J-20 - discussion on dimensions/weight


latenlazy

Colonel
Part 2.

the reason latenlazy tries to invalidate all volume measurements is his refusal to accept what they show
I didn't see this when I was responding to the rest of Klon's post, so I'll address this one specifically, since it seems to single me out.

Perhaps, Klon, you should apply that same judgment to yourself. Perhaps the reason you've seemed obsessed with trying to invalidate me without any actual substance is because you refuse to accept what my arguments show. If you have issues with my arguments you might look more credible actually addressing their substance rather than trying to turn our discussion into a character indictment on me. As I've said many times before, you can do whatever you want with my arguments. If you don't want to believe them then don't. If you think if my arguments aren't substantively sound, address where you don't think they're substantively sound. But, if you don't have a substantive reason other than that you just refuse to consider them because you don't like to hear them then be honest about that, instead of pretending to have genuine interest in what I have to say.
 
Last edited:

latenlazy

Colonel
  • Thread Starter Thread Starter
  • #2
Neither did AVIC Laser quote detailed data on the material properties of their 3D printed parts - but as you pointed out, it would be verifiable to a customer. Just like RCS is - didn't prevent Boeing from shooting their mouth off :)
No, but they gave a number for weight reductions. Boeing shot their mouths off with a vague qualitative statements. AVIC, if they were shooting their mouths off, would have to be quite a bit more daring if they were going to use actual numbers.

'twas a pleasure.
 

Tirdent

Junior Member
Registered Member
No, but they gave a number for weight reductions
Compared to unspecified parts which they don't manufacture themselves, and a rather round figure. Not THAT much more specific than saying "RCS is at the same level as an aircraft we don't make over an unspecified range of aspects" ¯\_(ツ)_/¯ (<- had to use that one once)
 

latenlazy

Colonel
  • Thread Starter Thread Starter
  • #4
Compared to unspecified parts which they don't manufacture themselves, and a rather round figure. Not THAT much more specific than saying "RCS is at the same level as an aircraft we don't make over an unspecified range of aspects" ¯\_(ツ)_/¯ (<- had to use that one once)
Hey. That's my emoji. Back off.

They weren't misrepresenting about the 3D printed bulkheads, which I think makes it a tad less likely that they would misrepresent their weight reduction claims as well. As I said earlier, I think there are reasons to think their motives are a bit different, and as I've said much earlier, the information context isn't exactly the same. (Think we can leave this one at that?)

We both measured fuselage cross sections in about the same way and our results for the F-22 agree quite well - I got 5.3m² (from the three-view drawing). Length to the tips of the divergent nozzle ramps I made 16.8m from the drawing.
I got about 16.8 meters too. Of the measurements I've shared, the main divergence between us is the J-20's frontal area. For fuselage width I used the most recent top view photo we used to estimate length. I won't make a claim for which estimate of fuselage width is more accurate. As I intimated in other posts, I'm actually a bit more antsy over average cross sectional area because the two planes don't taper the same along their lengths.
 
Last edited:

Air Force Brat

Brigadier
Staff member
Super Moderator
Registered Member
Nonsense is an old retired pilot thinking he knows what 2017 classified 5th gen fighters weigh. Nonsense is thinking that the F-22 can be the best forever (if it ever was, which was never proven) or that its old tech could keep down a country with the highest research funding, greatest number of engineers, and the fastest supercomputers on earth.

Prove? LOL Now I know you clearly don't know what it means to prove something but just humor me. What's the "proof?" Proof isn't what sounds likely or sounds reasonable; proof something is 20 tons means it cannot weight anything but 20 tons, case closed, no debate. Not 19, not 19.5, not 20.5, not 21. Proof of weight is when you put an object on an accurate scale and you read the number; there can be no challenge to it. Show me the "proof." Let's see how funny you can get.
actually its up to you sport, to prove your non-linear reasoning,, and you can't,,, I wouldn't waste my time responding to your 15 tonne all up combat weight, because you yourself stated that you didn't believe it either??

and of course you have to resort to "personal attacks and flame baiting", SDF Moderators have warned you against such tactics, but you persist!
 

Air Force Brat

Brigadier
Staff member
Super Moderator
Registered Member
Actually there aren't. The reason is because "prove" doesn't mean what you think it means. To prove means to use evidence, and the closest thing we have to "evidence" is a publication from a semi-official source on the weight-savings of 3D printing. Does that prove the J-20 is 15 tonnes? No, in the same way that your eyeballing and appeal to precedence doesn't disprove it.



Hey, genius, we're talking about titanium alloys. Why are you talking about an entirely different metal?



Are you literally resorting to semantics to prove your point? I don't give a flying monkey what the J-20 is "categorised" as, it doesn't prove a goddamn thing. By your genius logic, the JMSDF's helicopter destroyers should displace less than 15,000 tonnes because it's categorised as a "destroyer."

