J-20 goes operational again

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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milosh

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Unread post08 Jan 2021, 17:48

mixelflick wrote:OK Milosh, let's say you're an engineer who's tasked with building the ultimate air to air machine..

Do you use a flat nozzel, incur the weight penalty but preserve maximal stealth? Or do you go with a round engine nozzel, trying to eek out additional thrust and compromise on the stealth thing?


I didn't say it is bad I only point out it is quite heavy solution.

Btw I think in 1980s flat nozzle was only real solution for rear stealth, Soviets developed them too, but then in 1990s you have LOAN nozzle which show round stealth nozzle can be done.
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tphuang

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Unread post08 Jan 2021, 21:03

milosh wrote:Canard configuration isn't good because canards are radar reflectors in case of J-20 huge one:
https://i.redd.it/pfw4j47mqik11.jpg

J-20 canards don't have platform alignment. So you have quite long surfaces which aren't angled as wings not good at all from stealth point of view:
https://geopolitics.news/wp-content/upl ... -00599.jpg

I believe J-20 has same number of moving surface as F-22. By itself, I don't see why Canard moving is necessarily going to be more detrimental to stealth than those movable services like Su-57's levcon or your usual leading edge slats and flaperons.

It seems to me the leading edge of J-20 canards are planform aligned with the main wing structure. I don't know enough to comment on the trailing edge angle vs other surfaces, but I've seen them do a lot of work on the trailing edge like radar dispersing sawtooth pattern. And I think the canard probably has quite a bit of RAM applied to it. So it does seem to me they put a lot of attention on trying to minimize the returns once they decided this was a trade-off they are willing to take.

If I had to guess, it will be hard for them to achieve the same level of stealth as a more conventional layout. But I never thought J-20 was at F-22/35 level of stealth even from front.
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jessmo112

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Unread post08 Jan 2021, 23:57

Chinese engineers ordered to keep working on J-20 engine until it matches the F-22s engine.

https://www.google.com/amp/s/amp.scmp.c ... ian-engine


Pft nearly 20 years to surpass the Russians?
And you want a f-119? GL with that!
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jessmo112

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Unread post09 Jan 2021, 00:06

Milosh.

My buddy at work was offered a blind date by his mom.
Some girl from Ohio I think. When he asked his mom how she looks the 1st response was. "Well shes not THAT big". This is how you sound with the J-20 she is fat and we know it. Shes not petite! Shes not graceful Shes fat!
Shes not going to keep up with a F-35 its not even just TW, that long fuselage with a gigantic movement arm wont be able to whip around fast enough.
They are estimating the F-35s ITR is below 28 degrees a sec. She IS FAT! Stop trying to convince us ofherwise orxsell us this pig!
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wrightwing

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Unread post09 Jan 2021, 04:54

jessmo112 wrote:Milosh.

My buddy at work was offered a blind date by his mom.
Some girl from Ohio I think. When he asked his mom how she looks the 1st response was. "Well shes not THAT big". This is how you sound with the J-20 she is fat and we know it. Shes not petite! Shes not graceful Shes fat!
Shes not going to keep up with a F-35 its not even just TW, that long fuselage with a gigantic movement arm wont be able to whip around fast enough.
They are estimating the F-35s ITR is ABOVE 28 degrees a sec. She IS FAT! Stop trying to convince us ofherwise orxsell us this pig!

Fixed it for you.
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milosh

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Unread post10 Jan 2021, 16:25

jessmo112 wrote:Milosh.

My buddy at work was offered a blind date by his mom.
Some girl from Ohio I think. When he asked his mom how she looks the 1st response was. "Well shes not THAT big". This is how you sound with the J-20 she is fat and we know it. Shes not petite! Shes not graceful Shes fat!
Shes not going to keep up with a F-35 its not even just TW, that long fuselage with a gigantic movement arm wont be able to whip around fast enough.
They are estimating the F-35s ITR is below 28 degrees a sec. She IS FAT! Stop trying to convince us ofherwise orxsell us this pig!


