Su-57 Stealth Fighter: News #6

Sukhoi guys are lazy bastards that put no effort in the PAK-FA... can someone be more stupid than that?

UAC sent out a new tweet on the mfg of the su 57. The dedicated haters ,hacks and disinfo agents have yet to descend on it. But they will.

https://twitter.com/UAC_Russia_eng/status/1338426038762811394

Look at the hat of that guy! Absolutely not stealthy!

kvs wrote:These releases have a purpose.  They are to show the yanqui exceptionalists that Russian manufacturing processes are not inferior
to their own.   I am sure that some US MIC experts are looking over these.    Americans are stupid and need visual prompting.
News such as the one about Russia replacing the composites used for the MC-21 does not clock in their hubris addled brains.

"They don't build anything!" - Some clown with no scientific/engineering credentials, but instead a failed presidential legacy.

They were literally buying rocket engines from the gas station nation. It's interesting that they 'NEED' Russian rocket engines, and Russian expertise in creating The ISS...surely they could do it on their own without the need of the gas station nation with brain-drain and no industrial capital.

Backman wrote:UAC sent out a new tweet on the mfg of the su 57. The dedicated haters ,hacks and disinfo agents have yet to descend on it. But they will.

https://twitter.com/UAC_Russia_eng/status/1338426038762811394

Thy have already  

Backman wrote:

Linking full photos in all their 4096x4096 glory for all us lazy bastards out there:

Sorry the only reason why I brought up the other guy's response is if I wonder if this board has covered it before. https://qr.ae/pNwQUh I just need to make some updates later in the articles I have fun writing up about the aircraft.

LMFS wrote:Thanks for the link  

You are welcome  

LMFS wrote:It is quite striking that they simulate such AoAs with canard deflections that do not relate to real deployment of the control surfaces in actual current aircraft. After the onset of the maneuver, canards are kept at reduced AoA in order to help keep the airflow attached to the wing, not in the same angle as the wing. This very much affects the results of the simulations.

True to some extent!
Later on I will show why  

LMFS wrote:There was a study for the J-20 where they showed that canard + LERX had a synergistic effect improving the Cl of the plane, I think it was mainly due to vortex interaction. In that plane though, the canard in the same plane as the wing negatively effects lift during positive deflection.

True, we can see that canard/LERX combo in the case of Rafale, or Su-30SM gives very good results!

LMFS wrote:See above, the simulation is not realistic because LERX is fixed and works by creating vortexes while canards are mobile and they also keep airflow attached to the wing without the need to create draggy vortexes. Look this:

The second part is actually not correct, and the whole thing about canard deflection is not that simple.

Canards most definitely create vortices and they are also creating the downwash on the main wing. Depending on the canard placement, downwash from a canard is generally decreasing the wings lift, but the fact that the vortices are reattaching the airflow over the main wing at higher AoA [energizing the flow, and are also delaying the stall], is contributing to overall higher max Cl.
There are no such consideration regarding the downwash in the case of the LEVCON's.

Here is excellent video of the flow visualization and canard/wing interaction on the Su-30SM during BFM, look at 13:15 of the video:



We can see intensive canard vortex interaction with the main wing, and it seems that the Su-30SM canard acts like a "free floating" type, where the canard is most of the time close to 0 AoA in relation to incoming airflow at lower angles of attack. At higher AoA there is most probably different type of deflection.

Here is a very good paper on "Vortex Dynamics Study of the Canard Deflection Angles’ Influence on the Sukhoi Su-30-Like Model to Improve Stall Delays at High AoA": file:///C:/Users/Bojan/Downloads/aerospace-06-00012.pdf



Here we can see canard vortex/wing interaction at different AoA and different canard deflection angles.



Here we can see the Cl in relation to the AoA and canard deflection position.

It is very interesting to note that the Max Cl for the no canard deflection and different canard deflections is almost the same, but the difference in Cl as the AoA progresses above the 40 deg. is significant!

LMFS wrote:It is quite striking that they simulate such AoAs with canard deflections that do not relate to real deployment of the control surfaces in actual current aircraft. After the onset of the maneuver, canards are kept at reduced AoA in order to help keep the airflow attached to the wing, not in the same angle as the wing. This very much affects the results of the simulations.

