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    Su-57 Stealth Fighter: News #8

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    Swgman_BK


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    Post  Swgman_BK Fri Jan 12, 2024 3:40 pm

    Does anyone have pictures of service Su57 without the rivets and exposed screws. The internet is flooded with Su57 prototypes that dont have RAM installed.
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    Post  Mir Fri Jan 12, 2024 3:43 pm

    @PeregrineFalcon

    This is just my opinion but the "flat spin" performed by the then non-TVC Su-37 is not an actual flat spin. The F-22 can also perform that particular maneuver coming out of a tail slide or/and a J-turn as well - claiming to be a controlled flat spin.  A true controlled flat spin is around the aircraft's own axis. The Su-37 - in this case - does not rotate around it's own center of gravity axis (around 2:40). The axis is somewhere in front of the nose so the turn is more like an extended spiral and therefor also slower as you've mentioned.

    Here you can see a true controlled flat spin around the aircraft's own center of gravity axis. I'm pretty sure from what you posted, that you will understand what I'm saying - or trying to say.  Laughing



    As far as Combat Approve goes they normally do not to show highly classified information - which is normal. Not even going to talk about any other video footage we get to see. Anyway I'm pretty sure that most of the AL-51 is still top secret so I would guess (pretty sure actually) that the 3D nozzle showed there is not from the latest engine but rather from the AL-41 or maybe even an earlier AL-31 engine?

    The picture I have shown from the much older AL-31FP (which all these engines are derived from) clearly shows the left engine not only canted but with the nozzle slightly tucked in under the stinger. In my opinion this would be impossible for a "2D only" canted engine. Just saying.  Smile

    Su-57 Stealth Fighter: News #8 - Page 38 Su-30-12

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    Belisarius


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    Post  Belisarius Fri Jan 12, 2024 5:57 pm

    Swgman_BK wrote:The internet is flooded with Su57 prototypes that dont have RAM installed.

    And why would the Russians go to the trouble of constantly keeping the surface of the Su-57 PROTOTYPE always clean and smooth with no visible rivets or screws?

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    Post  Swgman_BK Fri Jan 12, 2024 6:04 pm

    And why would the Russians go to the trouble of constantly keeping the surface of the Su-57 PROTOTYPE always clean and smooth with no visible rivets or screws? wrote:

    I just wanted pics of the Su57 in its service state with RAM and everything installed. Not the Airshow prototypes..
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    Post  lancelot Fri Jan 12, 2024 6:05 pm

    Swgman_BK wrote:I just wanted pics of the Su57 in its service state with RAM and everything installed. Not the Airshow prototypes..
    Look for pictures of the T-50-11 prototype. It should have the same finish as the production versions.
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    Post  GarryB Fri Jan 12, 2024 7:18 pm


    Anyway I see in your post above you completely ignore the controlled flat spin performed by the Su-57. A maneuver that can only be accomplished by 3DTVC's.

    Any aircraft can enter a flat spin... existing should be possible with only 2D TVC.

    I have mentioned before that the sole Mig-29OVT is one of my favorite Migs and I am well aware of what it can do.

    The manouver performance of the Flankers and Su-57 is astounding but I would like to see actual 3D nozzle movement before taking someones word.

    So it's not only canted but the nozzles can also move a bit from side to side as well. In your parlance it should make it 3.5D then?

    If it can move up and down there would be no benefit to canting it... that would just complicate things for the flight control system.

    You can have for example 15 deg. of metal angle deflection (nozzle deflection), but the plume deflection is always less than metal deflection.

    The amount of rotational force a 15 degree deflection of thrust can create is actually enormous and can throw a 20+ ton plane around the sky at near zero flight speeds where conventional control surfaces do nothing at all.

    Would also add that while they do add weight and complexity to an aircraft that even for a bomber being able to optimise its thrust line and create an artificial angle of attack to maximise lift and reduce drag or even reduce forward RCS then TVC might even be useful on a flying wing design.

    Theoretically a flying wing could be designed to fly supersonic with TVC being able to counteract the huge shift in cg during acceleration from subsonic to transsonic and supersonic flight speeds... in fact a conventional swept wing design with the outer 20% of the wing being forward swept so spanwise flow would gather at the position 20% distance from the wing tips and the wingtips would not create enormous vortex drag flows would actually be rather interesting in aerodynamic terms for a supersonic flying wing design... of course the thing wing and body sections of the flying wing would need to be rather thin to reach supersonic speeds which would render it useless as a strategic bomber or missile carrier.
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    Post  GarryB Fri Jan 12, 2024 7:29 pm

    As far as Combat Approve goes they normally do not to show highly classified information - which is normal. Not even going to talk about any other video footage we get to see. Anyway I'm pretty sure that most of the AL-51 is still top secret so I would guess (pretty sure actually) that the 3D nozzle showed there is not from the latest engine but rather from the AL-41 or maybe even an earlier AL-31 engine?

    To be clear I am not saying Saturn can't make 3D TVC engines.... I am suggesting they have had testing with the MiG-29OVT and probably their own studies and decided that 2D canted nozzles with an advanced flight control system would make more sense.

    When they first started making the Su-35 they decided originally to use canard foreplanes to improve manouver performance and lift at takeoff etc etc... but after developing new flight control systems and software they realised the canard foreplanes were really only useful in takeoff and landings so they saved money and space and weight and removed them from the design. The extra weight and drag reduces the Su-30s top speed, but its advantages during takeoff and landing means the Su-33 has canards too.