Did I said it is more agile then F-35? Nope. Someone mentioned lack of thrust for J-20 as problem, and it sound like F-35 have much better T/W ratio, so I explain why it isn't right.

Is J-20 worse or better in agility I don't know, but T/W ratio isn't problem if we compare it with F-35 or even some praised 4gen fighters.

I agree with you long airframe is most like problem becuase big canards will turn nose fast which heavier rear will not be able to follow it, so I expect they will solved that with TVC.

Btw my grunge with F-35 dogfight capability isn't agility at all, it is lack of fast WVR pods/bays. I think it wouldn't be hard at all to have something like simple mini belly pod just to fit two wvr missiles or something else when you don't need A-A.
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weasel1962

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Unread post11 Jan 2021, 09:15

Talking about looks, AVIC released CGI of four 2 seater J-20s. Apparently the intent of the 2nd person is for battlefield mangagement, situation awarenewss & UAV control, not for strike. I would read it as an indication of a fair bit of pilot workload for the single seater pilot.

Its a sharp contrast to the F-35, which is claimed to be able to fly itself leaving the pilot to handle secondary tasks like UAV management.
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weasel1962

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Unread post11 Jan 2021, 10:56

CGI.jpg
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Scorpion1alpha

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Unread post11 Jan 2021, 13:20

If the PLAAF is in fact working on or have a 2-seat J-20 coming online soon (as the screenshot from the AVIC video shows), it would be the first family-model stealth fighter built by anyone. I have to say that'll be a good move for them. Although there's debate on whether having 2 guys in the same fighter sized aircraft is a good thing or not, I tend to believe there are some mission sets that could benefit from having the family model.
I'm watching...
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disconnectedradical

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Unread post11 Jan 2021, 13:29

The twin seat J-20 actually looks more aesthetically pleasing.

Regarding weight, the J-20 fuselage length is quite a bit longer, so I'm not expecting it to much lighter than an F-22, but on the other hand, if most of that length is empty space for fuel tanks, it may not be as heavy as it looks. I would think something in the neighborhood of 45,000 lbs is likely. With the longer fuselage the fuel load of this aircraft may actually be quite substantial.

I don't buy Chinese propaganda (they don't actually say much about this aircraft), but jessmo's gloating looks like nationalist chest beating. He might not take it seriously, but USAF certainly is, and USMC certainly is.
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mixelflick

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Unread post11 Jan 2021, 17:28

milosh wrote:
jessmo112 wrote:Milosh.

My buddy at work was offered a blind date by his mom.
Some girl from Ohio I think. When he asked his mom how she looks the 1st response was. "Well shes not THAT big". This is how you sound with the J-20 she is fat and we know it. Shes not petite! Shes not graceful Shes fat!
Shes not going to keep up with a F-35 its not even just TW, that long fuselage with a gigantic movement arm wont be able to whip around fast enough.
They are estimating the F-35s ITR is below 28 degrees a sec. She IS FAT! Stop trying to convince us ofherwise orxsell us this pig!


Did I said it is more agile then F-35? Nope. Someone mentioned lack of thrust for J-20 as problem, and it sound like F-35 have much better T/W ratio, so I explain why it isn't right.

Is J-20 worse or better in agility I don't know, but T/W ratio isn't problem if we compare it with F-35 or even some praised 4gen fighters.

I agree with you long airframe is most like problem becuase big canards will turn nose fast which heavier rear will not be able to follow it, so I expect they will solved that with TVC.

Btw my grunge with F-35 dogfight capability isn't agility at all, it is lack of fast WVR pods/bays. I think it wouldn't be hard at all to have something like simple mini belly pod just to fit two wvr missiles or something else when you don't need A-A.


Regarding your last point... you really think the current weapons bays aren't "fast" enough in opening/closing to get an AMRAAM (or other AAM) out WVR? Is that what you mean?

I have to believe LM and USAF took this into consideration. I know AIM-9x isn't carried internally, but it is externally and I tend to think the F-35 still qualifies as a LO bird carrying them. I seem to recall some discussion about the hardpoints being treated with LO coatings, angled just so etc.
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jessmo112

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Unread post13 Jan 2021, 02:05

milosh wrote:
jessmo112 wrote:Milosh.