Here is the general conclusions from the Su-30 study:

"From this study, it was found that the employment of canard will affect the aerodynamic character of fighter aircraft. From the results of flow visualization analysis and aerodynamic force analysis using water tunnels and CFD, it could be summarized that changes in the deflection angle of canard affect the formation of eddy nuclei and flow interactions that affect the lift force coefficient, vortex breakdown location, and pressure distribution that occurs. At low attack angles (<40°), the best conditions occur in standard configurations without changes in canard angle deflection. The use of canard deflection angles results in a lower CL value. Hence, at a low angle, it is not recommended to use canard deflection angle.
The addition of AoA value which is higher than 40° causes the standard configuration to experience a significant decrease in CL, and the location of the breakdown vortex will be at the end of the wing, and stalling will occur. The use of canard deflection will improve slower decreases in CL and maintain the presence of vortex cores. At very high AoA (>60°), the deflection angle of 30°–40° is still capable of producing CL and vortex nuclei. Hence, this shows that the configuration deflection
angle 30°–40° is able to delay the occurrence of stall up to an AoA of 80°, which is very necessary for maneuvering motions. The combination of effects from the fighter’s head configuration and canard deflection would make the vortex core curve, and vortex merging occurs, which causes a delay of the stall above the wing."

If we compare this simulated model with the real Su-30SM there is certain disparity in desired and real canard deflection for different flight conditions. The point of simulation was to find the best canard position in relation to the max lift generated, [which is also in direct connection to the delay of the stall point], but they didn't took the lift to drag ratio into consideration as well as the shift of the center of pressure that is in direct connection to the stability of the plane in the lateral axis, and that can be the reason for inconsistency with the real model.

Here is also one example where we don't have the canard deflection at relatively high AoA:



Both planes are demonstrating the slow speed pass and we can see that the Rafale is having LE flaps full extended, but the canards are in the neutral/fixed position [it's the same in the case of EF2000 for example]. In that configuration the plane is having the highest Cl for a given speed and AoA.
On the other hand, PAK FA is having LEVCON's deflected down for the best Cl for that flight condition.

LMFS wrote:The canards are in this case used as a LE "slat", with the advantage that the airflow is more energized than it would be with a LE flap. That is the reason why I think they are superior in terms of lift augmentation even to a LEVCON like that in the Su-57, but I cannot prove it conclusively.

At high AoA the LEVCON is reattaching the airflow to the upper surface [also creating more camber of the airfoil cross section], and at the same time it is producing very powerful vortices in synergy with the LERX, without negative effects of the downwash on the main wing. It can also be used for directional control at extreme AoA and has enough pitch down authority to put the nose of the plane down in controlled manner if the TVC is out of order. I also tend to believe that it is more efficient at supersonic flight conditions. In my opinion it is more versatile solution than the canard, especially if we account the RCS in to equation.

LMFS wrote:I cannot judge that, no one is saying neither of the planes is trying to yaw as fast as possible. The Su-35 is equipped with LE flaps over the length of the wing. I agree though that the airflow management of the Su-57 with mobile LEVCONS + small LERX over the fuselage should be far superior to that of the Su-35 with big fixed LERX only.

There is no doubt that the PAK FA is having faster yaw rates because I have watched almost all available videos and the conclusion is the same, and we can also deduce based on the TVC and aerodynamic surface deflection whether the pilot is giving max command inputs or not.
Here is also the word of the Sergey Bogdan on that part: "This is the most elementary thing that has already been implemented on the Su-30 and Su-35. The T-50 has more powerful engines, and in the future they will be even more powerful. It has more specific control surfaces that can create more moments, therefore, at high angles of attack, in super-maneuverability modes and in those situations where it is necessary to intensively maneuver, the aircraft behaves more optimally, more comfortably, steadily and controllably. In general, the T-50 from the point of view of controllability is already something qualitatively new."

LMFS wrote:Eurocanards are single tail planes and therefore their high AoA handling is not on par with that of other twin keel designs. I don't have an opinion about J-20, have not researched enough.

I have almost no doubt that the J-20 will have better high AoA characteristics than all Eurocanards!

@^PeregrineFalcon:

Thanks for the papers and sources, and sorry that I have not the time to replicate in kind.

