For a tail to tail measurement we might want to move the J-20 back a bit. The Su-27’s spike is lifted for a parachute. That would add just a bit more length to it.
I measured the J-20’s nose to be about 100 pixels, and the tip of its vertical tail to be 1175 pixels. For the Su-27 the tip of the nose was 55 pixels, and I roughly estimated the the tip of the sting to be about 1185 pixels. The tip of the sting that is vertical is about 30 pixels tall, and the horizontal part before the lifted parachute boon section of the sting is about 1155 pixels.
(1175-100)/(1185-55)=1075/1130=.9513
.9513*21.9=20.8 meters.
3 pixel deviated
I measured as (1124-1080)*21.953=21.09
Here is the missing added
I will do it later, shall we finish this step to choose one of alternates
or abandon it?
Really Excellent?
Then do you think the green line was set along with the engine profile on the Su-27 in image by me, fairly enough or to be skewing?
Notice each lines in those images was set as single pixel.
Except you recognize, we move on……or shall we pause to check sth in detail?
The question isn’t whether it’s bigger or not, it’s how much bigger it is.
I was primarily interested in finding hq high resolution pictures of the J-20, Su-27, and J-10 to scale them based on nacelle size. Having a Su-27-J-10 comparison will provide some validity to the comparison, because if they don’t match up to the expected sizes we know there are errors to that method.
Here is a challenge

The left one is original photo, the right part was set red line on nozzle profile, if you recognize:
1) the diameter of outstretched nozzle on J-20 JUST is same as what on Su-27, then please move to 2)
2) the red line just match the nozzle profile exactly without bias.
then we move to next step to be continue.
In China that was be verified as a fake.
Problem is not HQ for Su-27 but J-20. So I used F-22 to substitute.
The key here is, if at least six AIM-120C5 or some missile sized like that to be arranged in weapon bay, the wingspan of J-20 wont be smaller than F-22 and its diameter of main wheel will be bigger either.
Um…the engine nacelles aren’t the same size in that picture…
Everything else is irrelevant, since they are not features the J-20 and Su-27 would share.
That’s what I get for guesstimating with an iphone. On the other hand, just reducing the weapons bay estimate down to 3.2 meters would yield a result of 20.4 meters. Higher resolution pics are probably desired in this case.

Although there is oblique angle, but the gap leaving from AIM-9’s head is almost same as its wingspan ~ 279mm and the gap being tail not counted. Remember there is fire brake at tail.
And you can also call this below engine match with LQ photo, but main wheel of J-20 seems to be smaller.
Not sure what your point is on the Su-47:confused:
There are several good youtube vids where the aircraft are in post stall or landing speed, and the Carnards and Flight Control System are workin over time stable the aircraft.. as they should.
That they produce extra drag, is not a big deal, the pilot has the throttle stick for that.
It is worth saying, that the Su-47 had exellent slow speed regime, certainly no worse than the Flanker.When the Su-47 regain speed the deflection are much lesser, just like every other Carnards fighter.
Where is the link? I had never seen Su-47 did any post stall maneuver…
Sorry for quoting my self..:D
But i’m on thin ice here..
If the T-50 are going at low speed and accelerate as fast as can be done up to say 1.2 Mach.
Could the LEVCONS degrade the performance regarding airflow/pressure into those intakes?
Yes.
I’m not talking about fully extended of course, but say half extended down.
The F-15 has some feature on the top of its intakes which regulate the airflow in high Mach.
My point is, could this LEVCON function the same way as the F-15 intakes?
No, In high mach number, the F-15 goes rely on ramp inside the inlet not that inlet frame.
Why? Because the engine fairings of the J-20 are massive compared to the Su-27 in the comparison pic where you made them look the same size? I’m curious to see what results you get when you rescale that picture to match engine fairings, since that is the One feature we know probably share the same dimensions. Afterall you tried to use the same argument for the J-10 comparison.
For the engine match, the J-20 could be 22 meters long as well as 21 meters, and I anounced that could be 1 meters deviation there, that is why I set the 21 meters as the lowest limit due to conservative side.
What was done by me as you could see, always based on not only one aspect but also other presumption.
In the LQ photo below, you can see not only engine nacelle match but also main wheel match and canopy match.
Therefor, something you denied, not to my methodology but LQ photo.
Instead of making assumptions about weapons bays (if we use the 3.3 meter sidebay assumption it comes to less than 20 meters) we finally have a valid feature comparison (and what happened to hq pictures? That was a rather low resolution picture used on the weapons bay scaling). Why aren’t you using it? Surely there is no absence of high quality profile images of the J-20 now?
Come to less than 20 meters?
Are you able to do math?
In the photo there clearly show 9.75 to 4.07 for the length of J-20 and 7.07 to 6.18 for the length of side weapon bay.
So (9.75-4.07)/(7.07-6.18)×3.3meter=?

An AIM-9X is 3.02m long, to leave 10-20cm from missile on head and tail, the side weapon bay for F-22 won’t shorter than 3.3meter. This can be proved by photo below.
The main weapon bay is around 4 meters long, you can easily make out how long at least the side weapon bay will be.
Here is J-20 weapon bay on side for your calculation
Here we presume the J-20 use AIM-9X as well, or you can insist PLA’s integrative capability could be greater than US so that the side weapon bay on J-20 will be significantly shorter than F-22’s.
This image was done by me if my memory works.
A LQ could provide a wrong direction but I have to say the length of J-20 is more closer to Su-27 rather than F-22,
There’s nothing logical about saying a result is wrong because “it doesn’t look right”. That intuitive assumption without objective reasoning can get things wrongs. On the other hand, we can say something about whether a method is right or wrong, though you would still have to provide reasons.
Does that “J10B vs J20” provide any objective aspect or just looks like wrong or right?
Here is an objective part:
See the yellow line is the position where nozzle to be convergence.![]()
To drag the J-10 down to see the nozzle from J-10B is too thick to be true![]()
yes you may say that nozzle is being outstretched, so I cut the nozzle to complete it![]()
Now you can see, it is still too large for the J-20.
This is the objective way to measure object objectively.