My buddy at work was offered a blind date by his mom.
Some girl from Ohio I think. When he asked his mom how she looks the 1st response was. "Well shes not THAT big". This is how you sound with the J-20 she is fat and we know it. Shes not petite! Shes not graceful Shes fat!
Shes not going to keep up with a F-35 its not even just TW, that long fuselage with a gigantic movement arm wont be able to whip around fast enough.
They are estimating the F-35s ITR is below 28 degrees a sec. She IS FAT! Stop trying to convince us ofherwise orxsell us this pig!


Did I said it is more agile then F-35? Nope. Someone mentioned lack of thrust for J-20 as problem, and it sound like F-35 have much better T/W ratio, so I explain why it isn't right.

Is J-20 worse or better in agility I don't know, but T/W ratio isn't problem if we compare it with F-35 or even some praised 4gen fighters.

I agree with you long airframe is most like problem becuase big canards will turn nose fast which heavier rear will not be able to follow it, so I expect they will solved that with TVC.

Btw my grunge with F-35 dogfight capability isn't agility at all, it is lack of fast WVR pods/bays. I think it wouldn't be hard at all to have something like simple mini belly pod just to fit two wvr missiles or something else when you don't need A-A.


1. The AMRAAM can be used WVR. This is irrelevant though since they only seanrio used use it this way was with an escort of some kind gone hot. Its more likely that if if the F-35A is WVR then all missiles are exspended and we are going to guns.

2. I hope you know that even the Aim-9 X Can be fired from almost BVR.

3. This is to slow? https://youtu.be/b0lcla1NtK8

Opposed to what putting the weapon on the bay door?
If this is the case both the F-35 and J-20 are both choosing to put IR missiles in the air stream if they are going to lug them.

This seems like grasping for straws The F-35 has missiles in the wind, so does the J-20. The F-35 has to open a bay so does the J-20.
The deciding factor will be.
A. Numbers of aircraft facing each other.
B. Force multipliers
C. Firing solution.

The F-35 can use something other than radar for a firing solution, can the J-20? The F-35 can use 360 degree Das or the EOTS. The J-20s EOTS doesnt have the range of movement. Have they built a seamless DAS system to work? Also how does the J-20 not give up position when illuminating with radar? Have the mastered LPI? If Im war planning F-35s versus J-20 then the plan is to stay as stealthy as possible.
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inst

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Unread post13 Jan 2021, 17:32

I've actually been spending time investigating the 2000 km combat radius claim, which so far, seems as though it makes no sense unless it's incorporating external fuel tanks.

The reason the 2000 km combat radius claim matters is, well, what's good for the goose (F-35) is good for the gander (J-20). At maximum range, the F-35 is relatively crippled in terms of T/W and wing loading, and is relatively mediocre in performance. At realistic ranges, however, the F-35 can jettison fuel and get a much superior T/W and wing loading figure.

Now, if the 2000 km combat radius claim is actual, the figures I have put in a fairly good T/W / wing loading for the J-20 at realistic ranges for the same reason the F-35 is very agile at realistic ranges; it can jettison fuel, and the J-20 (expected fuel fraction around 40%, same as F-35) can jettison a even greater quantity of fuel than the F-35 to reduce its weight closer to its bare minimum than the F-35 could.

===

Problem is, for the J-20, to get to the 2000 km combat radius level, it'd need some magic tricks to get there through aircraft design. If you consider aircraft by fuel fraction, both the F-35 and MiG-31 have around 40% fuel fraction and achieve 1350 km combat radiuses, despite the MiG-31 being in an interceptor one weight class above the F-35. The D-30 engines, at least in their civilian version, aren't particularly fuel inefficient either. The MiG-31, likewise, features particularly stubby wings (1.68 length to wingspan ratio, which is much higher than the roughly 1.4 ratio of the F-22, and still higher than the 1.61 ratio of the J-20), so it's hard for me to see how the J-20 might achieve better drag reduction. The J-20's empty weight, likewise, is probably slightly better than the MiG-31, but not light enough to grant substantially better range than the MiG-31.

