Sorry but flat nozzle for Su-57 ??? May I ask for which engine as it is logical ? AL-51F which has nozzle with serated petals or for completely new one that is in fact 6 gen engine like many Russian sources wrote about .
OK but we already know that there is a new gen engine and many sources gave info about that couple a years ago. If we talk about the possibility that maybe Izd 30/AL-51F can get these new nozzle we must keep on mind that Izd 30 has some inovations like it has no classic AB chamber at all.
''В «Изделии 30» форсажной камеры как таковой не будет. Вместо неё появилась кольцевая система, которая будет создавать сгорание топлива без его дополнительной подачи по насосным системам, что будет экономичнее. ''
Transl
''In Product 30 there will be no afterburner chamber as such. Instead, a ring system has appeared that will create fuel combustion without additional supply through pumping systems, which will be more economical.''
Marchukov talked about flat nozzle for gen5 engine for Su-57.
I remember providing transcript from his speech. He directly said that Sukhoi DB, likely on behest of Russian MOD demanded flat nozzle for new engine. And as Sukhoi isn't willing to change plane much, they had to resort to a complex design with 4 independent moving parts.
''In Product 30 there will be no afterburner chamber as such. Instead, a ring system has appeared that will create fuel combustion without additional supply through pumping systems, which will be more economical.''
Marchukov talked about flat nozzle for gen5 engine for Su-57.
I remember providing transcript from his speech. He directly said that Sukhoi DB, likely on behest of Russian MOD demanded flat nozzle for new engine. And as Sukhoi isn't willing to change plane much, they had to resort to a complex design with 4 independent moving parts.
If "four independent moving parts" mean fully variable convergent and divergent areas (stations A8 and A9), then it's not a bad thing from a performance perspective as it enables you to ensure more ideal expansion across various parts of the envelope.
However, the overall RCS reduction of the aircraft from a rectangular nozzle wouldn't be fully realized if the nacelles still remain cylindrical, but that kind of redesign would require much more structural and flight re-testing, and Sukhoi evidently avoided that as they wanted minimal changes to the air vehicle.
''On May 18, 2021, AEX.RU - A. Lulka Design Bureau - a subsidiary of"ODK-UMPO"is working on the formation of a scientific and technical backbone to create a sixth-generation engine for combat aviation. "This is a three-contour scheme, which the whole world is doing," Evgeny Marchukov, general designer of the Design Bureau, said at the ICAM-2020 conference. This is reported by the press service of the MAKSAir Show.
According to him, two options for implementing this scheme are being developed. The first stand tests of the demonstrator are due to take place in 2021. Using a three-contour scheme will allow to modernize the al-41F-1engine, improving its characteristics while maintaining dimensions.
In addition, as part of the creation of the NTH OCB, I.A. Lulki is engaged in such areas as a combustion chamber with wave detonation, a pulsating resonative detonation engine with a two-stage burning of kerosene-air mixture.''
Now some details about that '1164' .It was written that AL-Li Alloy 1164 was used only for some structural parts/ panels from prototype T-50-6 etc,so for the second stage prototypes with goal to reduce the weight by 100-120kg.This was done in accordance with construction documentation for the second stage prototypes.
After a while as we can read the problems went bigger and bigger and finally they decided to throw out that Alloy.Now I have some questions to ask. If '1164' was used from T-50-6 which Al-Alloy was used earlier ? We know for the problems with that big composite skin panel on the upper side of the centroplane which appeared earlier. Solution was found with that big cross Al Alloy section but which Alloy exactly? One more thing ,in the first part of the reportage 'From T-50 to Su-57' ,author Aleksey Egorov saw some details of the static strength testing of the T-50-7( sequences from 29th min ).Test was successful. It happened maybe during 2018 when reportage was made or even earlier.
What is this "1164" Al-Li alloy?? The book only mentioned attempting to use 1461 Al-Li alloy for "2nd Stage" structural redesign of the Su-57. It then pointed to issues with impact resistance, plastic deformation properties, and VIAM allegedly cherrypicking samples. The book even said that during the first round of loads testing on T-50-7, the design with 1461 Al-Li alloy failed in an unacceptable manner, and it was thereafter rebuilt using more traditional aluminum alloys like B-95 duralumin when it then passed loads tests. And yes the centroplane reinforcement had to replace the composite panel with aluminum alloy, which is there even on serial production airframes.
