Su-57 Stealth Fighter: News #8

What's the purpose of vertical stabilizers and why do future gens propose removing them?

thegopnik wrote:What's the purpose of vertical stabilizers and why do future gens propose removing them?

Because they are looking for troubles.
In the sense that they keep on over emphasizing the Stealth component of the whole complex and so they fell obliged to add a major portion of it in the design of their new planes, in this case eliminating totally the tails and above all rudders and trying to govern the plane just by use thrust vectoring.
So, they are making things much more difficult for themselves, adding a mostly unnecessary complication to what could instead by using a more evolutionary and incremental approach.
We know now thank to the comparison between the Su-35S and MiG-29OVT that 3D nozzles are not convenient in a two engined planes compared to 2,5 ones as they couldn't allow a sustained horizontal turn just by using gas flow diversion, so if someone want to lose time and money: their problems.

ALAMO wrote:It is only because ugly Russkie copied it before creation.
Like supa dupa missiles.
You should know it!

Konkordskii all over again!

Just like the MiG-25 is a clear copy of the F-15. 

Could someone post the advantages of having variable intake ramps vs a DSI

Mir wrote:@Gomit21

I see you are struggling to get some answers. As far as the canted engine goes...imagine viewing a twin engine Sukhoi fighter from the rear. Now you fit each engine with a 2D nozzle that can move up and down. Then you take the left engine's 2D nozzle and mount it in the 10 o'clock position in order for it to move at an angle instead of up and down. You then do the same with the 2D nozzle on the engine to the right, but you mount the nozzle in the 2 o'clock position.

The result is you get two axis-symetrical 2D vectoring nozzles (TVN) that gives you full 3D thrust vectoring control (TVC). This simple yet genius concept was the brainchild of the then General (Chief) Designer of the Sukhoi OKB, Mikhail Simonov.

Thanks for addressing the question.  I figured that was the case by using the term "canted" to describe the angle of the nozzles' movement (10 o'clock & 2'o'clock respectively) and not the 'installed' position.

I was always under the impression that the term "canted" referred to the installed angle of the vertical stabilizers only.  For example the Su-57, F/A-18, F-35, F-22 all have "canted" tail fins (stabilizers) whereas aircraft like the Su-27, Su-35, F-14 & F-15 all have vertical stabilizers that are not angled or "canted".  

So to me, the term "canted" was the fixed installation angle of those surfaces whether they were all-movable or fixed with movable control surfaces within (rudders).  

Even the engines and the way they're installed on the Su-57 are slightly angled to deflect outwards when viewed from the top (or from the bottom) of the aircraft and that is what I thought the term "canted" nozzles might've been referring to.  But it wasn't as you explained and as I went back and read the discussion again and saw that it referred to the 2D TVC movement axis.

And that axis as you showed it and as Peregrine Falcon described it is actually simply the 2D TVC nozzles rotated slightly (to 30 deg?) so they operate from 10 o'clock & 2 o'clock respectively.  Once they rotate differentially, then you get that ("quazi-3D TVC effect) which makes perfect sense.

Many people assume that tricky rotation used in differential modes is a full-fledged 3D-TVC nozzle when that isn't the case.  It does give it the impression that it is which is what makes it genius.  


Good to know these little details which are pretty important so we're on the same page with any future discussions.

thegopnik wrote:What's the purpose of vertical stabilizers and why do future gens propose removing them?

We had an extensive discussion on exactly this interesting concept on another forum a few years ago.

The purpose of V-stabs (or rudders) is mainly to control the yaw movement of the aircraft, but with the advent of the need to be a stealthy platform, having vertical and horizontal stabilizers increases the aircraft's RCS, even with angled V-stabs.  So why not eliminate them and use "V-tail" planes which then combine the duties of both, the vertical and horizontal stabilizers while getting rid of V-stabs at the same time.

This was already proven to be effective in the reduction of an aircraft's RCS with the development of the YF-117 and especially the YF-23.  And now we're seeing that feature in the development of the Su-75 Checkmate.

