Come on ... each modern fighter can climb vertically. the question is only for how long.
I really don't know why You again and again bring up this video. It shows the J-20 climbing ... YES, but since the one who took these images is also moving You cannot disclose how long and even more since the J-20 is so small if the AB is not engaged during this climb.
In fact - and I know I will get my bashings for that again - it is nothing spectacular, simply lame even more to admit.
Deino
You still don't understanding the significance of start climbing vertically at slow speed, without slowing down at the top, and not using afterburner to do that.
It shows the Dry Thrust to Weight Ratio is > 1. That is the Dry Thrust itself is greater than the weight of the aircraft.
"Underpowered", it is not. J-20 using WS-10, it is not.
"it is nothing spectacular" To you, it isn't.
An Olympic powerlifter usually makes an EXPLOSIVE jerk to lift the heavy barbell over his head.
If someone is able to lift the same weight SLOWLY overhead his from the ground.
Who has more strength?
And here I'm simply not sure: this video-clip is too small, too blurred and too brief to be sure that no AB are used and again far from spectacular !
There are many J-20 video clips on youtube. They are ALL showing J-20 don't need to turn on the afterburner to make those agile turns and moves.
Able to NOT using the Afterburner is not the same as MUST using the afterburners to make same moves. It means a world of difference in Dry Thrust.
And here I'm simply not sure: this video-clip is too small, too blurred and too brief to be sure that no AB are used and again far from spectacular !
"far from spectacular" Then look at other youtube videos. NO AB were ever used. From my experience.
You haven't grasped the significance of climbing vertically w/o AB for a large aircraft means. It means J-20's engine has a freaking large thrust, larger than F-22's, larger than T50's. "Underpowered", it is NOT. Using WS-10, or AL-41F, it is NOT.
The F-22 crazy climbing footage is also small, but you can still see something like this.
View attachment 364208
J-20: without two shock diamonds = without afterburner on both engines
F-22: with two shock diamonds = with afterburner on both engines
The point we need to zero in is whether a plane need to use AB to do the similar moves or not. If it is spectacular but need to turned on AB to do that, the plane could only do that for a few minutes before the engine overheat or run out fuel.
It also leaves a very distinctive heat signature with very hot and very exhaust flame shooting out of the nozzle, leaving the plane very easy to spot, very far away. Not good to dodge a modern heat seeking missile.