That specific shot is probably a studio mockup with a green screen.
J-20 5th Gen Fighter Thread VI
- Thread starter siegecrossbow
- Start date
- Status
There's a lot more to material and structural engineering than just the strength to weight ratio of the materials being used.
There's another line of thought to be discussed when talking about weight. How many examples of fighter aircraft have there been where:
A) advanced construction methods in the next generation planes have resulted in overall significantly lower empty weight (for comparable in size and role planes)?
B) next gen plane design priorites were set up in such a way that less subsystems were present than in previous gen? Or that plane was planned to be as less multirole or to have a shorter lifespan?
Another unrelated thought: How likely is it that two variants of j20 are designed and engineered? One optimized for ws10/al31 and another one, redesigned and optimized for a different weight distrubution (ws15) and 20% or more thrust increase?
If there is one optimization to be had, is it more likely it would be optimized for the ws10, or for ws15 or for values in between?
If there was an outside chance in hell we'll get an official figure in the next decade or so, I'd open a betting pool here. But since it's extremely unlikely we'll get any empty weight figures until J20 is ever exported - it's a bit pointless.
A) advanced construction methods in the next generation planes have resulted in overall significantly lower empty weight (for comparable in size and role planes)?
B) next gen plane design priorites were set up in such a way that less subsystems were present than in previous gen? Or that plane was planned to be as less multirole or to have a shorter lifespan?
Another unrelated thought: How likely is it that two variants of j20 are designed and engineered? One optimized for ws10/al31 and another one, redesigned and optimized for a different weight distrubution (ws15) and 20% or more thrust increase?
If there is one optimization to be had, is it more likely it would be optimized for the ws10, or for ws15 or for values in between?
If there was an outside chance in hell we'll get an official figure in the next decade or so, I'd open a betting pool here. But since it's extremely unlikely we'll get any empty weight figures until J20 is ever exported - it's a bit pointless.
Advanced construction methods generally haven't led to significant decreases in weight because designers have historically tended to spend those weight savings to expand other capabilities, like increasing ordinance carriage capacity or expanding the sensor suite. This tendency is further compounded by corresponding increases in thrust, so a lot of emphasis is put on the engine to push kinematic performance rather than the airframe. Similarly, reliable clockwork improvements in thrust is why we've seen each subsequent plane generation with a broader set of roles (which, consequently, also puts increasing load demands on the plane's structure). I think that noting how *thrust* has been the main driver of these trends poses interesting questions about how the PLAAF might think about what to focus on and optimize for the J-20's design. On that line of thought, it's also interesting to note that almost two decades in, neither the J-11 nor J-10 seem to have seen much expansion of capabilities and roles beyond A2A combat. That's one of the reasons why I've become skeptical of the notion that the J-20 was designed (at least initially) with at least some mind for strike roles, even if secondary ones.
I don't think shortening the lifespan of the airframe to save weight is a *likely* thing for the PLAAF to do, *but* if the cadence of generational turnover for their fleet is expected to be faster due to rapid advances in technology or if the number of airframes expected to operate with inferior engines is limited, it would certainly be a creative way to go about the problem.
The longer we wait for a WS-15 the more likely it will be that a J-20B(C?) might have structural revisions. After all, we know both the J-11 and J-10 supposedly had some structural improvements done on them with each new version, mostly in the materials department, and often with weight saving touted as a primary goal.
Yano, I'm still holding out hope we'll see some official specs in next year's Zhuhai...Also, I imagine that if they really were able to shave the J-20's weight down to 15 tonnes while keeping all the bells and whistles I would have a hard time believing that someone wouldn't eventually find a way to brag about it. It would be too good a PR goodie not to be. Not only would it be good propaganda material, but it could serve to bolster the image and reputation of China's own budding aerospace industry. That might suggest the longer we go without hearing anything about the plane's weight, the more unlikely it is to be anything spectacular. Then again, maybe they already *are* bragging about it and we're just not getting the message...(the 15 tonne claim does come from a trade magazine after all...).
by78
General
The radome serrations look right to me, but the aperture and radome creases are definitely missing, both of which are easy to remove digitally, and were probably removed at the behest of the PLAAF. I can see why the aperture was removed, but the radome creases seem innocuous enough to be kept as they were, unless they served an as-of-yet unknown function or possibly give away clues the military wanted kept secret (dimensions of the radome perhaps? Because they do provide nice visual references to the contours of the radome and divide the radome into equal parts, which combined with scanning software that convert 2D images to 3D models, might give away too much for comfort).
Last edited:
Suscribe is authorized by Admin no ?
manqiangrexue
Brigadier
to most people, the TWR is more important than the actual weight, so giving the J-20 an old 125kN AL-31 variant for the analysis may or may not bring down the weight by some very small amount but it's a 10% loss in thrust, which you did list. If you say thrust isn't important, just weight for your analysis then it's better to leave the thrust off completely. But the way you listed it looked dishonest and biased against the J-20.
The couple hundred kg for DSI claim came at a time when lots of claims were flying and I didn't check all of them. It also didn't stand out to me because "couple hundred" is not a precise number, but your 200kg is. So I see you took a random percentage from a claim that wasn't verified and got your 200kg. Fine, given you said this is a crude thought experiment and didn't claim it to be a high quality precise analysis. I just wanted to see how you got that number.
Airframe composition, to me, does not mean only the amount of composite in the airframe; it means the amount of everything. Going from 40% titanium to 20% titanium is not a slight variation but indication of a significant shift. Given what Latenlazy said, we cannot certainly know even the direction of the shift, much less a put a number on it, so that change in mass is still an X, which may or may not be a large value, but cannot be assumed to be zero or near zero.