Sukhoi then mentioned that 1461 Al-Li alloy was removed from the "2nd Stage" prototype in stages to not interfere with construction schedule, and by the time of serial production airframes, only non-load bearing parts of Su-57 have that alloy.
Решающим фактором в вопросе внедрения нового алюминиево-литиевого сплава 1461, стало испытание статического образца Т-50-7, во время которого произошло веерное разрушение силовых шпангоутов в средней части фюзеляжа, а также отдельных стенок и поясов при достижении половины от расчетного случая нагружения. Результаты статических испытаний были ошеломляющими: конструкция планера разрушилась не в одном месте или нескольких локальных зонах, как это часто происходит, а масштабно, и в первую очередь причиной такого разрушения стало отсутствие зоны пластических деформаций материала перед разрушением. «Конструкция планера повела себя как старый сухой пень», что окончательно убедило главного конструктора М.Ю. Стрельца (с 2013 года) отказаться от использования данного материала в серийных Т-50 и перейти на детали из «классических» сплавов. Отказ от сплава 1461 в конструкции опытных образцов происходил постепенно и пошагово, поскольку опытные образцы Т-50-8, -9, -10 к тому моменту уже были заложены на стапелях). С каждым последующим вы- пущенным опытным образцом Т-50 доля сплава 1461 неуклонно снижалась (в первую очередь в высоконагруженных деталях) и к моменту создания Т-50-11 материал был практически полностью заменен, за исключением нескольких локальных мест в ненагруженных частях каркаса.
Полученные результаты прочностных испытаний восстановленной и доработанной статической машины Т-50-7 (с исключением сплава 1461) оказались положительными: конструкция планера второго этапа стала вести себя иначе по сравнению с конструкцией первого этапа: за счет внедренных изменений распределение нагрузок по планеру стало более равномерным, что позволило получить на статических испытаниях полный зачет по прочности.
It states, “перегрузка” - load factor for the sustained turns at the weight of 20000 kg (missiles included, 50% of fuel from the normal fuel load etc.)
The full lines represent the G load for the 8G limit, and intersected lines represent the G load when the exploitation 8G limit is exceeded/overridden.
If there was serious danger of destroying the airframe under 9G sustained turn at 20000 kg, there wouldn’t be such option on the EM chart, and the plane would be hard limited to 8G.
Your own chart shows that those lines terminate with hashed symbols, and above that, those lines are dashed. This strongly indicate that they're structural placard limits. This is specifically stated on the chart, “перегрузки,превышающие ограничения” or overload exceeds limits. The reference for 9g in the Su-27SK manual is used in conjunction with the 171,000kg overload under Mach 0.85, this overload chart may indicate a peacetime limit of 8g at 20,000kg, and I’ve not seen statements to say that ~171,200kg overload can be exceeded. So, I see nothing on how those limits can be exceeded, or by how much, other than assumptions. Probably it can aerodynamically pull that many g and structurally within the safety margin that’s designed for, but is structurally is off limits in normal use and severely reduces service life. Similar to the “paddle switch” on the F/A-18E/F Super Hornet that lets you override the g-limit but the aircraft immediately needs to be inspected for damage, so not a structural load it can regularly handle. Same with Su-27, pulling beyond the limit absolutely risks damaging airframe and is not to be done regularly.
Note this isn’t the same as F-15C with OWS, that system does raise the overall limit to 9g at appropriate weights. Without OWS, 7.33g.
And when we talk about lift to drag ratio, I have almost no doubt that Su-57 is superior in this regard. F-22 according to measurements has worse L/D ratio than Su-27 (11,6 vs 10,1 if I remember correctly).
Taking into account the amount of fuel F-22 can carry, it has very poor range (not so efficient engines and not so stellar lift to drag ratio will do that).
Su-57 is highly unstable plane (both in pitch and lateral direction) which provides excellent L/D ratio in subsonic/supersonic area, and that was possible to do with the use of LEVCON’s which can actively control the center of lift.