You can see the angle of the V-tails (also known as 'ruddervators' is much steeper than the angled V-stabs that are paired with H-stabs.  They're almost at 45 degrees (right in the middle of vertical & horizontal axis) of conventional H-stabs & V-stabs combined.



From the top view, they almost look like they're horizontal stabilizers with that extreme canted angle.



The Checkmate's ruddervators don't seem to be as steeply angled as the YF-23's. We'll have to keep an eye on its development and if they change that angle or keep it the way it is.

I dont know that i wrote here, maybe on another military forum, Serbian one, that next gen of any western aircraft will be copy of Su57. Why?

Because it have everything that this next gen aircraft needed. Small RCS, great avionics and radars (360° coverage), great manueverability. Russians made not 5th gen olane but probably 6gen....nd we see on this pictures of french new plane it has lot of similarity of Su57 and probably will have it even more in future...as will have new american next gen plane lot of similarity of Su57...

Su57 is next step of revolution not evolution, its revolution of combat multirole planes...

Serbian forums are no place to look for accurate information on anything

Yeah, but they will still rubbish the original... even when they copy.

The AK is inaccurate, the BMP has thin armour, smoothbore main tank guns are inaccurate, etc etc.

Except those are lies.

The BMP-1 had better armour than the M-113, the AK is not inaccurate... it is no sniper rifle, but at the ranges it is designed to be used you can reliably hit the target every time, and of course all the main main battle tank gun rounds... APFSDS and HEAT FS are both fin stabilised so the rifling of the main tank gun barrel does not effect their accuracy at all. Rifling actually slows them down and reduces their velocity potential.

PapaDragon wrote:
Serbian forums are no place to look for accurate information on anything

Really why is that, because on one good one we have lot of members on that forume are man of profetion military one, and they have lot of knowlage about military, about planes, tanks, artilery systems...so you say they do not know what they talking about?!

galicije83 wrote:

PapaDragon wrote:
Serbian forums are no place to look for accurate information on anything

Really why is that, because on one good one we have lot of members on that forume are man of profetion military one, and they have lot of knowlage about military, about planes, tanks, artilery systems...so you say they do not know what they talking about?!

Serbian forums are one giant collection of Karls Haushofers

Half of them are Russian fanboys other half are Western fanboys and all of them are talking out of their asses

For every accurate information they accidentally utter they will drop 50 epic bullshits

But if you like listening to bunch of Serbian morons whine, bitch and moan 24/7 about anything and everything because "they have knowledge and experience" (in their words) then Serbian forums are definitely place to go

Su-57 air launched recon and attack Drone. It can either be radio commanded or make decisions on its own via neural networks. At this point this thing is a 5+ gen aircraft.

I feel like I have more proof that the newer modernized Su-57 will have photonic radars since no one questioned this information here before. https://tass.com/defense/1323823
So new batch of aircrafts by end of this year will have 2nd stage engines(according to dec 2023 tass source) while the batch at the end of 2025 will have the new engines but also newer cockpits and newer avionics.(based on aug 2021 tass source)

They showed the Su-57 export with the original byelka radar with 200km for 1m2 targets.
But they have also revealed information that they have made 300km air to air missiles specifically for the Su-57.

The compatibility of both of these ranges cannot be met unless there is a newer powerful radar. Even if they got GaN modules you would still not get a 1m2 at 300km range and a Niip 2018 or 2019 source said they did not have the necessary production line to give GaN modules to Su-57s. The aircraft was specifically designed to have as much situational awareness as possible and designed to deal with other stealth aircraft according to its makers. If they gave the F-22 a 0.4m2 ballpark before, using the narrow beam technique to get that at 300kms might not work and leave huge blind spots if there were multiple aerial targets coming. With the PIC production starting somewhere this year it might be achievable to give photonic radars by the end of 2025 for the new batch of Su-57s.

Overall it is a good thing that russia had the foresight and started developing Radio photonic integrated circuits and radars as soon as possible, because that is pretty much the future