to the production standard.
If you had asked LockMart what their projected weight figures were for the production F35 was when the X35 first flew, I am pretty sure it would have been based on the design and actual weight of the X35, and as such, would have been considerably less than what the F35 weighs now.
You've also made a comment about allowances for weight given China's inferior engine technology. Unfortunately, in this case, weight reductions aren't free; compromises must be made one way or another. The F-35, for instance, is about 67% the loaded weight of the F-22, but in compensation it has given up a massive amount of wing area. If you consider the F-35C, which has a perfectly respectable wing area, it has an abysmal thrust to weight by most standards at the benefit of improving wing loading.
Did you somehow miss all the bits where I mentioned that the F35 and J31 are almost certain to be designed for different roles? It is an undeniable fact that strike aircraft are heavier than pure fighters.
The F15D has a minimum take-off weight of 12,970kg (the actual empty weight would be even less, but I think you get the point), whereas the F15E has an empty weight of 14,300kg. Both are twin seat with pretty much the same external dimensions so almost all the difference in weight is down to internal structure, which in turn was determined by their different designed roles.
If the J31 was also designed as a striker or the F35 designed only for AA, I would agree with you that it looks likely SAC had to make some design compromises to keep the weight down by so much. But when you consider that one plane is designed primarily as a striker while the other was designed as a fighter, that difference alone could by itself explain the difference in weight. Maybe SAC did have to make some design compromises, but there is no way that you or I can have any basis for saying that with what we know thus far.
We don't even know what the J31's empty weight is, and for all we know, we are comparing apples and oranges because we don't know what the equivalent loaded weight for the F35 would be.
The big issue is, you have an aircraft whose range is nominally higher than what is known about the F-35 (the F-35 uses 8000 kg of fuel to obtain this range!), is physically larger than what is known about the F-35 (length 16.9 wingspan 11.5 vs 15.7/10.7), yet is somehow lighter. Something's got to give, and I would say it's the weight figure.
Well what makes you think the typical take-off weight figure for the J31 corresponds with it's maximum range on internal fuel? Yet another assumption. For all we know, the J31 can hold more fuel (is is larger after all) than the F35. How much it might weigh when fully tanked up is another unknown though (thus you are likely comparing apples to oranges by using it's typical weight).
As you can see, most of your incredulity seem to stem from the assumptions you are making, assumptions that you cannot possibly have factual evidence to support. If we strip all those assumptions away, most of the things you find most vexing also becomes explainable or non-issues or unknowns. Which is kinda my main point. There is so much we don't know about the J31 that anything but the most basic conclusions seem premature and likely to be wrong, and I would say the same even if someone was claiming that the J31 was super-duper-awesome-source.