    If you can get what you want with something that is lighter simpler and cheaper then why not... I have no problems with that...
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    Post  Mir Fri Jan 12, 2024 7:35 pm

    Belisarius wrote:
    And why would the Russians go to the trouble of constantly keeping the surface of the Su-57 PROTOTYPE always clean and smooth with no visible rivets or screws?

    He is just trolling.

    Su-57 Stealth Fighter: News #8 - Page 38 Troll-10

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    Post  Mir Fri Jan 12, 2024 8:07 pm

    GarryB wrote:Any aircraft can enter a flat spin...

    Very true but very few can do a controlled flat spin around it's own axis.

    GarryB wrote:If it can move up and down there would be no benefit to canting it... that would just complicate things for the flight control system.

    Shocked Shocked Shocked
    Clearly you have not been paying attention as I have explained it several times but perhaps you should ask Sukhoi for an explanation as to why they've elected to cant the Sukhoi's engines? Laughing

    But for good measure here it is once again...
    "the canting allows roll and yaw moments by vectoring each nozzle differentially, thus enabling the aircraft to produce thrust vectoring moments about all three aircraft axes, pitch, yaw and roll."

    This is what is known as "axis-symetrical" vectoring nozzles.

    It seems to be working great as there are literally hundreds of Sukhois with TVC's in service dunno

    GarryB wrote:When they first started making the Su-35 they decided originally to use canard foreplanes to improve manouver performance and lift at takeoff etc etc.

    When you say Su-35 you obviously meant Su-27M which had the canards?
    None of the Su-27M development aircraft had TVC's except the T10M-11 (the last prototype) which was re-designated as Su-37.
    It was mainly due to the introduction of TVC's and the digital FBW controls that they decided to remove the canards in the subsequent Su-35 developments. But then again it was brought back with the advent of the Su-30MKI/SM with TVC's and digital FBW.

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    Post  GarryB Sat Jan 13, 2024 6:00 am

    Clearly you have not been paying attention as I have explained it several times but perhaps you should ask Sukhoi for an explanation as to why they've elected to cant the Sukhoi's engines? Laughing

    Sorry, I didn't mean that, what I was trying to say was:

    If it can move up and down and left and right there would be no benefit to canting it... that would just complicate things for the flight control system.

    In other words if they used 3D TVC engines there would be no benefit to canting the engines... they cant the engines because they are 2D TVC engines.

    This saves complication and cost and weight and probably simplifies maintenance yet gives most of the main benefits of 3D TVC engines.

    I think it is clever.

    Being cheap and getting expensive performance from cheap... how Russian... or should I say how unAmerican.


    When you say Su-35 you obviously meant Su-27M which had the canards?

    No, The second attempt they were making a super manouvering super Flanker, but by then they had already realised that with canted TVC engines and the advanced flight control system that canards are just extra weight and extra drag and extra cost, so the Su-35... the one that entered serial production... doesn't have a Canard foreplane.

    Interestingly the Su-57 has something that acts like one but without the negative properties and a few new ones like hiding the engine intake when deflected downwards...

    But then again it was brought back with the advent of the Su-30MKI/SM with TVC's and digital FBW.

    My understanding is that this was because they could be used to reduce buffeting at low altitude at high speed on strike missions... which is also why the Su-34 had Canards too.

    The Su-35 is more intended to fly high and dominate than sneak around at low altitude at high speed.
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    Post  Mir Sat Jan 13, 2024 6:55 pm

    GarryB wrote:When they first started making the Su-35 they decided originally to use canard foreplanes to improve manouver performance

    Mir wrote:When you say Su-35 you obviously meant Su-27M which had the canards?

    GarryB wrote:No

    The Su-35 series started with the Su-27M development during Soviet times. The canards were implemented on the Su-27M mainly due to the extra weight of the N011 radar at the front of the aircraft, but the aerodynamic plusses were quickly discovered as well. The Su-27M was just about to enter full scale production when the Soviet Union collapsed. In 1992 Sukhoi re-designated the aircraft as the Su-35. In total, two prototypes, nine flying pre-production aircraft and three production aircraft. The production aircraft were delivered in 1996 to the Russian Air Force for weapons testing, but they were later transferred to the Russian Knights.

    One Su-27M was turned into a TVC development aircraft and was also eagerly demonstrated at airshows - the Su-37.

    Only in 2003 did Sukhoi attempt a second time at a Su-35 to serve as an interim aircraft whilst developing the PAK FA. This aircraft was the T-10BM or the Su-35BM. This aircraft had no canards but was fitted with TVC's. The main reason for deleting the canards was a substantial weight reduction in the nose radar due to technical advances. This shifted the centre of gravity of an aircraft more to the rear. The TVC's also played a crucial role in the deletion of the canards.

    Thus the canards were removed from the Su-35 design with the second attempt at a Su-35 - the Su-35BM.

    One Su-35UB trainer was also built but it is very similar to the Su-30SM with canards and also fitted with the older AL-31FP engines.

    Much of the technical problems that were experienced with the Su-27M were eradicated in the Su-35BM and the new engines allowed it to supercruise. One static and three flyable prototypes were built (one crashed). The Mig-35BM was used as development aircraft for the final Su-35 version - the production Su-35S with no canards.

