Yep, and you're one of mine as well,,, I am going to agree with Trident! that's a whopper!
J-20 - physical parameters and other overflow from main thread
- Thread starter latenlazy
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Yep, and you're one of mine as well,,, I am going to agree with Trident! that's a whopper!
It's no doubt lighter than an F-35 at the present bro, whether or not it will ever progress beyond the proof of concept stage will determine whether or not it gains weight?? As of now, there are no gun, no avionics of note, and likely no radar, nor coatings?? so it is light? no doubt 2001 and 2002/2004 were light as well, but now that the J-20 is going to have to go to work for a living, and real 5 Gen equipment, those days are over.
Equation
Lieutenant General
2 x RD-93 = 2,100kg; F-135 = 1,700kg
The claim was never that J-20 is 15 tons on the dime. The claim was that J-20 was "controlled to the 15 ton range" just as F-22 is in the 19 ton range. This indicates 2 things about the claim. Firstly, the author views anything under 16 tons as within the 15 ton range (since F-22 is 19.7 tons, easily rounding to 20 tons if he was rounding, but he's not). Secondly, J-20 is likely very high on the 15 ton range, which means just under 16 tons since they had to "control it to" its current weight. So I've always taken the author's words as much closer to 16 tons than 15, maybe just a hair under 16. 16 tons is actually an 18.8% reduction in weight from F-22, not 25% and quite similar to the 17% reduction that Brat is so certain of for J-31.
Quite frankly, I would think that anyone who thinks that J-31 weighs a similar amount to the dimensionally-similar MiG-29 would have no trouble seeing J-20 weigh roughly what the dimensionally-larger Flanker does... unless... he... didn't know what they weighed in relation to each other and was only finding out the implications of what he was saying as he read the responses.
Jura The idiot
General
dumb question: will you guys ever know the weight? I mean will it be officially confirmed at some point, or if I come to this thread after ten years, you'll be still guessing LOL
@Tirdent (Trident): Please note that the Lyulka designer is talking about the TVC on the AL-31, not the massive bomber engine that was installed onto a Russian prototype. Let me put it this way, I'm not bashing the F-22. It is probably the most IR-stealthy fighter in existence at this moment, and what heavy TVC nozzles on the F-22 imply is that the aircraft has suffcient thrust to overcome the weight penalties imposed by heavy TVC. Of course, if you look at the rest of the article, he's talking about carbon-carbon design for next-generation engines, when we know that the United States already has a next-generation engine with "ceramic matrix RAM", implying that the F119 is not limited by the Lyulka's antiquated flat nozzle TVC technology.
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Lieutenant General
I'm not guessing the weight; I'm saying we should remain open-minded about the possibilities, especially those that are published in semi-reliable sources that claim to have gotten their info from Chengdu.
The only people who are actually guessing the weight are those who claim it has to be heavier than F-22 or place a number like 20 or 21 tons based on nothing except their own eye-balling of volume and assumptions of density, in other words, making up numbers when you don't have them.
If anyone was halfway serious about this, the least he should do is develop/use a program to render 3D models of both jets, enter the relatively known data for length and wingspan, and use that to actually get in silico calculations for volume of both aircraft. That would be a very basic start. Just get the volume numbers. Even then, you couldn't definitively draw weight conclusions because you don't have density data. I don't understand how anyone could be so delusional as to think that they could arrive at a number doing this with eyeballing and guesstimating.
Of course we will! (our team knows with-in a 1,000 lbs what the J-20 weighs), this isn't rocket science, and its unlikely that China will ever divulge the J-20s weight willingly,,, like I said, who really cares what the J-20 weighs, but its a known quantity.. more importantly, we know how well it performs.. We know its thrust, we know its weight,, no doubt we know within a few gallons how much fuel it carries, and exactly what will be in those weapons bays when the doors close, oh and don't forget we know about the radar, the ejection seat, and how many hours they can reasonably expect to get out of those Russian AL-31FN's
Truth be told, this discussion is NOT about weight, but about intellectual honesty!
and for the record, I've NEVER been in the military, other than having a very early USAF part and serial number stamped at the TOP of my right butt cheek,, Govt Issue #1 Son, serial # 000000056-1,,, that pleasant looking gentlemen in the picture is my dear old Dad,,, I can tell he's having a great day by the smile on his face!
remember, "imitation", remains the sincerest form of flattery"
and with the Russian's flying their SU-35's in Syria, we know the numbers on that score as well!
The RD-93 isn't a scaled down F135 though
The latter is 25 years more modern in technology, achieving a 30% higher pressure ratio with 40% fewer compressor stages. All else needs to be equal, as I said (it was a thought exercise to address the argument that more engines = more weight).I realize that, but even 16t is hardly any more credible than 15t. Anything substantially below 21t requires a step change in airframe structure technology and/or compromises in capability (e.g. lower g-limit).
From the F-22, but being significantly larger than the Raptor, a J-20 built with approximately the same technology level will be heavier (around 21t), so realistically you need to take that figure as the basis, as I said.
The Flanker (and the MiG-29, for that matter) are 4th generation fighters - they are not accurate benchmarks for 5th generation fighter weights, else why is the F-22 heavier than the Su-27?
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Lieutenant General
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There was no bomber engine on the Flanker test bed, it was an AL-31F with a tech demo nozzle for that power plant (the F135 nozzle design was first tested on an F100 in an F-16 too).