Su-57 Stealth Fighter: News #8

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

Supa dupa missile don't lie buddy!

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.

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.

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