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    Stealthflanker
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    Post  Stealthflanker Sun Jan 14, 2024 12:52 am

    Swgman_BK wrote:Does anyone have pictures of service Su57 without the rivets and exposed screws. The internet is flooded with Su57 prototypes that dont have RAM installed.

    It's always in Youtube. The assembly of the serial aircraft.



    You can see the different stages of assembly.

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    Post  PeregrineFalcon Sun Jan 14, 2024 7:36 am

    Mir wrote:@PeregrineFalcon

    This is just my opinion but the "flat spin" performed by the then non-TVC Su-37 is not an actual flat spin. The F-22 can also perform that particular maneuver coming out of a tail slide or/and a J-turn as well - claiming to be a controlled flat spin.  A true controlled flat spin is around the aircraft's own axis. The Su-37 - in this case - does not rotate around it's own center of gravity axis (around 2:40). The axis is somewhere in front of the nose so the turn is more like an extended spiral and therefor also slower as you've mentioned.

    Here you can see a true controlled flat spin around the aircraft's own center of gravity axis. I'm pretty sure from what you posted, that you will understand what I'm saying - or trying to say.  Laughing


    If you want to make your own definition of the flat spin that's fine, but both, non-TVC Su-37 and F-22 can do it under perfect control. Only difference compared to the Sukhoi fighters with canted 2D TVC is in the rotation speed, turn radius and AoA. It is true that planes such as Su-30SM, Su-35S or Su-57 can make it more around of their center of gravity and at much faster rate, but that was generally the point of the canted 2D TVC nozzles.



    As far as Combat Approve goes they normally do not to show highly classified information - which is normal. Not even going to talk about any other video footage we get to see. Anyway I'm pretty sure that most of the AL-51 is still top secret so I would guess (pretty sure actually) that the 3D nozzle showed there is not from the latest engine but rather from the AL-41 or maybe even an earlier AL-31 engine?   The picture I have shown from the much older AL-31FP (which all these engines are derived from) clearly shows the left engine not only canted but with the nozzle slightly tucked in under the stinger. In my opinion this would be impossible for a "2D only" canted engine. Just saying.  Smile   Su-57 Stealth Fighter: News #8 - Page 38 Su-30-12 wrote:

    Here is the Su-37 2D TVC nozzle that is not canted:

    Su-57 Stealth Fighter: News #8 - Page 38 D5cs2n10

    Here is the Su-35S 2D TVC nozzle that is canted:

    Su-57 Stealth Fighter: News #8 - Page 38 13937810

    They have simply rotated the nozzles by approximately 30 deg, and that is also the reason nozzles are tucked under the sting when they are in downward position.

    Here are differential deflection positions:

    Su-57 Stealth Fighter: News #8 - Page 38 Main-qimg-3597cfb9e119ff8275b82f8d27e8ae81-pjlq

    The nozzles can only go up and down, but with differential deflection you get the quasi 3D TVC effect. We can see that the nozzles in differential deflection are pointed in the same direction, but the one is pushing up, and the other is pushing down. For that reason you create both, the roll and yaw motion at the same time, and like I said, planes FCS is using aerodynamic surfaces to isolate the wanted vector by counteracting unwanted vector. Very simple and effective solution!

    Here is the AL-31FP nozzle:

    Su-57 Stealth Fighter: News #8 - Page 38 Unname10

    We can see two actuators that are pushing/rotating the whole nozzle up and down around the hinge. You can't have 3D TVC with that mechanical arrangement, it is simply not possible!

    Here is the Izd.30 nozzle looked from above:

    Su-57 Stealth Fighter: News #8 - Page 38 23472395_1598000276944688_5873089950441172557_n.jpg?_nc_cat=103&ccb=1-7&_nc_sid=c2f564&_nc_ohc=QW2KAlPj0K4AX_TCjLA&_nc_ht=scontent.fbeg4-1

    On the left and right we can see the same actuators, and the same ring sealant with holes that is present on the AL-31FP, AL-41F-1S and AL-41F-1.

    Here are true 3D TVC nozzles:

    Su-57 Stealth Fighter: News #8 - Page 38 Thrust-vectoring-735x413

    Su-57 Stealth Fighter: News #8 - Page 38 J200_t10

    Su-57 Stealth Fighter: News #8 - Page 38 Images?q=tbn:ANd9GcSFoFlbyg1_gvs7Krt_zo4bUZTjKi8tZyU1OmKJbXinMuT0pWyfE-jalBtxjHvjhjxkDUE&usqp=CAU

    We can see that the 3D nozzles have at least three or more actuators for the ring attachment, and multiple actuators in the supersonic region of the nozzle in the shape of the letter Y.
    This solution is much more complicated, but it provides full 3D thrust vectoring.
    Both solutions have advantages and drawbacks, and I have listed most of them in my previous post.

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    Post  Mir Sun Jan 14, 2024 1:51 pm

    @PeregrineFalcon

    I totally agree with your post but I believe there is not such thing as quasi 3D. It's either 2D or 3D.
    But it's fine with me if you believe differently  Smile

    Here is why:

    • Single-Axis TVNs: (also called 2-D or Pitch-only)
    The deflection of the gas flow is achieved in vertical direction only. They replace and/or complement horizontal control surfaces. This type is suitable for
    all types of variable geometry military aircraft nozzles, for applications without Post-Stall.