===

That said, under some design constraints (and this one features an internal bay!) there are some signs it could be done:

https://en.wikipedia.org/wiki/North_Ame ... 108_Rapier

This never made it to the prototype stage, but claimed a 1800 km combat radius (on turbojets no less!), weighed 23,000 tons, had a fuel fraction of about 50%, had an aspect ratio of 1.65 as well as an internal bay, and made Mach 3.

Likewise, the Chinese are claiming that under refueled conditions, the J-20 has a combat radius of 3000 km, which, in consideration of other aerial refuelings, suggests the base combat radius is closer to 2000 km.
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jessmo112

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Unread post13 Jan 2021, 21:21

This gentleman has very good insite into Chinese aviation in General. Here are some take aways.

https://hushkit.net/2021/01/11/everythi ... rupprecht/

still going to ask you…how does the J-20 compare to the F-22?
Only the PLAAF and CAC know this for sure as such, I have to admit I don’t like questions like that. On the one hand because it is not my area of expertise and on the other hand because there is hardly any information available that enables an assessment. I also dare to doubt whether I could do this at all. For me, the question is more how the J-20 compares to its predecessor in PLAAF service and even more so, how the J-20 evolved. With this in mind, I am convinced that the F-22 was actually the benchmark for CAC but I am also convinced that it was clear to CAC that developing a twin-engine heavy fighter and a stealth aircraft for the first time after the J-10 would be a huge challenge. All of this coupled with the knowledge that one has hardly any experience in this area and, above all, that the engines will still only be temporary solutions. On the other hand, it has been around 15 years since the development of the F-22 and a lot has happened in China in the area of electronics, sensors and materials since then. But, it’s important to note that the predecessor of the J-20 in PLAAF service is the ‘Flanker’ and this came from a completely different period, was for a completely different requirement and was designed by a company with vastly more experience. So in conclusion, I am sure the J-20 is no worse than a J-11B in all areas of performance, but certainly – especially with the current interim engines – it does not come close to a F-22. I do not presume to make any further judgment.

Alot more at the jump.
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element1loop

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Unread post14 Jan 2021, 01:13

Scorpion1alpha wrote:If the PLAAF is in fact working on or have a 2-seat J-20 coming online soon (as the screenshot from the AVIC video shows), it would be the first family-model stealth fighter built by anyone. I have to say that'll be a good move for them. Although there's debate on whether having 2 guys in the same fighter sized aircraft is a good thing or not, I tend to believe there are some mission sets that could benefit from having the family model.


Re teaming, in the case of RAAF's Loyal Wingman all it's PR artistic conceptual renderings have it flying with two seat shornet and E-7A. All of RAAF's small F-Shornet fleet are strike aircraft (interim replacements for F-111 retirement until replaced by a more capable deep strike aircraft), suggesting the teaming intended is strike related, i.e. ISR, PID, BDA, stand-in-jammer for preserving Shornet and weapons expended, and perhaps A2A self-escort protection advantage with an A2A interceptor (Growler back seater is already going to be too busy).

The main fight even in OCA is A2G, so it makes sense that the initial teaming is oriented towards that main fight with 2-seat strike platform control, which then matures into a more automated tool for the single seat strike, with decentralized network/SQN level control, rather than direct F-35A pilot control.

Image

Imagery of Loyal Wingman working with a single-seat RAAF F-35A simply doesn't exist.

But the UK and US loyal wingman concepts are often depicted working with a single-seat F-35. The Chinese may see value in RAAF's initial 4th-gen 2-seat and E-7A control concept, but applied to and developed firstly for a 5th-gen, to develop the advantages a J20 will need to succeed and survive in A2A, and then to a standoff A2G role verses F-22A/F-35A, then an NGAG interceptor and new missile.

So a two seat development would certainly lean towards greater advantages for a J20 force of single-seaters with a two seat in a flight of 4 mix say, plus a drone or two.
Accel + Alt + VLO + DAS + MDF + Radial Distance = LIFE . . . Always choose Stealth
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