There was a study where they were comparing standard model with fixed LERX, and the one that had movable frontal part (LEVCON).
For example, the data for the 25 deg. AoA, shows that the model without LEVCON deflection has Cl - 0,726 and Cd - 0,329.
For the same AoA, model with LEVCON deflection has Cl - 0,835 and Cd - 0,364.
We can see significant increase in Cl and just a slight increase in Cd which leads to better lift to drag ratio.
But in practical terms, LEVCON deflection also decreases drag for the similar lift that is generated.
In other words, model with the LEVCON deflection can generate Cl - 0,742 at 20 deg. AoA, which is even greater than what the model without LEVCON deflection can generate at 25 AoA, but at the same time model with LEVCON deflection will have Cd - 0,241, which is significantly lower than the Cd for the model with fixed LEVCON.
Oh? What measurements do you have about the F-22's L/D? At what airspeeds? Validated by flight testing? Because this is entering into the territory of speculations down to a level of precision that's meaningless. And you're basing all your derivations and conclusions based on that?
And you say the Su-57 being unstable in pitch, which isn't even a unique feature of the aircraft as ALL modern fighters are unstable in pitch, beginning with the F-16. And to my knowledge the static margin of these fighters are unknown, nor the MAC aft limit so I don't see how this is a way to draw conclusions of anything.
Can you link me to this study? I like to know the source of your modeling and Cl and Cd numbers. Sure, the LEVCONs have aerodynamic benefits for the Su-57 shape but should not be considered an isolated benefit that can be individually compared to other aircraft without it. The LEVCONs are a way to control the particularly large strakes that the Su-57 has, an aircraft without similarly large strakes may not need it. And large strakes also add to surface area to increase parasitic drag.
All this can be modeled to an extent but unless they're from actual manufacturer modeling and data taking into account various fluid mechanics effects, and verified by flight testing, they can't be used to draw definite conclusions of anything.
Su-57 is basically using cropped delta wing, and here are the basic structural benefits from using such wing:
“The long root chord of the delta wing and minimal area outboard make it structurally efficient. It can be built stronger, stiffer and at the same time lighter than a swept wing of equivalent aspect ratio and lifting capability.
Its long root chord also allows a deeper structure for a given airfoil section. This both enhances its weight-saving characteristic and provides greater internal volume for fuel and other items, without a significant increase in drag. However, on supersonic designs the opportunity is often taken to use a thinner aerofoil instead, in order to actually reduce drag.”
...
We can see that the Su-35S can hold 4 missiles in the tunnel between air intakes and engines. If you just close that tunnel with doors you are not going to compromise the structural integrity of the plane.
In a sense, that is exactly what the Russians did with the Su-57.
They have applied proven solutions with blended wing-body layout, and they have calculated the optimal structural depth for the fuselage between the engines/intakes for structural rigidity, and they have added weapons bay doors at the point where they find it the most optimal for the weapons needed to be carried inside, while also taking aerodynamic properties into consideration.
Weapons bay doors are also stressed during high G maneuvering, so additional strengthening of the side walls (where they are attached) is needed.
We can see that on the drawing from the T-50 patent:
[/URL]
For that reason Su-57 doesn’t need the full depth bulkheads in that region, and the bulkhead between the weapons bays is simply additional strengthening measure.
Yes this is know, this is why YF-23 and F-22 also have a long root chord both for structural strength and for aerodynamics. And it's for this reason that Su-57 being significantly lighter than the F-22 is implausible unless there are restrictions or compromises elsewhere.
Your own image shows just how thin structurally the Su-57 is between the engines. And compared to a Su-27, the Su-57 carries much more of payload between the engines too.
A blended wing body layout does not somehow negate the principle of structural depth to better carry loads, it's the simple principle of area moment of inertia. Sure, Sukhoi may decide that the Su-57 doesn't need full depth bulkheads, but that's a conscious decision balanced by their desire for large payload between the engines, and result is a high risk structural design, something Sukhoi highlighted in their patent and tried to mitigate it. Even then, it still needed some compromises. The product card of the Su-57E, which has same airframe design as Su-57 except for IFF, fire control modes, cockpit instrument readings, and maybe the engines, show an overload of 8g, which is indicative of the structural risk.