    • Multi-Axis TVNs: (also called 3-D or Pitch and Yaw)
    The deflection of the gas flow is achieved in any direction. They replace and/or complement horizontal and vertical control surfaces. This type is specially
    suitable for round nozzles, for applications with Post-Stall.

    The Sukhois canted TVC nozzles can achieve gas flow in any direction due to some clever, yet simple engineering.
    This is obviously only possible with two engines.

    The flat spin comparison confirms just what I said about the F-22. The center of gravity axis is clearly somewhere in front of the F-22. The cameraman has to go look for the F-22 - which is a clear indication for me.

    The camera has no problem following the Su-57 though as the rotation is around it's own center of gravity. But again that is just my opinion.
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    Post  Mir Sun Jan 14, 2024 4:38 pm

    Just noticed something very funny. Coincidence or what?!

    In my post 906 I posted a translated piece from Wikipedia.ru that reads as follows:

    List of aircraft fitted with a 3D axis-symetrical vectoring nozzle;

    Rockwell-MBB X-31 (Experimental aircraft of the X-planes series)
    MiG-29OVT
    MiG-35 (optional)
    Su-27SM2 (AL-31F-M1 engine, Product 117S)
    Su-30 (AL-31FP engine)
    Su-35S
    Su-37
    Su-57
    F-15S (experimental)

    The page has now been edited extensively to the following:

    Vectoring in two dimensions

    McDonnell Douglas F-15 STOL / MTD (Experimental)
    Lockheed Martin F-22 Raptor (pitch only)[28]
    Chengdu J-20 (earlier versions with WS-10C,[29] pitch and roll)
    McDonnell Douglas X-36 (yaw only)[27]
    The Me 163 B experimentally used a rocket steering blade for the yaw axis
    Su-30MKI /MKM / MKA / SM (pitch and roll)
    Sukhoi Su-35S
    Sukhoi Su-57

    Vectoring in three dimensions

    McDonnell Douglas F-15 ACTIVE (experimental)
    Mitsubishi X-2 (Experimental)
    McDonnell Douglas F-18 HARV (experimental)
    General Dynamics F-16 VISTA (experimental)
    Rockwell-MBB X-31 (experimental)
    Chengdu J-10B TVC Testbed (experimental)
    Mikoyan MiG-35 (MiG-29OVT, non-production aircraft)
    Sukhoi Su-37
    Sukhoi Su-47

    The above is also verbatim on the English version Laughing

    The idiot who edited these pages made a huge mistake however - both the Su-37 and Su-47 (S-37) only had 2D TVC's.  What a Face

    As for the all moving nozzles presented on Combat Approved - I'll leave it at that.

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    Post  PeregrineFalcon Sun Jan 14, 2024 11:04 pm

    Mir wrote:@PeregrineFalcon

    I totally agree with your post but I believe there is not such thing as quasi 3D. It's either 2D or 3D.
    But it's fine with me if you believe differently  Smile

    Here is why:

    • Single-Axis TVNs: (also called 2-D or Pitch-only)
    The deflection of the gas flow is achieved in vertical direction only. They replace and/or complement horizontal control surfaces. This type is suitable for
    all types of variable geometry military aircraft nozzles, for applications without Post-Stall.

    • Multi-Axis TVNs: (also called 3-D or Pitch and Yaw)
    The deflection of the gas flow is achieved in any direction. They replace and/or complement horizontal and vertical control surfaces. This type is specially
    suitable for round nozzles, for applications with Post-Stall.

    The Sukhois canted TVC nozzles can achieve gas flow in any direction due to some clever, yet simple engineering.
    This is obviously only possible with two engines.

    The flat spin comparison confirms just what I said about the F-22. The center of gravity axis is clearly somewhere in front of the F-22. The cameraman has to go look for the F-22 - which is a clear indication for me.

    The camera has no problem following the Su-57 though as the rotation is around it's own center of gravity. But again that is just my opinion.

    I have never said there is such a thing as quasi 3D TVC nozzle, I have stated that by using two widely spaced canted 2D TVC nozzles you can create quasi 3D TVC effect.

    Here is the 360 deg. view of the rear of the Su-35S:



    You can adjust the camera to watch only one engine and elevator, or both engines, and it is clear as day that the nozzles can only move up and down at an angle, but with differential/independent engine deflection, and with aerodynamic surface deflection you get control in pitch, yaw and roll.

    Mir wrote:

    As for the all moving nozzles presented on Combat Approved - I'll leave it at that.

    Su-57 Stealth Fighter: News #8 - Page 38 Ca-scr14

    Like I have previously stated, there are also AL-31F engine with KLIVT type 3D TVC nozzle:



    The reporter could be easily talking about/filming that type of nozzle, but that nozzle is not used by operational Sukhoi fighters.

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    Post  Mir Mon Jan 15, 2024 1:09 am

    @PeregrineFalcon

    I have never said there is such a thing as quasi 3D TVC nozzle, I have stated that by using two widely spaced canted 2D TVC nozzles you can create quasi 3D TVC effect.

    AND I have never mentioned "quasi 3D TVC nozzles" at all. I actually referred to the "quasi 3D TVC effect" you mentioned.

    "Quasi" means resembles or resembling something. In this instance you can not possibly "resemble" a 3D effect in flight. Flying an aircraft is 3D. You can't imitate or resemble 3D whilst you're flying in a real aircraft in a real 3D environment. You can only resemble or imitate it in virtual reality.