PeregrineFalcon wrote:
The second part is actually not correct, and the whole thing about canard deflection is not that simple.

The "also" word is intentional in the wording above because I know the canard's tips create vortexes as any airfoil. I referred to the downwash effect from its upper face combined with the injection of air into the low pressure area formed above the wing, this prevents the wing stalling at high AoA.

Canards most definitely create vortices and they are also creating the downwash on the main wing. Depending on the canard placement, downwash from a canard is generally decreasing the wings lift, but the fact that the vortices are reattaching the airflow over the main wing at higher AoA [energizing the flow, and are also delaying the stall], is contributing to overall higher max Cl.
There are no such consideration regarding the downwash in the case of the LEVCON's.

Canards help deflect the airflow in front of the wing at high AoA, as LE flaps (LEVCONS in PAK-FA act mostly in that fashion) do. They have the advantage of air being fed through the slot reenergizing the boundary layer though.





I am not getting a clear comparison of LE flaps vs. slats, I saw a good picture some days before but I am not finding it anymore... the idea is that the canard has this function too. I am not sure the LEVCON in the Su-57 does not have a slot in built though, it may also be the case and it would in fact make much sense.

We can see intensive canard vortex interaction with the main wing, and it seems that the Su-30SM canard acts like a "free floating" type, where the canard is most of the time close to 0 AoA in relation to incoming airflow at lower angles of attack. At higher AoA there is most probably different type of deflection.

This is what I meant, the canard is used more as a conditioner of the flow over the wing than as a lifting device itself. ITtcan be different in Rafale and Eurofighter, I have observed more Russian designs to be honest, and besides the Flanker already has the tail for better authority than the flaps in the Eurocanards can provide, so it does not need the canards in the same way. This is the layout that I find more interesting, because it has always the ability to create lift where it is needed, be it for maneuver or trimming purposes.

Regarding the higher AoA, check the picture of the almost-crashing Su-33, the position of the canard is you have noticed almost at zero degrees with the airflow. This is what I have observed almost invariably in Sukhoi designs.

It is very interesting to note that the Max Cl for the no canard deflection and different canard deflections is almost the same, but the difference in Cl as the AoA progresses above the 40 deg. is significant!

Certainly, this is the effect I refer above. The wing bends the air by viscosity, so the higher the gradient, the bigger the chance for stall. The ideal device for creating big airflow deflections is the slotted flap that we see in airliners, where several planes of increasing deflection are connected with slots between them, that continuously inject airflow to the boundary layer.

The use of canard deflection angles results in a lower CL value. Hence, at a low angle, it is not recommended to use canard deflection angle.

Interestingly that is not what Sukhoi does.

If we compare this simulated model with the real Su-30SM there is certain disparity in desired and real canard deflection for different flight conditions. The point of simulation was to find the best canard position in relation to the max lift generated, [which is also in direct connection to the delay of the stall point], but they didn't took the lift to drag ratio into consideration as well as the shift of the center of pressure that is in direct connection to the stability of the plane in the lateral axis, and that can be the reason for inconsistency with the real model.

Yes makes sense. See my considerations above too, probably the Fanker was not designed with the canards in mind and it certainly can do without them, so the idea and scheduling behind its employment can be different from other canard designs.

Both planes are demonstrating the slow speed pass and we can see that the Rafale is having LE flaps full extended, but the canards are in the neutral/fixed position [it's the same in the case of EF2000 for example]. In that configuration the plane is having the highest Cl for a given speed and AoA.
On the other hand, PAK FA is having LEVCON's deflected down for the best Cl for that flight condition.

Interesting, I think I had seen some video of the Rafale and the canard had an AoA slightly lower than the wing. In any case, a delta wing like that is not very good to create lift at low speed so they maybe use the canard for that purpose rather than airflow conditioning like the Su-30.

At high AoA the LEVCON is reattaching the airflow to the upper surface [also creating more camber of the airfoil cross section], and at the same time it is producing very powerful vortices in synergy with the LERX, without negative effects of the downwash on the main wing. It can also be used for directional control at extreme AoA and has enough pitch down authority to put the nose of the plane down in controlled manner if the TVC is out of order. I also tend to believe that it is more efficient at supersonic flight conditions. In my opinion it is more versatile solution than the canard, especially if we account the RCS in to equation.

