Chengdu J-20 news and analysis Part III

[flateric]

https://www.youtube.com/watch?v=4G0U0LZqf4Y

slightly better quality vid

 

[Deino]

The issue raised up again with this latest CCTV-report that got some hype by the usual suspects in certain forums as being prove that the WS-15 is ready, that the WS-15 is available already in 4 versions and the most powerful one delivering 24t of thrust.

lol

Yes it is indeed surprising what some people have in mind.

Anyway to admit, my hope was, that anyone would/could identify this certain part as part of either from an AL-31FN or from a WS-10, since IMO these are the only realistic options. I cannot believe that would be - besides the established WS-10 and the WS-15 still under development - yet another high-thrust powerplant in China available.

Or does anyone has more and better info ?

Deino

 

[thrax]

Deino how they say 'Aegean ghost' camo in Han Chinese? B)

 

[Deino]

For the first time, a J-20A LRIP was spotted with a variant of the WS-10 'Taihang' - maybe the IPE - but fitted with serrated nozzle feathers.

Of note are the typical internal structures of the nozzle (for comparison on a WS-10A fitted to a J-11B).

 

[LowObservable]

I found this adjacent to the same photo. Translation of caption would be welcome. The J-20's expression needs no translation...

 

[raptor82]

I found this adjacent to the same photo. Translation of caption would be welcome. The J-20's expression needs no translation...

"Don't worry ,the (anorectal) surgery will be completed soon. Remember,don't eat too-spicy 火锅（hotpot dishes）next time."

 

[Deino]

I found this adjacent to the same photo. Translation of caption would be welcome. The J-20's expression needs no translation...

via: https://twitter.com/boweconstrictr/status/904441827570458624

"Relax, the operation will be done soon. Remember from now on not to have such spicy things in hotpot!" ;D

 

[siegecrossbow]

Image of J-20 with WS-10B.

http://chinese-military-aviation.blogspot.co.id/2012/07/fighters_18.html

 

[Deino]

Image of J-20 with WS-10B.

http://chinese-military-aviation.blogspot.co.id/2012/07/fighters_18.html

Already posted yesterday !

BY the way I missed to post this one .... :-*

 

[Triton]

September 17, 2017

High speed taxiing of WS-10B powered J-20 2021, maiden flight in a few days via fyjs.

Source:
https://china.liveuamap.com/en/2017/18-september-high-speed-taxiing-of-ws10b-powered-j20-2021

 

[Deino]

Maiden flight successfully accomplished yesterday ... sadly only this gif available. ???

 

[FighterJock]

Interesting GIF Deino, pity there is no actual video footage available. Time will tell if they release any.

 

[Triton]

"Professional notes: The U.S. F-35 versus the PRC J-20"
Proceedings Magazine October 2017
by Dr. Mark B Schneider

Source:
https://www.usni.org/magazines/proceedings/2017-10/professional-notes-us-f-35-versus-prc-j-20

 

[Blitzo]

"Professional notes: The U.S. F-35 versus the PRC J-20"
Proceedings Magazine October 2017
by Dr. Mark B Schneider

Source:
https://www.usni.org/magazines/proceedings/2017-10/professional-notes-us-f-35-versus-prc-j-20

A poor piece, really poor effort.

First sentence calling it a strike fighter/interceptor raises some eyebrows is a bit concerning, and the statement about presence or lackthereof regarding its gun is even more so.

I'm not sure what A2A missile J-20 has been seen externally carrying because none have been seen being carried that way (he may be thinking of PL-X that J-16 and J-11B have been seen carrying).

J-20's weapon bays are obviously nowhere near large enough to carry an A2G weapon with a "600 mile range".

Calling J-20's radar an "early" AESA from the Chinese industry is also a bit strange, given they've had AESAs aboard a number of different platforms in service for over a decade now. Maybe he meant fighter AESA, but then that doesn't carry the same connotation.

I'm also surprised at the notion of more J-20s being produced than F-35s, that gave me a laugh.



It seems like an article that someone with an academic and military background but with near zero prior familiarity with the J-20 (or indeed the Chinese military) itself, wrote with a one week deadline, with the option to use open sources/internet.


A professional might have written this piece, but unfortunately the fellow is an amateur in Chinese military matters.