    A Su-57 using it's canted TVC engines cannot possibly make a "quasi J-turn" or a "quasi Cobra Turn" for instance. Even less so - a quasi controlled flat spin. Although that F-22 controlled spin looked kind of "quasi" to me   Wink Laughing

    You can adjust the camera to watch only one engine and elevator, or both engines, and it is clear as day that the nozzles can only move up and down at an angle, but with differential/independent engine deflection, and with aerodynamic surface deflection you get control in pitch, yaw and roll.

    I have absolutely no problem with that and what's more - "you get control in pitch, yaw and roll." which makes it 3D for real - not "quasi" Wink Laughing

    Btw do you have something concrete on the different nozzle options on the AL-51 engine?
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    Post  PeregrineFalcon Mon Jan 15, 2024 6:09 am

    Mir wrote:@PeregrineFalcon

    I have never said there is such a thing as quasi 3D TVC nozzle, I have stated that by using two widely spaced canted 2D TVC nozzles you can create quasi 3D TVC effect.

    AND I have never mentioned "quasi 3D TVC nozzles" at all. I actually referred to the "quasi 3D TVC effect" you mentioned.

    "Quasi" means resembles or resembling something. In this instance you can not possibly "resemble" a 3D effect in flight. Flying an aircraft is 3D. You can't imitate or resemble 3D whilst you're flying in a real aircraft in a real 3D environment. You can only resemble or imitate it in virtual reality.

    A Su-57 using it's canted TVC engines cannot possibly make a "quasi J-turn" or a "quasi Cobra Turn" for instance. Even less so - a quasi controlled flat spin. Although that F-22 controlled spin looked kind of "quasi" to me   Wink Laughing

    You can adjust the camera to watch only one engine and elevator, or both engines, and it is clear as day that the nozzles can only move up and down at an angle, but with differential/independent engine deflection, and with aerodynamic surface deflection you get control in pitch, yaw and roll.

    I have absolutely no problem with that and what's more - "you get control in pitch, yaw and roll." which makes it 3D for real - not "quasi" Wink Laughing

    I called it "quasi" 3D effect because even highly separated, canted 2D TVC nozzles can't make the same 3D effect real 3D TVC nozzles can.
    Only in conjunction with aerodynamic surfaces that are used to counteract unwanted motions made by canted 2D TVC nozzles, the pilot can point its nose in desired direction. Without that you can't make the same level of precision and control you get with true 3D TVC nozzles that is necessary for real combat application.

    Here is the screen shot of the Mig-29OVT during flat spin:

    Su-57 Stealth Fighter: News #8 - Page 38 Ovt10

    All aerodynamic surfaces are basically in neutral/most optimal position.

    Here is the screen shot of of the Su-57 during flat spin:

    Su-57 Stealth Fighter: News #8 - Page 38 Fs10

    All aerodynamic surfaces (LEVCON's, flaps, ailerons, horizontal tails) are differentially deflected to counteract the rolling motion, in order to isolate the yaw motion.
    Without that you wouldn't be able to have precise and controlled flat spin you get with pure 3D TVC.

    I hope you now understand why I have used word "quasi"?!



    From reliable sources we know that there is also possibility that there will be optional true 3D TVC nozzle available, and flat/low observable TVC nozzle. It all depends on costumer demand.

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    Mir
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    Post  Mir Mon Jan 15, 2024 3:28 pm

    @PeregrineFalcon

    OOPS!  Embarassed  Embarassed  Embarassed

    Can't wait for you to explain this one Laughing Laughing Laughing

    (about 6 minutes in from the video link GarryB kindly provided on the Mig-29OVT)

    Su-57 Stealth Fighter: News #8 - Page 38 Oops-s10

    The smoke is always a good indication of the aircraft's orientation in the air.

    So no your "quasi" theory doesn't fly well with me Laughing
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    Post  LMFS Mon Jan 15, 2024 5:10 pm

    If you don't understand that it is not the same 3D TVC than canted 2D + control surface deflection, which is affected by airspeed and AoA, then PeregrineFalcon cannot do anything more to help you. He has already explained the issue in full detail for anyone wanting to listen.
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    Post  Mir Mon Jan 15, 2024 5:31 pm

    Keep your panties on bro!

    But at the same time why is the 3D vectoring Mig-29OVT flapping like a birdie in a controlled spin then?

    Su-57 Stealth Fighter: News #8 - Page 38 Oops2-11

    PeregrineFalcon wrote:I called it "quasi" 3D effect because even highly separated, canted 2D TVC nozzles can't make the same 3D effect real 3D TVC nozzles can.

    This Su30SM seems to be doing just great with it's 2D canted engines - so I'm calling the "quasi 3D" theory BS. dunno



    Sorry if all this upsets you. Rolling Eyes
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    Post  PeregrineFalcon Tue Jan 16, 2024 12:07 am

    Mir wrote:@PeregrineFalcon

    OOPS!  Embarassed  Embarassed  Embarassed

    Can't wait for you to explain this one Laughing Laughing Laughing

    (about 6 minutes in from the video link GarryB kindly provided on the Mig-29OVT)

    Su-57 Stealth Fighter: News #8 - Page 38 Oops-s10

    The smoke is always a good indication of the aircraft's orientation in the air.

    So no your "quasi" theory doesn't fly well with me Laughing

    It is very simple explanation, but I doubt that you will grasp it since you had trouble following me thus far?!