I did some research on the gun as you suggested and got 92kg for the gun, 140-180kg for the feed (likely 140kg) plus 480 rounds and whatever the belt that holds the rounds weighs. I guess you got 232kg empty and trimmed the sig figs? OK
The 1.8 ton figure for F-119 includes the TVC nozzles or not? To me, I thought the TVC nozzles were not included and an additional add-on.
I dunno about that. Chinese culture isn't big on bragging, plus, giving precise numbers don't impress too many people. The layman doesn't know if a jet is supposed to weigh 10 tons or 20 tons or 100 tons. Plus, since China isn't trying to export it, such precise information mostly serves foreign intelligence. If a scuffle were to happen, it would be greatly to J-20's advantage to have a foe think that he's up against a fat jet with little legs that can't climb or turn due to low TWR only to have a J-20 swing from his 12 to his 6 in less time than it takes him to blink and have him unable to shake it no matter what. If it were in charge, I'd at most let them "brag" about it being lighter than F-22 but wouldn't let them disclose info that would let anyone accurately guesstimate TWR. So I think if we do get "confirmation," it'd be via a leak.
Quickie
Colonel
Apparently according to Deino, he's already subscribed, albeit with a bit of a typo with the name.
plawolf
Lieutenant General
Just to add that something else to consider with weight saving techniques is cost.
Often, the most cutting edge technology is not immediately applied to existing products because of cost considerations. Especially for the PLA, who has a reputation for penny pinching. Just look at AESA proliferation rates in the PLAAF and elsewhere as a good example of that in action.
In addition, fighters are finely balanced machines. It’s not as simple as replacing a part made with aluminium with the same part made from carbon fibre and calling it a day.
If you reduce the weight of a key component, then the weight distribution with your plane will change, and you will need to make other changes to compensate for that.
Often, those supplementary changes eats up a lot of the original weight saving from improved materials and adds a lot of costs and delays. That’s why mods to existing designs tend to be a lot more conservative and modest than what could be achieved with a new clean sheet design.
There are exceptions, for example if the design had the new parts and materials in mind from the start, in which case room would have been reserved, but more critically, weights would have been added and/or non-essential equipment temporarily not installed where necessary to simulate the weight and balance of the plane as if it had the ultimately intended materials and parts in place all along.
In which case, once the intended part/material becomes available, they could just unwind all the added weights and install any omitted equipment and sub in the new materials/parts to keep the balance and weight the same.
So my point is two-fold. Firstly, it is rare for cutting edge materials and manufacturing technology advancements to be fully applied to existing designs. So looking at the weight and performance gains achieved with existing designs is not really a good reflection of what could be achieved if those same materials and manufacturing techniques are applied to a new design that planned for those new materials and techniques and the weight savings and performance gains they would yield.
Secondly, just because we do not see the latest cutting edge manufacturing and materials technologies applied to existing military or commercial designs, that are far more price sensitive, does not necessarily mean a nation does not have the knowhow to make and use those cutting-edge materials and technologies if, as is the case with premiere 5th gen air dominance fighters like the F22 and J20, price is really not an issue.
That is also why we tend to see a big jump in performance between newly developed designs and existing designs modified with the latest tech even when the two programmes might be done by the same country/company and roughly the same time.
Often, the most cutting edge technology is not immediately applied to existing products because of cost considerations. Especially for the PLA, who has a reputation for penny pinching. Just look at AESA proliferation rates in the PLAAF and elsewhere as a good example of that in action.
In addition, fighters are finely balanced machines. It’s not as simple as replacing a part made with aluminium with the same part made from carbon fibre and calling it a day.
If you reduce the weight of a key component, then the weight distribution with your plane will change, and you will need to make other changes to compensate for that.
Often, those supplementary changes eats up a lot of the original weight saving from improved materials and adds a lot of costs and delays. That’s why mods to existing designs tend to be a lot more conservative and modest than what could be achieved with a new clean sheet design.
There are exceptions, for example if the design had the new parts and materials in mind from the start, in which case room would have been reserved, but more critically, weights would have been added and/or non-essential equipment temporarily not installed where necessary to simulate the weight and balance of the plane as if it had the ultimately intended materials and parts in place all along.
In which case, once the intended part/material becomes available, they could just unwind all the added weights and install any omitted equipment and sub in the new materials/parts to keep the balance and weight the same.
So my point is two-fold. Firstly, it is rare for cutting edge materials and manufacturing technology advancements to be fully applied to existing designs. So looking at the weight and performance gains achieved with existing designs is not really a good reflection of what could be achieved if those same materials and manufacturing techniques are applied to a new design that planned for those new materials and techniques and the weight savings and performance gains they would yield.
Secondly, just because we do not see the latest cutting edge manufacturing and materials technologies applied to existing military or commercial designs, that are far more price sensitive, does not necessarily mean a nation does not have the knowhow to make and use those cutting-edge materials and technologies if, as is the case with premiere 5th gen air dominance fighters like the F22 and J20, price is really not an issue.
That is also why we tend to see a big jump in performance between newly developed designs and existing designs modified with the latest tech even when the two programmes might be done by the same country/company and roughly the same time.
Trident said:Bltizo said:
There is no previous account for me to use, Tirdent was deliberate (though I do not mean to disillusion AFB) - there is already somebody else here registered under the username Trident. No big deal, Trident is not a nickname which is so exotic that you can just expect it not to be taken on a long established forum.
Totoro said:
Ordinarily it would be silly, agreed, but having signed up I found that (per the forum main page) the latest confirmed member dates from July! Having to wait several days for confirmation is one thing (and annoying enough already, when you intend to respond to specific posts), waiting a third of a *year* turns the whole thing into rather a farce.
- Status