Also, SDF's credibility is not your prerogative. You have failed to bring us a single piece of news regarding PLA developments since you signed up. For all the thousands of comments you've made on SDF, none of them are of use to the people who visit this forum. Your attempt to employ SDF's name as your defence is as pitiful as it is ineffective. Might I remind you this is "SinoDefence Forum" and you haven't contributed in the slightest to furthering our collective knowledge of Sino defences.



Then why the hell are you using words like "prove" and "nonsense" and "honestly" and "credibility"? You're not Chengdu, you're not qualified to even think about using those words regarding such a blurry topic.

Stop thinking you're so much more authoritative than everyone else. The J-20's mass, as far as we know, can range from 15 to 23 tonnes. You firmly believe it's >20 tonnes, that's fine. Now stop being a condescending prick to those who don't share your belief.
you haven't come close to providing a cogent argument that the J-20 isn't 20 tons, which is the general weight range we would expect from a heavy fighter, and nowhere have you provided a convincing argument that it could possibly be 15 tonnes, but you have flame baited, made personal attacks and resorted to name calling... in the end, those who are knowledgeable about material and techniques would expect the J-20 to be in a similar weight range to the F-22, possibly even the SU-57, which could actually be somewhat lighter than the US or Chinese aircraft due to reduced internal volume??
 
you haven't come close to providing a cogent argument that the J-20 isn't 20 tons, which is the general weight range we would expect from a heavy fighter, and nowhere have you provided a convincing argument that it could possibly be 15 tonnes, but you have flame baited, made personal attacks and resorted to name calling... in the end, those who are knowledgeable about material and techniques would expect the J-20 to be in a similar weight range to the F-22, possibly even the SU-57, which could actually be somewhat lighter than the US or Chinese aircraft due to reduced internal volume??
I assume you're selectively illiterate since the last (over 10) pages are riddled with possibilities for why J-20 could be 15 tons and why it could be 20+ tons, which is why most people keep an open mind... except you, cus you just don't like the implications LOL

actually its up to you sport, to prove your non-linear reasoning,, and you can't,,, I wouldn't waste my time responding to your 15 tonne all up combat weight, because you yourself stated that you didn't believe it either??

and of course you have to resort to "personal attacks and flame baiting", SDF Moderators have warned you against such tactics, but you persist!
No, it's actually not up to me to prove J-20 is 15 tonnes at all because I never said it is. I said it could be because a semi-reliable source said it was. But since you have said it is outright impossible, the onus is on you to prove why no forces in the universe could make it so, and I see nothing convincing, mostly because nobody here has the knowledge to really address all the sciences at the level that it takes to engineer a 5th generation fighter. If he did, he would most likely by working on such a project and be forbidden from discussing it.

Not only that, you specifically said that there was PROOF that J-20 was 20 tons. So where is the proof that you said you had? You make no mention of it and instead ask me to prove the opposite? tsk tsk tsk Sad. Next time, know what accounts for proof so you don't embarrass yourself again.

What personal attack? LOL Old? Retired? Pilot? Which one's not you? Or was it "nonsense"? The word that you used?
 
Last edited:

jobjed

Captain
you haven't come close to providing a cogent argument that the J-20 isn't 20 tons, which is the general weight range we would expect from a heavy fighter, and nowhere have you provided a convincing argument that it could possibly be 15 tonnes, but you have flame baited, made personal attacks and resorted to name calling... in the end, those who are knowledgeable about material and techniques would expect the J-20 to be in a similar weight range to the F-22, possibly even the SU-57, which could actually be somewhat lighter than the US or Chinese aircraft due to reduced internal volume??
For all we know the J-20 may very well be 20 tonnes. I can't prove it's not and you can't prove it is. All we can say is there are indications from an industry source that the J-20 could have achieved 15 tonnes. COULD have achieved. Not "did"... simply "could."

You adamant insist this industry source be completely and utterly disregarded because of your
Please, Log in or Register to view URLs content!
, which is a fallacious argument. I have doubts as to the veracity of the source myself but, unlike you, I don't have the arrogance to proclaim with so much certainty that this source is false and must be dismissed.

You're not God, stop pretending you are.

And don't accuse me of "name calling" when you labelled everyone who disagreed with you a "disney princess", hypocrite.
 

siegecrossbow

Brigadier
Staff member
Super Moderator
If I may add as a reference to the discussion, the cross sectional areas of the J-20 vary across its length much more than the F-22, especially after the weapons bay section.



The narrowing of the cross-section as well as the "furrow" between the engines were implemented to better conform to area rule, which may enhance supersonic performance despite relatively weak engines.
 

Top