 

[totoro]

To nitpick, J-20s bay MAY one day be able to hold a2g weapons with 600 mile range. Case in point - JSOW-ER can achieve 560 km (350 miles)and can be carried by F-35. (carrying a 250 kg class warhead)

JASSM-ER is to have 920 km range (almost 600 miles) with a modified engine, carrying a 500 kg class warhead. A 620 mile range option was achievable with a completely new engine but was not pursued in development.

Making warhead smaller, 250 kg class, might enable even longer range or might enable similar 600 mile range with a slightly smaller body.

JASSM-ER is 4.27 m long, so it can fit length wise in J20's bay. With bay being 90ish cm wide, that's also doable. What's questionable is depth. JASSM seems to be some 55-60 cm tall, complete with the pylon interface. That is almost surely too much for J20, as it's unlikely depth of J20's bays is much over 35-40 cm (due to PL-15 requirements)

So basically it'd have to be a weapon 4,3 m long, with cross section dimensions of 35-40 cm height and 80-90 cm wide. (to compensate for the height loss to overall volume). That'd still fit in one of J20's bomb bay but it'd have to be a novel, daring, semi blended wing/body design.

Or if warhead is just 250 kg then it might be something in between, perhaps 40 by 70 cm cross section...

It seems doable, when Chinese engine tech catches up. Just not likely efficient or plausible for the forseeable future.

What does seem perfectly plausible even with current Chinese engine tech is a 300+ km range stealthy a2g missile, basically a bit longer and wider JSOW.

 

[stealthflanker]

Or for now it does not need to rely on standoff weapon. but employed in similar manner as F-22's. Rely on stealth to penetrate. Release multiple weapons (Say L-100's) the supercruise to evade SAM's or fighters.

 

[Blitzo]

To nitpick, J-20s bay MAY one day be able to hold a2g weapons with 600 mile range. Case in point - JSOW-ER can achieve 560 km (350 miles)and can be carried by F-35. (carrying a 250 kg class warhead)

JASSM-ER is to have 920 km range (almost 600 miles) with a modified engine, carrying a 500 kg class warhead. A 620 mile range option was achievable with a completely new engine but was not pursued in development.

Making warhead smaller, 250 kg class, might enable even longer range or might enable similar 600 mile range with a slightly smaller body.

JASSM-ER is 4.27 m long, so it can fit length wise in J20's bay. With bay being 90ish cm wide, that's also doable. What's questionable is depth. JASSM seems to be some 55-60 cm tall, complete with the pylon interface. That is almost surely too much for J20, as it's unlikely depth of J20's bays is much over 35-40 cm (due to PL-15 requirements)

So basically it'd have to be a weapon 4,3 m long, with cross section dimensions of 35-40 cm height and 80-90 cm wide. (to compensate for the height loss to overall volume). That'd still fit in one of J20's bomb bay but it'd have to be a novel, daring, semi blended wing/body design.

Or if warhead is just 250 kg then it might be something in between, perhaps 40 by 70 cm cross section...

It seems doable, when Chinese engine tech catches up. Just not likely efficient or plausible for the forseeable future.

What does seem perfectly plausible even with current Chinese engine tech is a 300+ km range stealthy a2g missile, basically a bit longer and wider JSOW.

Oh I definitely do think that a weapon developed specifically for J-20's weapons bays could potentially be fairly long ranged, like 300+km.

But talking about the notion of a 600+ mile range weapon for J-20 as if such a weapon already exists (which the article suggests), is just ludicrous.

 

[Deino]

Also, not sure if You know the original report and he indeed misquoted me or - IMO even worse - gives a hint to a wrong conclusion:

1. My original report said nothing to manoeuvrability but I said "...at least until the planned WS-15 engine is available. In the meantime, the J-20's engines are probably adequate and will provide flight performance at least comparable to the latest J-11B fighter." (in quote 3)

Even worse he did not differ between a Su-27 and Su-33 ...

2. Also he implied another conclusion: “As for the development of a genuine 5th generation combat aircraft, China obviously has a long way to go.” This is an apparent reference to China’s problems developing advanced engines and avionics. (in quote 5) This was also meant regarding the still not available WS-15.