Now, in my opinion the main reason for structural cracks during testing faze is predominantly tied to the materials used (that are not used in Su-35S construction).
Russians wanted to make the Su-57 as light as possible, and the new materials used were simply not adequate. Using different materials, that have somewhat higher specific weight has solved the problem.
The “Sukhoi book” states that the rejected alloy saved 100-120 kg, which is not that significant on the grand scale, and we can’t make educated guess how heavier Su-57 became, but most of the time almost every plane is getting heavier going from the prototype to operational stage.
But all available data suggests that the Su-57 is lighter than F-22, while being bigger plane dimensionally.
Sukhoi identified problem of the Su-57 design not having enough structural strength even before trying to incorporate new materials in "2nd Stage" redesign. T-50-1 and T-50-2 suffered from severe cracking even during MAKS 2011 despite flying at 5g, and this along with a host of other issues like certain fuel tanks not draining properly is what prompted the "2nd Stage" redesign. And the use of new alloys like 1461 Al-Li alloy was meant as a weight to reduce weight growth from this needed strengthening but it didn't fully pan out.
Sorry but all this does not indicate that somehow, the Su-57 despite having lower structural depth, more weapons and internal fuel, and does not use substantially different materials (similar amount of composites, more aluminum and less titanium than F-22) is somehow lighter in empty weight than F-22 without any kind of tradeoffs.
Basically the whole area behind the cockpit is essentially empty space that is susceptible to bending under high load, and that needs strengthening. Flat belly of the F-22, while not generating lift in the way body of the Su-57 does, is generating lift, and weapons bay doors, and air ducts are also stressed.
This is the bulkhead of the F-22 in the region in front of the engines where weapons bay ends:
...
In essence Su-57 retains all the advantages of the Flanker layout (highly maneuverable, huge range, big weapons capacity etc.) with not so much downside effects.
F-22 layout with close coupled engines and huge curved air intakes is the main limiting factor for the better exploitation of the internal space, and overall performance.
These statements about loads doesn't make sense, the Su-57 also has empty space that needs strengthening, and the structural "holes" where you have great reduction in structural depth happen along the wing chord where the loads are the highest. The structural "holes" on the F-22 from the weapons bays are mostly in front of the wings, and the bulkheads where the structure experiences the highest loads are almost all full depth.
I don't see how the F-22 structure is somehow less stressed than the Su-57, considering the placement of bulkheads and their depth at the highest loaded area, and the fact that it carries much more payload between the engines than the Flanker. And as said the Su-35 despite being an updated version of Su-27 with more modern materials also grew in empty weight. And keep in mind F-22 can pull 9g at takeoff weight of 64,000lbs or 29,000kg.
All this to say, the Su-57 is a capable design that fulfills some demanding requirements and have unique advantages in its class, like the very large internal weapon bay. And that is combined with excellent maneuverability. But one can’t ignore that this will cause some structural tradeoffs compared to an aircraft of similar construction and materials like the F-22, and the reduction in bulkhead depth will increases stresses that need strengthening. Maybe those tradeoffs aren’t operationally important, for example the Su-57 doesn’t need to pull 9g at takeoff weight of over 29 metric tons like the F-22 can, since it’s rarely ever the case in combat, so that’s where it can save structural weight. But, its not somehow a perfect airframe that able to do everything better and yet makes no tradeoffs whatsoever, when these basic structural principles are in play.
While the air intakes are Mach 3 capable, canopy, composites, and RAM will not allow for that speed (2600 km/h is the usual cited top speed), but my guess is that the Russians are aiming at Mach 2 supercruise with AL-51F-1 engines, where this type of intake will come handy.
Source that combat range is 3,500km? Is this with or without the weapon bay fuel bladders? The cruise range given in Su-57E product card (differing from Su-57 in IFF, cockpit instrument readings, some fire control modes, same airframe and engines) indicates different range numbers, given as:
Max range flight at altitude of cruise flight without refueling / with one refueling / with two refueling - 2,800km / 5,200km / 7,800km
But regardless these single numbers mean nothing without context or additional details.