    Here is the video with much better resolution from where I have took the screen shot:



    Maneuver starts at 3:50, and even before it finishes the loop, Mig-29OVT is entering flat spin very aggressively!
    In doing so it creates huge amounts of side slip, and aerodynamic controls/surfaces (predominantly the horizontal tails), are actually supplementing/supporting TVC since the plane is having intelligent FCS. If the tails can be used to control the pitch to some degree, there is more authority for the TVC to control the side slip and initiate/control yaw.
    As the plane becomes more stable during flat spin, aerodynamic surfaces need less input and are put in the most optimal position where they create less drag and provide more lift.

    Now, if we take the screen shot from the video of the Su-30MK you have provided, we can see differential deflection of all aerodynamic surfaces, where their main role is to counter the roll motion created by the differential deflection of the canted 2D TVC nozzles. Exactly the same as with the Su-57!

    Su-57 Stealth Fighter: News #8 - Page 38 Sm10

    Here is translated patent paper for the PAK FA:

    http://pro-samolet.ru/blog-pro-samolet/395-the-patent-for-the-fighter-t-50-pak-fa

    Su-57 Stealth Fighter: News #8 - Page 38 Patent-t50-pakfa-25big

    There they explain how TVC is working.
    On schematic diagram we can see that the number 16 is showing the canted angle of the nozzles, and number 17 is showing the plane of rotation, which is only up and down. They also say that the nozzles can be deflected uniformly, or differentially where they create roll and yaw motions.

    For the same reason, canted 2D TVC nozzles can never provide the same level of controlability true 3D TVC nozzles can, and that is the reason I have used word "quasi"!
    Only in conjunction with intelligent FCS and aerodynamic surfaces that can counter unwanted motions can this combo provide control in pitch yaw and roll.
    With 3D TVC there is absolutely no need for that since the nozzle can point in every direction independently, and aerodynamic surfaces are used to supplement and enhance the contractility of the plane.

    Here is an example:

    Su-57 Stealth Fighter: News #8 - Page 38 Main-q10

    When you have differential deflection of the canted 2D TVC, you create yaw and roll motion at the same time.
    We can see that the both nozzles are pointing to the left, and in doing so they push the nose to the left, but at the same time left nozzle is pushing the plane up, and the right nozzle is pushing the plane down creating the roll to the left.
    Now imagine if there were no countering of the rolling motion with aerodynamic surfaces during flat spin?!
    The plane would start to point its nose to the left, but at the same time it would start to roll to the left and would flip the plane on its back which would make the plane to enter uncontrolled spin. That is the reason FCS is countering rolling motion with the aerodynamic surfaces in order to isolate the yaw to the left. Of course, there are many variations in between, but I don't have time to explain it to you.

    If you are not able co understand that, I can't help you!
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    Post  Mir Tue Jan 16, 2024 2:01 am

    I'm going to be brief as I am no longer going to waist my time here, and you are also beginning to rely on snot nose mentality level insults now.

    Here is your first screenshot of the Mig-29OVT during flat spin:

    Su-57 Stealth Fighter: News #8 - Page 38 Mig29o10

    Even in this screenshot you posted you can clearly see the slats going down and the rudder on the vertical stabilizer moving to the outer position inducing yaw - despite having 3D nozzles. There is also some movement on the horizontal stabilizers and the flaps.

    Yet you boldly claimed:

    PeregrineFalcon wrote:All aerodynamic surfaces are basically in neutral/most optimal position.

    PeregrineFalcon wrote:All aerodynamic surfaces (LEVCON's, flaps, ailerons, horizontal tails) are differentially deflected to counteract the rolling motion, in order to isolate the yaw motion. Without that you wouldn't be able to have precise and controlled flat spin you get with pure 3D TVC.

    Then I showed you a flapping Mig-29OVT in a controlled spin rubbishing your initial claims but now you have a another interesting explanation as to why that would actually happen - despite what you claimed above.  Laughing

    Btw the Mig-29's "aggressive" flat spin is not nearly as aggressive as the Su30SM - so really nothing special that the Sukhoi with it's canted engines can not do.  dunno

    In an earlier post you also made this claim

    PeregrineFalcon wrote:Without that you can't make the same level of precision and control you get with true 3D TVC nozzles that is necessary for real combat application.

    Question1: If 3D TVC nozzles were so great as you claim then why aren't there a  single operational aircraft with a 3D nozzle in service?
    Question2: If 3D TVC nozzles were so great as you claim then why did Sukhoi opt for the canted engines as they have already fully developed a 3D capable AL-31 version?

    I think the Sukhois are doing pretty well in real world combat so far.

    PeregrineFalcon wrote:...They also say that the nozzles can be deflected uniformly, or differentially where they create roll and yaw motions...

    Sorry you had to waist so much time explaining something I already knew.  I have repeated this line so many times here but it seems that some people just can't get it!

    Here it is for the very last time.

    Mir wrote:The canting allows roll and yaw moments by vectoring each nozzle differentially, thus enabling the aircraft to produce thrust vectoring moments about all three aircraft axes, pitch, yaw and roll.

    PeregrineFalcon wrote:If you are not able co understand that, I can't help you!