3. And finally ... (in quote 8): Andreas Rupprecht writes “The J-20 is most likely no match for the F-22 and the F-35…” Again a misquote: My original sentence was ... "As regards to stealth the J-20 is most likely no match for the F-22 and the F-35 (see the non-stealthy engine exhaust, the uncovered countermeasures launchers and other details)."

Deino

 

[Triton]

"China's J-20 fifth-gen fighter moves into series production"
Reuben F Johnson - IHS Jane's Defence Weekly
26 October 2017

Source:
http://www.janes.com/article/75232/china-s-j-20-fifth-gen-fighter-moves-into-series-production

Key Points

The CAC J-20 fifth-generation fighter will soon move into series production, according to a CCTV report
The type may be brought into service before achieving FOC

The Chengdu Aerospace Corporation (CAC) J-20 ‘fifth-generation’ multirole fighter will soon enter series production and is on a path towards achieving full operational capability (FOC) with the People’s Liberation Army Air Force (PLAAF), according to a 23 October report on China Central TV’s (CCTV) Channel 4, which is the military channel of the state-run broadcasting service.

The broadcast showed a group of five J-20s in formation, which is the largest number of the type seen flying simultaneously in any publicly viewed display.

The aircraft did make a brief ‘fly by’ appearance at last year’s Airshow China, held last November at Zhuhai in China’s Guangdong province, but there were only two aircraft in the flight display. Additionally, the aircraft were based at an aerodrome in nearby Foshan, so they never landed or were parked on the static display line at Zhuhai.

According to the CCTV report, the aircraft has entered what is referred to as “stable” mass production, which is interpreted as meaning there is now a fixed, regular production rate in order to create some minimal economies of scale. The production rate is expected to reach as much as three aircraft per month. Representatives of the company who spoke to CCTV reportedly said there should be more than 100 J-20s produced by the end of 2020....

 

[TomcatViP]

3/month for such a project is impressive:
- it's a large fighter
- involving the utmost of Chinese tech from the last 5/10y with a very short time to adapt (and dev) to new and appropriate manufacturing techniques
- It is a stealth airframe (think precision manufacturing of large seamless panels, coating etc...)

So this is interesting. If they stick to the plan, we will have 100+ fighters in less than 36 months, a very capable asset for tactical deterrence. No other country, outside of the US and F35 users will be able to match this in time, setting a new stepping stone and ground level among military.

This what the Fr head of Staff said when he mentioned in front of the defense commission the new reality: "we are now outpaced in technology where we should not and this is troubling". (from my mem, please refer to proper source for an exact quote)

 

[LowObservable]

First, you have my sympathy, Deino. You weren't the only one mis-cited or misquoted.

Second, 36 a month* by 2020 is another massive intelligence failure. Remember when Gates &co didn't expect any Chinese stealth fighters by 2020?

* [EDIT] 36/year. Morning coffee had not kicked in. However:

"Gates said in 2009 that China was not expected to have a fifth-generation aircraft by 2020 and no more than a handful by 2025."

http://www.reuters.com/article/us-usa-china-fighter/u-s-downplays-chinese-stealth-fighter-status-idUKTRE7042X820110105

 

[sferrin]

36 J-20s a month? (432/yr.) is higher than the highest F-16 build rate at the height of the Cold War. I'll believe it when I see it.

 

[Airplane]

First, you have my sympathy, Deino. You weren't the only one mis-cited or misquoted.

Second, 36 a month by 2020 is another massive intelligence failure. Remember when Gates &co didn't expect any Chinese stealth fighters by 2020?

That was the argument to cancel the Raptor. It wasn't an intelligence failure... It was a lie.

 

[sferrin]

First, you have my sympathy, Deino. You weren't the only one mis-cited or misquoted.

Second, 36 a month by 2020 is another massive intelligence failure. Remember when Gates &co didn't expect any Chinese stealth fighters by 2020?

That was the argument to cancel the Raptor. It wasn't an intelligence failure... It was a lie.

As I recall, at the time there was some question that Gordon England, who had a personal grudge with Lockheed, and was Gates' assistant, might have had some influence there.

 

[RadicalDisconnect]

J-20 and Su-35 together. Guess now we can finally take a ruler and measure the size?

Deino at SDF did a pixels measurement and the J-20 seems to be about 20.9 m long or 68.7 ft.

 

[Mike Pryce]

Second, 36 a month* by 2020 is another massive intelligence failure. Remember when Gates &co didn't expect any Chinese stealth fighters by 2020?