Airshow turn rate comparison means nothing without knowing the weight. An F-16C at 22,000 lbs turns at 21.7 degrees per second. Increase weight to 26,000 lbs at near full fuel and it decreases by 4.4 degrees per second to 17.3, and the F-16C and F-22 demos are done at full fuel, and the minimum radius turn happens at the beginning of the demo. Sukhoi demos are not done at full fuel.
As always, nice beat down Rad.
After all this time(i been away for years in here), and people, and i mean the SAME people are still hyperbole everything about everything.
If we look at how long the Flanker has been in service and improved upon.
Id say we are far from seeing the mid term edition of Su-57.
I am pretty sure it will be something sweet.
But we don't know if this nozzle is for this jet or that that was simply tested on a "flying lab" for something destined for another aircraft.
Perhaps a larger aircraft..
The LOAN nozzle was the original nozzle solution for izd.30 and is applied to the izd.177 since they’re similar dimensions and compatible with same aircraft. In 2023, UEC Saturn in presentation said that the flat nozzle is a belated addition, and Sukhoi didn’t want to change airframe much, so they designed around existing airframe. Also explains the nacelles still being round as members here have mentioned.
Arkhip Lyulka Design Bureau is also working on a three-stream sixth-generation fighter engine.
aviationweek.com
Marchukov complained in his June speech that when the engine program for the Su-57 was launched, Sukhoi expressed no interest in a flat nozzle and only ordered it much later, when both the aircraft and engine were already formed. While the flat nozzle should be firmly integrated into the aircraft, Sukhoi “resists changes to the airframe itself,” he added.
“That’s why we came up with a rather complex flat nozzle,” Marchukov said.
...
But we don't know if this nozzle is for this jet or that that was simply tested on a "flying lab" for something destined for another aircraft. Perhaps a larger aircraft..
But why does "the larger aircraft" need engines whose thrust nozzles can rotate around the longitudinal axis ? See at 0:32 in the video (please view at 0.25x speed).
Strange logic in regards to the case. Patents were filed by ODK, not Sukhoi, and they perfectly fit Su-57 'bionical design' model with 2D nozzles from 80th anniversary documentary, another official desktop model, later presentations from RAS and Saturn, and new footage.
Also, the rear of izd.30 or AL-51F1 seem to have radar blocker and flame holder/spray bar similar to EJ200 or YF119? Although not full coverage like serial production F119.
the most intriguing part IMO
does this mean the real thing can change the vector of thrust in a rudder axis in addition to the standard pitch control via petals deflection?
Is this an official animation? I was under the impression that they just went up and down and the canted angle was used for the z axis, like the su-30, su-35 and current su-57
The flattened exhaust nozzle installed at an angle is planned to reduce the signature of advanced versions of the Su-57. The novel flattened exhaust nozzle is planned to reduce the radar signature of advanced versions of the Su-57 Felon fighter.
The raptor has less swept going for it and the camber on the tips of the wings, so it is not so clear which one could turn faster. I do thin the su-57 has more innovative aerodynamics. Now if only we had the f-23
Also, the rear of izd.30 or AL-51F1 seem to have radar blocker and spray bar similar to EJ200 or YF119? Although not full coverage like serial production F119.
What we can see here? Red arrow shows us skin plate of the Izd.30 ,yellow arrow to end of the skin plate and the place where we can see LOAN movements,blue of course shows to us LOAN itself.
Now let us see how the new nozzle is look like. Red arrow shows to us completely new skin panel,yellow arrow shows to us the end of it and grey arrow to the section for nozzle rotating in longitudinal axis.Blue arrow shows to us moveable part of the nozzle.
My question is, if this is Izd. 30/AL-51F with the new nozzle, why is there completely new upper skin panel ? Other detail ,if we look better ,lower skin panel of the engine nacelle is also new.If there is really AL-51F ,inside left engine nacelle, why they changed skin panels on it ?