    At least try and be more original when you try to insult me - but I guess the same quote above applies to you!
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    Post  PeregrineFalcon Tue Jan 16, 2024 8:01 am

    Mir wrote:I'm going to be brief as I am no longer going to waist my time here, and you are also beginning to rely on snot nose mentality level insults now.

    Here is your first screenshot of the Mig-29OVT during flat spin:

    Su-57 Stealth Fighter: News #8 - Page 38 Mig29o10

    Even in this screenshot you posted you can clearly see the slats going down and the rudder on the vertical stabilizer moving to the outer position inducing yaw - despite having 3D nozzles. There is also some movement on the horizontal stabilizers and the flaps.

    Yet you boldly claimed:

    PeregrineFalcon wrote:All aerodynamic surfaces are basically in neutral/most optimal position.

    PeregrineFalcon wrote:All aerodynamic surfaces (LEVCON's, flaps, ailerons, horizontal tails) are differentially deflected to counteract the rolling motion, in order to isolate the yaw motion. Without that you wouldn't be able to have precise and controlled flat spin you get with pure 3D TVC.

    Then I showed you a flapping Mig-29OVT in a controlled spin rubbishing your initial claims but now you have a another interesting explanation as to why that would actually happen - despite what you claimed above.  Laughing

    What insults are you talking about?!

    I was just predicting that you probably won't be able to understand what I'm talking about, and after reading your post I came to conclusion that I was 100% right! And not only that, you are constantly manipulating and nitpicking with your statements, and you are also using my quotes that are taken out of context to make a point, but I will address that latter.

    Regarding Mig-29OVT screen shot, it is absolutely normal for the slats to be extended at high AoA, why is that even an issue?
    It is just you trying to find something in attempt to discredit me, but that only tells me that you don't have a clue what are you talking about, because if you did, you would also know that at such high AoA, close to 90 deg. vertical stabilizer/rudder is practically useless because of the turbulent wake. Basically, entire airframe is blocking incoming airflow and the rudder doesn't have authority to induce yaw.
    That is just the function of the CLAW (control law) of the FCS that is blending rudder input with TVC input at high AoA. When pilot is pushing the pedal, both the rudder and TVC are deflected at critical AoA.

    I have used that particular screen shot of the Mig-29OVT as an clear example that the plane can rotate during flat spin just as easily with aerodynamic control surfaces more or less in neutral position, as an clear contrast to the Su-57 so that you could better understand the difference between true 3D TVC and canted 2D TVC and the way they operate.
    And that difference is highlighted by the fact that you will never see the Mig-29OVT with the same position of the aerodynamic control surfaces you can see in Su-57 or Su-30SM during flat spin.

    The fact that we can see MIG-29 OVT aerodynamic control surfaces deflecting more during initial stage of the flat spin is not in contradiction with what I have previously said, it is just supporting the fact that you will get even better results at critical stages of maneuver with aerodynamic control surfaces supplementing TVC.
    In the case of the Su-57, their primary role during flat spin is to counter unwanted motion made by differential thrust vectoring of the canted 2D nozzles, which in turn provides precise nose pointing capability.

    Is this bold enough for you, or you still don't get it?!

    Mir wrote:

    Btw the Mig-29's "aggressive" flat spin is not nearly as aggressive as the Su30SM - so really nothing special that the Sukhoi with it's canted engines can not do.  dunno

    In an earlier post you also made this claim

    PeregrineFalcon wrote:Without that you can't make the same level of precision and control you get with true 3D TVC nozzles that is necessary for real combat application.

    This is clear example of you trying to manipulate with what was said, and taking my statements out of the context! And that is the reason I will continue to intellectually rape you, even if this is just waste of my time!
    First, I have never said that the Mig-29OVT flat spin is more aggressive than Su-30SM flat spin, I have said "Maneuver starts at 3:50, and even before it finishes the loop, Mig-29OVT is entering flat spin very aggressively!"
    When you enter maneuver at higher speed and G load, you also have higher inertial forces that are acting on all axis that need to be restrained, and there we can see horizontal stabs deflecting uniformly to provide assistance in controlling the pitch axis, and at the same time providing TVC higher authority for controlling the yaw/rolling motion.

    You will never see that in the case of Su-57, Su-30SM etc.

    So, here is my full quote, "All aerodynamic surfaces (LEVCON's, flaps, ailerons, horizontal tails) are differentially deflected to counteract the rolling motion, in order to isolate the yaw motion.
    Without that you wouldn't be able to have precise and controlled flat spin you get with pure 3D TVC.
    "

    In essence, I was never arguing what plane has superior nose pointing capability, it's just you trying to deflect from original debate which was about type of thrust vectoring and the way they operate.
    What you don't understand is the fact that some planes are better suited for post stall maneuverability than others, and based on the stall point, position of the center of gravity, center of lift (weather the plane is more or less stable, or unstable) its behavior is going to be different at critical AoA. Some planes will need more balancing from the TVC, some will need less, some planes will naturally be inclined to move the nose faster, some will be slower etc.
    So, it is not all coming down to the type of TVC, because there are so many other factors that will influence controlability of the plane at post stall region.
    For example, Su-57 was designed from the ground up to be able to exploit post stall region better than any other plane before it, and its aerodynamic configuration/shape is made accordingly, while the Mig-29 was never designed to operate in that region.

    Mir wrote:

    In an earlier post you also made this claim

    PeregrineFalcon wrote:Without that you can't make the same level of precision and control you get with true 3D TVC nozzles that is necessary for real combat application.