* [EDIT] 36/year. Morning coffee had not kicked in. However:

"Gates said in 2009 that China was not expected to have a fifth-generation aircraft by 2020 and no more than a handful by 2025."

http://www.reuters.com/article/us-usa-china-fighter/u-s-downplays-chinese-stealth-fighter-status-idUKTRE7042X820110105

One thing the Chinese seem not to have copied is Western project management/risk reduction etc.. Like Sydney Camm 'as quick as you bloody well can' seems to be the approach. And it seems to work. I would imagine quicker also means much cheaper. Maybe other countries will pinch that from China?

 

[latenlazy]

J-20 and Su-35 together. Guess now we can finally take a ruler and measure the size?

Deino at SDF did a pixels measurement and the J-20 seems to be about 20.9 m long or 68.7 ft.

I personally think Deino slightly overestimated the length and slightly underestimated the wingspan. For the J-20 he chose to use (the one on the right) you can see the vertical tail extends further out than the stingers, but in the plane in the center this is not the case. This suggests some degree of distortion, where because the vertical tails are taller they're closer to the camera, and will seem bigger, which can make them look like they're extending out more. Because of that I would recommend using the stinger as the tip of the tail end of the plane and not the vertical tails. I'll also note that the Flanker in the center of the image is positioned slightly at an angle relative to the J-20s. If you draw a straight line from tip to tip of that Flanker both lengthwise and widthwise, that slight angle will have the effect of making the Flanker seem both shorter and wider than the J-20 than it actually is, which in turn will skew estimates of the J-20's dimensions toward longer and narrower. My recommendation would be to isolate the Flanker in the center and rotate it a half a degree or slightly more to straighten it up first before taking measures.

 

[sferrin]

Deino at SDF did a pixels measurement and the J-20 seems to be about 20.9 m long or 68.7 ft.

Heh. I came up with 20.8m about year ago and was roundly poo-pooed.

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295664.html#msg295664

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295674.html#msg295674

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295723.html#msg295723

 

[LowObservable]

Beware the wide-angle lens. There's distortion towards the edges of the image - note the outward "lean" of the J-11 tails. Even the pair of J-20s show different tail angles.

Say what you like about satellites... at least they're 500 kilometers up, which is as close to infinity as one needs to get. My guess is this was shot from a consumer drone.

 

[Mat Parry]

Beware the wide-angle lens. There's distortion towards the edges of the image - note the outward "lean" of the J-11 tails. Even the pair of J-20s show different tail angles.

The implication being that the J-11's appear longer in this photo than they are in reality? Resulting in an underestimation of the J-20 length?

Edit!
I've confused myself reading about barrel distortions... I think the J-11 at the edge of the photo would appear shorter than it actually is...

 

[starviking]

Perhaps the square patterning on the runway could be used to provide some correction for distortion?

 

[Mat Parry]

A very good point

 

[latenlazy]

Deino at SDF did a pixels measurement and the J-20 seems to be about 20.9 m long or 68.7 ft.

Heh. I came up with 20.8m about year ago and was roundly poo-pooed.

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295664.html#msg295664

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295674.html#msg295674

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295723.html#msg295723

If you felt "poo-pooed" by my comment, then you should know that it was for your choice of methodology. Getting the estimate close doesn't change what a poor methodology arbitrarily trying to match feature sizes of two very different planes is.

 

[sferrin]

Deino at SDF did a pixels measurement and the J-20 seems to be about 20.9 m long or 68.7 ft.

Heh. I came up with 20.8m about year ago and was roundly poo-pooed.

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295664.html#msg295664

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295674.html#msg295674

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295723.html#msg295723

If you felt "poo-pooed" by my comment, then you should know that it was for your choice of methodology. Getting the estimate close doesn't change what a poor methodology arbitrarily trying to match feature sizes of two very different planes is.

If you get the right answer then it wasn't a "poor methodology". Not any worse than any others being used certainly. "Two different planes" yes. Two different canopies? Nope. Sure, I'd preferred to have a handy known item next to the J-20 to use for reference, but you use what you have.