Blue lines shows to us nacelle panels that are the same ,yellow shows us the place where we can see new panels,
As wrote before ,we can clearly see that Su-57M emblem on the vertical stabilizer so it means that this new engine is for the Su-57M ,not for Su-57. As some official sources said ( personally it was Yuriy Slyusar), AL-51F will be integrated into serial Su-57's from 2025 and all serial Su-57's with AL-41F1 will not get Izdeliye 30. As we know ,static tests for Izd 30 started in 2016 ,flight tests began in 2017 and lasted 7 years ( 2017-2024). Static tests of this completely new ( yes, 6 gen) engine started in 2021 and as we can see ,flight tests started at the end of 2024 and will last for years to come.
First flying prototype of Su-57M had first test flight on Oct. 21 2022 .Pilot was of course Sergey Bogdan. Su-57M is prototype of the Russian 5+/6 gen fighter with many technical inovations.As Sergey said several times,he achieved several test flights so far in which he didn't do anything at all from the takeoff phase ,flight itself and landing phase.He only monitored work of all systems.
On June 2023 it was released info from ODC that new 6th gen engine is testing...
В ОДК показали кадры испытаний двигателя шестого поколения для Су-57
''В Объединенной двигателестроительной корпорации (ОДК) проинформировали об успешном испытании двигателя шестого поколения для многоцелевого истребителя Су-57.Немалую роль в высоких эксплуатационных характеристиках нового двигателя будет играть плоское сопло.''
In the article we can see all those illustrations but also pic where we can see ''Su-57'' with new 6th gen engine.Pic was in fact photoshop from paralay. Many sources wrongly wrote that it was the start of the flight tests of that new engine.
Russian source where we can see that it is in fact AL-51F-1 with flat nozzle.There are pics where we can see nozzle with and w/o rotation section.
Первый канал российского телевидения представил трейлер фильма «Властелины неба», посвящённого 85-летию Опытно-конструкторского бюро им. Павла Сухого. Сам
aviation21.ru
P.S. If I am wrong about this ,I will apologize to all members.
New engines are not made so quickly, this is work for another 15 years. The letter that you read as the letter M is not it, it is 2 letters L in Russian transcription Л. That stands for Flying Lab (летающая лаборатория). English is not my native language, sorry for the mistakes.
Second part of the analysis after the first one .Here is some pics of Izd. 30
Now the illustration shown before. Nozzle itself is one rotatable block with all of that hydraulic and pneumatic cylinders that
would require significant changes on Izd 30.
Also as one member noticed where is the sense, the logic to spent so much time testing Izd 30 with LOAN and after so many years to start test it with the new nozzle???
I will repeat what Е. Marchukov said about 6 gen. engine in 2019.
''In parallel with the development of the second stage engine for the Su-57, designers are already creating the scientific and technical basis for the sixth generation engines. First of all, research is aimed at improving the specific characteristics of the power plant compared to fifth-generation engines.According to Marchukov, such a project involves adding a third external air stream to the power plant design. Thanks to this, it is possible to achieve low specific fuel consumption at supersonic cruising mode. When flying at subsonic speeds, the third air stream will be open. Thanks to this, the air flow from the fan will pass through the second and third stream and the engine will operate almost like a turbofan power plant with a high bypass ratio. In this mode, the power plant will have slightly greater thrust and significantly lower fuel consumption.During supersonic flight, the third stream will be completely closed, and the second partially, due to which the engine will operate as a power plant with a low bypass ratio.''
New helmet for the Su-57 pilots was also shown ... The helmet with NSTsI /HMD. It is obvious that pilot will see all parameters that will be presented on the wide-angle HUD ShKAI-5M.
Шлем дополненной реальности для лётчиков истребителей Су-57 (с) Кадр из видео «Первого канала»
This is not Izd.30. Your analysis with constant 'now we can be sure', 'we clearly see', 'apparently' often based on poor knowledge of things that long known or wrong assumptions. You remind me a guy from KPF who thought that every Russian patent filed in certain IPC class was directly related to PAK FA, presenting his wishful thinking as real things.
This is not Izd.30. Your analysis with constant 'now we can be sure', 'we clearly see', 'apparently' often based on poor knowledge of things that long known or wrong assumptions. You remind me a guy from KPF who thought that every Russian patent filed in certain IPC class was directly related to PAK FA.
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