A rather vague requirement, given that the compilers of the tender document will not have had any reliable information on the RCS of the F-22.

Second-hand information on RCS values is all we currently have, and all that is likely to be in the public domain for the foreseeable future. The limited information I have on the RCS of the F-22 was given to me verbally by a programme official; I was not shown any documentary material.

Of course Russia will have one or more RCS ranges. But I wonder whether an undisclosed T-50 airframe with full stealth capability has been built and delivered to a Russian RCS range, and is being kept fully-representative of the planned production configuration. If that has not happened, then the only sources of T-50 RCS data currently available to the customer will be from mathematical modelling and the results from tests conducted on (full-scale?) models.

A rather vague requirement, given that the compilers of the tender document will not have had any reliable information on the RCS of the F-22.

From what I’ve seen of the tender, the comparison to the F 22 was always a secondary comment. It first says stealth. Simply stealth.

But I wonder whether an undisclosed T-50 airframe with full stealth capability has been built and delivered to a Russian RCS range,

So we can add you to the people who don’t believe that the tender has currently been filled in good faith ?

This would be impossible.
The russian military has a stealth proving ground where radar calibration against aircraft is done. Also at the russian airforce proving ground it will come against su-35 and su-30sm radars, this will show up.
Also India is also covering this aspect and wants stealth as a priority also.

Indeed. But that is what is continually being implied throughout the thread by stealth absolutists.

Here is a sampling of that just in the last few pages..

but only a few teams are implementing actual “stealth” levels of RCS reduction.

T-50 still has decades to go to catch up to 1980’s level stealth.

PAK FAs RCS would be extremely high from this aspect.
[I]

The Russians may well know what’s needed to create a proper stealth aircraft, but [/I]

Either Sukhoi has planned to incorporate RCS reduction and hiding the compressor on a new IGV section, a separate section of variable vanes set in front of the fan (that we haven’t seen yet), or both.

Bacon

not sure where all the j-20 thread goes but might as well start a new one for the new year!
http://www.businessinsider.com/the-real-purpose-behind-chinas-mysterious-j-20-combat-jet-2017-1?r=UK&IR=T&IR=T

A senior scientist at Lockheed Martin told Business Insider that the Chinese made serious missteps when trying to integrate stealth into the J-20.

Did anyone expect a raving review from a Lockheed employee ?

Somebody was saying that these drawings are to scale and that they prove that the Raptor has a smaller frontal cross section. I think these pics prove the opposite.

So you seriously believe it will be entering service with those immense bays installed but inoperative? Features which induce design compromises that permeate the entire structural and aerodynamic configuration? Sorry, but that’s not credible in the slightest. That’s about the same as making the F-35A and -C fly around with the B-model lift-fan.

Possible, and entirely sensible if that fits the requirements of the Russian MoD – no point in spending money on tit-for-tats if there is no gain from doing so. And what would be wrong with that? Apart from the fact that it does not fit the popular narrative that Russia intends to take over the world by force, of course.

That is only possible if the Russian federation was just bluffing when it mandated stealth in the 5th gen tender and also mandated comparable stealth to the American F 22 Raptor. Either that or Sukhoi is lying about fulfilling the requirement of the tender. Or they are both in on it and bluffing to the world that the aircraft is stealth.

Because long range missiles are using radar seekers is reason why radar stealth is still imperative.

Lockheed approch with F-117? Exposed optics? Nope.

Hidden FLIR when there isn’t need for it. Back side have thick RAM to reduce ball RCS as possible as it can done.
Guess what stealth aircraft use same approach as F-117?

One of the original Raptor tech demonstrators had one.

Besides. This is a red herring. Sukhoi could easily make a deep strike variant with stuff like this shaved off. 2D exhaust could be done too. Everything could be added to a veriant to satisfy the stealth absolutists.

There has been talk of a shrouding system for the back of the engine that could go on and off on demand.

(a stealth absolutist is someone who questions the stealth designation of an aircraft who’s tender mandated stealth)

The Raptor is taller because its front wheel is taller ( which is the reason why when they are on the ground, T-50 nose points down, while F-22 nose doesn’t), and F-22 also has taller vertical stabilizer. However, the frontal cross section of PAK-FA is still bigger because it need the space to accomodate very big AG weapon which is the KH-58, it also has higher fuel fraction than F-22.If you want to know which one is bigger, just put their cutaways picture on the same scale with correct wing span.

There is still no hard data posted yet. None. And the bit of data we do have (height) shows that the Pak Fa is smaller. I don’t even know where Wikipedia is measuring the height. Just eyeballing it, the Pak Fa looks smaller too.

And it should be noted that the Pak Fa is shorter in height and bigger in wing coverage than the Raptor. But the YF 23 is even shorter than the Pak Fa and even bigger wing coverage too.

PAK-FA is still bigger because it need the space to accomodate very big AG weapon which is the KH-58, it also has higher fuel fraction than F-22.

The Raptor has to accommodate full size inward pointing S ducts.