The "LEVCON" in the PAK-FA is a very sophisticated device that unites the functions of a canard, a LE flap and a LERX to some extent. I still see the advantage in the canard that I mentioned above, but other than that I agree.

There is no doubt that the PAK FA is having faster yaw rates because I have watched almost all available videos and the conclusion is the same, and we can also deduce based on the TVC and aerodynamic surface deflection whether the pilot is giving max command inputs or not.

I cannot say I have studied that in depth, I take your word for it.

Here is also the word of the Sergey Bogdan on that part: "This is the most elementary thing that has already been implemented on the Su-30 and Su-35. The T-50 has more powerful engines, and in the future they will be even more powerful. It has more specific control surfaces that can create more moments, therefore, at high angles of attack, in super-maneuverability modes and in those situations where it is necessary to intensively maneuver, the aircraft behaves more optimally, more comfortably, steadily and controllably. In general, the T-50 from the point of view of controllability is already something qualitatively new."

Nice quote, in line with what we see re. surface controls and general aero design. Some people think the only difference between Su-35 and 57 is that one is stealth and the other not, and that it is therefore a bad idea to substitute the older model with a newer, more expensive and maybe short lived design, since stealth can be defeated by new radar types. I cannot disagree more, the Su-57 is more advanced in every regard, from aero to systems to weapons bays etc., and it will show in the years to come.

LMFS wrote:Sukhoi guys are lazy bastards that put no effort in the PAK-FA... can someone be more stupid than that?

I feel like this forum should do like a multiple choice survey(sorry no all of the above option) as in what was the biggest military strategic mistakes Russia did with the following 3 choices.

A) Giving away Ufimtsev's Equation.

Which resulted in jingoistic chest thumpers telling how great their country is in stealth and how your aircraft is to match their expectations.

B) Selling Kholod Project and Kh-31 information

Which resulted in jingoistic chest thumpers saying much great their country is in air breathing missile technology than yours.

C) Selling Alaska.

Based on military build up in Europe, Russia could have responded back doing the same in Alaska which is still pretty close to the U.S.

Sadly I kept on persisting such users to speak their minds about the Su-57 here, but of course its a no for them. The fact that such users have so much other accounts on other forums but not this one just makes it more hilarious I do like yours and PeregrineFalcons contribution here on the Su-57.

A) nazi already tested stealth design. They had a flying wing before US started their programs or before soviet maths about stealth. Their work would have been used and the mathemarical models would have been found anyway.

B) kh-31 is just a ramjet missile. West already masters ramjet and could produce its own if they really want. Chinese is copying everything and also came with its own copy of kh-31.

C) Alaska is not suitable for human life. US can't populate it enough. They will become Africa vefore Alaska becomes a real asest for them.

Tests of new Su-57 weapons will be completed in 2021 - First Deputy Chairman of the Board of the Military-Industrial Complex of the Russian Federation

Moscow. December 16. Interfax - Tests of the Su-57 aircraft armament complex, including the intra-fuselage, will end in 2021, Andrei Yelchaninov, First Deputy Chairman of the Board of the Russian Military-Industrial Commission (MIC), told Interfax.

"The peculiarity of the Su-57 is that it carries not only weapons that are already used by other types of aircraft (MiG-29, Su-30SM, Su-34), but also new types of weapons that will be used from the inside of the fuselage space. it is planned to be completed in 2021 as part of the aviation weapons complex, "Yelchaninov said.

He stressed that these are completely new types of weapons, which are created from scratch, including using new guidance principles.

According to him, the delivery of the first serial Su-57 to the military is expected as planned - by the end of December.

"There is complete confidence that the aircraft in the form that is being transferred to the troops will complete state tests in 2021, all technical problems have been resolved," Yelchaninov said, adding that 10 prototypes of the Su-57 have already completed over 4.2 thousand test flights.

https://www.militarynews.ru/story.asp?rid=1&nid=543325&lang=RU

[size=16]It is possible that a two-seater version of this aircraft will be in demand for export. We are able to create it: now this need is being rethought by both our Defense Ministry and potential customers.[/size]

https://www.militarynews.ru/story.asp?rid=2&nid=543339&lang=RU

dino00 wrote:[size=16]It is possible that a two-seater version of this aircraft will be in demand for export. We are able to create it: now this need is being rethought by both our Defense Ministry and potential customers.[/size]

https://www.militarynews.ru/story.asp?rid=2&nid=543339&lang=RU

Iran and India love twin seaters. That will easily be 200 su-57 only. Then smaller countries could buy 6-12 single seaters.