    Question1: If 3D TVC nozzles were so great as you claim then why aren't there a  single operational aircraft with a 3D nozzle in service?
    Question2: If 3D TVC nozzles were so great as you claim then why did Sukhoi opt for the canted engines as they have already fully developed a 3D capable AL-31 version?

    I think the Sukhois are doing pretty well in real world combat so far.

    First, there is absolutely no doubt that 3D TVC alone can provide superior controlability compared to 2D TVC, period!

    Secondly, I have already given you answers for your questions, but you obviously have some problems with reading?!

    Here is the quote:

    "First, such solution is much more simpler with less moving parts, which is beneficial for the jet engine life cycle and ease of maintenance.
    From the RCS perspective, it is much more easier and efficient to have less moving parts and intersections.
    Also, the engine plume is uniformly putting the pressure on the nozzle walls which is not the case with the full 3D nozzle, and one of the main problems for the 3D nozzles in general was exhaust plume leakage.
    Also, as can be seen, 3D TVC is less efficient regarding metal angle and plume angle deflection. You can have for example 15 deg. of metal angle deflection (nozzle deflection), but the plume deflection is always less than metal deflection.  
    Next, we can see plume spikes with 3D TVC deflection, and that is additionally reducing plume/thrust efficiency.

    And since you have two widely spaced engines, you can create 3D TVC effect with canted differential nozzle deflection and clever FCS.
    As a matter of fact, if we compare the Su-57 to J-10B with full 3D TVC, we come to conclusion that not only that the J-10B is not superior, but inferior in high AoA controlability and in nose pointing capability/rate. Also, fighters with one TVC engine can not create rolling moments, you need two engines for that, and while the 3D TVC is beneficial for the one engined plane, there are not many advantages compared to the two engined fighter with widely spaced, canted 2D TVC nozzles."

    End of quote!

    So, your attempt to try to frame me the notion that I think that planes like Su-30SM/35S/57 are not capable in the real world scenario is just pathetic!

    But this canted 2D TVC arrangement will not work so well on other fighters. Try putting it on Mig-29, and you will definitely degrade its performance in comparison to OVT because its engines are not as widely spaced as with the Flanker family, so you get less moment arm and torque.
    F-22, F-15, EF2000, Rafale etc. would be even worse in this regard!

    Mir wrote:
    PeregrineFalcon wrote:...They also say that the nozzles can be deflected uniformly, or differentially where they create roll and yaw motions...

    Sorry you had to waist so much time explaining something I already knew.  I have repeated this line so many times here but it seems that some people just can't get it!

    Don't be sorry, if you actually knew how this system operate, we wouldn't have this kind of conversation!
    There are multiple occasions where you have claimed that the nozzles also have capability to move left and right which is pure nonsense!

    Mir wrote:

    PeregrineFalcon wrote:If you are not able co understand that, I can't help you!

    At least try and be more original when you try to insult me - but I guess the same quote above applies to you!

    Would you rather want me to call you a retard?
    Would that be more original because if you continue this path, that is going to be appropriate label for you?!
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    Post  GarryB Tue Jan 16, 2024 8:30 am

    Here is translated patent paper for the PAK FA:

    Interesting that the all moving vertical tail surfaces seem to be aligned to the angle of cant on the vectored thrust engines... I suspect this is not an accident and makes flight control surface deflection calculations easier or should I say simpler.

    The deflections of the physical control surfaces during a flat spin mean nothing because in a flat spin they wont be capable of providing a useful consistent force to get the aircraft out of the spin as those control surfaces require a smooth clean airflow over them for their deflection to create a force on the cg and axis of the aircraft.... all the control surfaces could be neutral or deployed to their limits, but in a flat spin they wont effect the aircrafts movement through the air because it is spinning and not "flying". It would be like pressing the brake pedal or applying the hand brake on a car in the middle of a jump into the air.

    The Russians have been very clever and have been able to use 2D TVC to get all the benefits of 3D TVC flight but with the weight and cost savings of 2D TVC engines.

    They are clever buggers and have once again managed to get superior flight performance at massively reduced costs and prices.

    Call it quasi 3D or 2.5D or just 3D.... who cares anymore.

    Actual 3D TVC are really only important in one area and that would be VSTOL fighters because without them you add enormous weight and complication to a VSTOL fighters design because at very low speeds like the hover after takeoff or just before landing a 2D control jet engine is not good enough so aircraft like the Harrier and the Yak-38 and the Yak-141 required high pressure piping and fans at the tail and the nose and the wing tips with puffer jets running from high pressure gas from the main engine to allow precise control in the hover where the controls surfaces were useless (like they are in a flat spin, where you normally exit through engine thrust differential and luck).

    With full 3D TVC engines for the main engines and the lift engines you could do away with the weight and complication of puffer jets for control at landing and takeoff or the hover.

    Imagine a design for a fighter with forward swept wings with engines mounted on the wingtips and at the tail of the aircraft... with 3D TVC engines that would be all you would need and in normal flight the wingtip engines could provide forward thrust... they could even be electric... or you could mount them either side of the cockpit... being electric they would essentially be a turbofan engine but without the hot core turbojet so the airflow would be dense cold air that could be directed over the wing aerofoil for extra lift... you could even direct the airflow from them into the main engines located at the tail to increase thrust at takeoff where the low forward speed limits the airflow through the engines.

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