 

[Trident]

Playing around with the image (using various J-16s and J-20s, rotating the middle J-16 before measuring it, comparing the pixel sizes of the 5x6 concrete slab arrays around the middle J-16 and middle J-20...) I get:

Length 20.9 +-0.1m
Span 12.9 +-0.1m

So yes, I would agree that Deino is underestimating span by a significant amount, but his result for length seems pretty accurate to me. As you might surmise from the fact that I'm providing error margins, I certainly don't think this image allows an estimate to within less than 0.2 to 0.1m anyway.

EDIT: I should perhaps add that I measured the J-20 from nose tip to tail shelf tip - looking at a couple of almost perfect beam photos of late J-20 prototypes (with the extended shelves), the fin TE tip is NOT the rear most point.

 

[Deino]

Another attempt ... (left my previous try)

... problem is, the J-16 is a bit distorted and the J-20's radome-tip is not exactly visible.

 

[latenlazy]

Deino at SDF did a pixels measurement and the J-20 seems to be about 20.9 m long or 68.7 ft.

Heh. I came up with 20.8m about year ago and was roundly poo-pooed.

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295664.html#msg295664

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295674.html#msg295674

https://www.secretprojects.co.uk/forum/index.php/topic,15609.msg295723.html#msg295723

If you felt "poo-pooed" by my comment, then you should know that it was for your choice of methodology. Getting the estimate close doesn't change what a poor methodology arbitrarily trying to match feature sizes of two very different planes is.

If you get the right answer then it wasn't a "poor methodology". Not any worse than any others being used certainly. "Two different planes" yes. Two different canopies? Nope. Sure, I'd preferred to have a handy known item next to the J-20 to use for reference, but you use what you have.

Uhhh yeah that wouldn't fly in *any* of my science or math classes. You'd get zero points for getting the right answer with the wrong approach.

Oh they're the same canopies are they? Where's your evidence? Or is this one of those magical eyeball facts? Ever heard that it's often better to not presume if you don't have food facts?

 

[Blitzo]

my own take

 

[stealthflanker]

You all did nice work. So At most it's about 21m or just as long as Flanker. and the wingspan is less.

 

[latenlazy]

Okay, finally got my laptop with photoshop back. I straightened out both the Flanker and J-20 in the picture to the best of my abilities. For the Flanker I got 204 pixels for the length and 136 pixels for the wingspan (I included the wingtip pylons...wasn't sure whether the Flanker's wingspan should include that, but I figure it should since it's a staple of the design). For the J-20 I got 193 pixels for the length and 120 pixels for the wingspan. That makes the J-20 about 20.7~20.8 meters long, with a wingspan of just roughly 13 meters. I'll note though that if you try to retroactively reconstruct the lengths of the Flanker and J-20 using the wingspan estimates you will get 22.05 meters in length for the Flanker and 20.9 meters in length for the J-20. Do this exercise in reverse, and you get a wingspan of 14.62 meters for the Flanker and 12.9 meters for the J-20. At first I thought this was distortion, but more likely than not it's actually measurement error from the the low pixel count from the images. Every pixel contributes about 0.1 meters of error. Without higher quality pics this is about as close as we can get, I think.

I also tried to measure the angle of the J-20's leading and trailing edge sweeps. The leading edge seems to be about 48 degrees, though with the distortion and pixelation it was kind of hard to tell. My measurements varied between 47 degrees and 49 degrees for the three different planes in the original picture, so I figure all things considered with perspective and camera tilt the actual figure would probably be squarely in the middle. The same problems applied to the trailing edge, though I arrived at 12 degrees.

Using the sweep angles, we can use an alternative approach to calculating wing area other than the trapezoidal area method which might incur fewer measurement errors. This method breaks the reference wing into three sections—an isosceles triangle with the wingspan length as the base and equal opposite angles of the leading edge sweep (48 degrees), a long rectangle with the width of the wingspan and the height of the wingtip length, and another isosceles triangle with the the wingspan length as the base and equal opposite angles of the trailing edge (12 degrees).

When I tried the trapezoidal method I got a midchord length of 9.95 meters and a wingtip length of 1.6 meters. That equals an wing area of 75 m^2. Using the alternative method I'm suggesting, I got 46.92+8.98+20.8, which adds up to 76.7 m^2. The difference isn't big, but I think if we know the wingspan and the wingtip length we can save ourselves the trouble of trying to estimate yet another length since the wing sweep angles give us constants to work with.