Export potential IMO is about 300 jets. With a unit cost of 80-90 for export version they will make 30 billion $ only for the jet. You can multiply by 2-3 for the servicing during their life. The program will bring them almost 100 billion only for export and it costed no more than 15 billion.

India could have had their own version if they invested 6 billion but now they will beg for su-57 and pay hard price. But it will still be inferior to Rafale or f-18.

^ Enlighten us on how the su 57E will be inferior to F-18's and Rafales.

Backman wrote:^ Enlighten us on how the su 57 will be inferior to F-18's and Rafales.

I was talking bout price.

dino00 wrote:
"The peculiarity of the Su-57 is that it carries not only weapons that are already used by other types of aircraft (MiG-29, Su-30SM, Su-34), but also new types of weapons that will be used from the inside of the fuselage space. it is planned to be completed in 2021 as part of the aviation weapons complex, "Yelchaninov said.

He stressed that these are completely new types of weapons, which are created from scratch, including using new guidance principles

This means that the Russians could keep the new weapons, whatever they might be, hidden behind closed doors if they wanted. Thus preventing anyone from knowing even what they look like for many years.

That would upset Western analysts

dino00 wrote:Tests of new Su-57 weapons will be completed in 2021 - First Deputy Chairman of the Board of the Military-Industrial Complex of the Russian Federation

Moscow. December 16. Interfax - Tests of the Su-57 aircraft armament complex, including the intra-fuselage, will end in 2021, Andrei Yelchaninov, First Deputy Chairman of the Board of the Russian Military-Industrial Commission (MIC), told Interfax.

"The peculiarity of the Su-57 is that it carries not only weapons that are already used by other types of aircraft (MiG-29, Su-30SM, Su-34), but also new types of weapons that will be used from the inside of the fuselage space. it is planned to be completed in 2021 as part of the aviation weapons complex, "Yelchaninov said.

He stressed that these are completely new types of weapons, which are created from scratch, including using new guidance principles.

According to him, the delivery of the first serial Su-57 to the military is expected as planned - by the end of December.

"There is complete confidence that the aircraft in the form that is being transferred to the troops will complete state tests in 2021, all technical problems have been resolved," Yelchaninov said, adding that 10 prototypes of the Su-57 have already completed over 4.2 thousand test flights.

https://www.militarynews.ru/story.asp?rid=1&nid=543325&lang=RU

"4.2 thousand test flights." The Drive is shitting their diapers right now, and according to them the Su-57 is a cancelled failed project that won't be mass produced. Fun Fact: The Su-57/PAK-FA project didn't even have 1/100th the problems seen in the F-35 project, and it's development cost was a miniscule minute fraction of the costs of the F-35 "Avoid Lightning" lmao!

There is an artistic rendering floating around of what a two seat su-57 might look like. It's breddy gud. I'll try and get it. It would actually be a great idea as the person in the back can act as a quasi awacs for single seat su 57 and other fighters.

I thought those new weapons were to be tested with the new avionics and engines 2022-2024, not complaining that the end of 2021 those weapons will be ready. However it would be nice if by this Christmas they give some details on those new weapons

A dual seater Su-57 could be used to train pilots and as a command aircraft for a drone swarm.
It could also be used for the fighter bomber role.

Often they keep things hidden anyway... in the 1980s they had the R-27ER and R-27R which were passive radar homing missiles.

The idea is that you carry a couple of them and some standard R-27EP SARH missiles... if you get into a duel with a Sparrow armed F-15 they will illuminate your aircraft after getting a lock and then launch their Sparrow SARH missile.

You mix them. The ER and R are SARH. The P is passive homing.

With modern track while scan and narrow beams it would be very hard to use the P. But it can still be very good against air defence systems with an upgrade. Better than using the more expensive kh-31.