Sukhoi Su-57 / T-50 / PAK FA first flight - pictures, videos and analysis [2010]

[Austin]

Well what does that link say ? Its all Russian

 

[overscan (PaulMM)]

Looks like AL-31F compressor blades, not a radar blocker. Certainly interesting.

 

[SOC]

Looks like its been fitted with an anti-spin parachute assembly between the tail fins.

 

[Sundog]

The simple facts are, this is an aerodynamic test bed, not the plane that will be tested for LO. As such, it doesn't have any need for a fan blocker to be installed at this time. I think people keep forgetting that this is a prototype, although probably much more production "representative" than the YF-22 was to the F-22, it's still just a prototype, and not a production aircraft.

Hell, maybe they are going to use plasma shielding for the fan face. There's a U.S. patent online for just such a feature from 1974. Who knows? All I can say is, they'll have something obscuring the engine face from EM sources when it goes into production.

Having said that, thanks for the great pics!

 

[Sundog]

Looks like its been fitted with an anti-spin parachute assembly between the tail fins.

a) Where do you see that? Are you talking about what looks like a cover to keep internal equipment warm or to keep the elements out of some test equipment before the first flight?

b) It already has drag chutes, which, to the best of my knowledge, most aircraft equipped with drag chutes have always used those chutes as anti-spin chutes if so required. Of course, the tails between the two flying prototypes are different, IIRC. Is that what you're talking about?

 

[SOC]

Look at the big image. There's a red something or other back between the tailfins, with what looks like a metal brace coming out of it. Could be a cover or something, but the way it's positioned made me think of the same type of assembly seen on the test Raptors. I think the J-10 used one of these things, and it has a drag chute as well.

 

[overscan (PaulMM)]

The simple facts are, this is an aerodynamic test bed, not the plane that will be tested for LO. As such, it doesn't have any need for a fan blocker to be installed at this time. I think people keep forgetting that this is a prototype, although probably much more production "representative" than the YF-22 was to the F-22, it's still just a prototype, and not a production aircraft.

Hell, maybe they are going to use plasma shielding for the fan face. There's a U.S. patent online for just such a feature from 1974. Who knows? All I can say is, they'll have something obscuring the engine face from EM sources when it goes into production.

Having said that, thanks for the great pics!

I agree totally, I'm just surprised they didn't use more curvature rather than relying on gizmos.

 

[Sundog]

I agree totally, I'm just surprised they didn't use more curvature rather than relying on gizmos.

Yeah, I know what you're saying, but adding curvature would be difficult with separated engine nacelles in the same plane, as opposed to the YF-23 which had the engines on top and inlets on the bottom. You would need a much wider nacelle to make them serpentine, or deeper. My guess is they figured they're going to pay some sort of penalty to protect the fans and the lowest cost/simplest solution, in terms of manufacturing and cost is just to throw an inlet blocker in it.

Of course, my thoughts on it are if Boeing didn't have any doubt they weren't going to have a problem, in that regard, with the X-32's inlet, then it should work equally well with the T-50. Of course, don't forget the T-50 has that inlet ramp door that drops almost halfway down the inlet from the top. In fact, I was trying to see if there was a ramp further up the inlet on the bottom to create a vertical serpentine, but it would have been difficult to slow the inlet flow down at supersonic speeds if they had done that. In fact, I had almost wondered if they had gone the B-1B route with vanes down the inlet. But those pics put the end to that idea.

I'm really looking forward to seeing some more high res pics of the T-50, only this time of it in it's camo, instead of those vid clips.

BTW, does anyone know if the second prototype has started flying? I remember they used it in the taxi tests, I just haven't heard more about it.

 

[lancer21]

Well from what i've read around lately at the moment the T-50-1( bort 51 black) here is the only flying article so far and is suposed to restart flying at Zhukovsky in April .

The T-50KNS is the full size engineering mockup ( non-flyable) that was used for ground tests since December 2009 including high speed trials ( this one has a slighly different model of boom between the engines).

Then theres the static airframe T-50-0 in Moscow recently shown during Putin's visit .

Aparently T-50-2 , the second flying prototype , is suposed to fly before the end of this year ...but maby our russian friends have more precise data.

 

[Abraham Gubler]

The simple facts are, this is an aerodynamic test bed, not the plane that will be tested for LO. As such, it doesn't have any need for a fan blocker to be installed at this time.

What and air flow to the engine is not something that's an important part of an aircraft's flight performance! However in defence of the T-50's frontal RCS - which has been clear from the get go was much lower (2-3 orders of magnitude at least) than a F-35 or F-22's - the aircraft has a very nose down attitude on its wheels (thanks to reusing design from the Su-27) which is the opposite of a typical nose up cruise atitude. What this means is the lower part of the engine face (which you can see in the pictures) is likely to be blocked from forward level view by the bottom part of the duct. Tactically significant stealth against 4th generation fighters; yes - LO; no.

 

[Sundog]

The simple facts are, this is an aerodynamic test bed, not the plane that will be tested for LO. As such, it doesn't have any need for a fan blocker to be installed at this time.

What and air flow to the engine is not something that's an important part of an aircraft's flight performance! However in defence of the T-50's frontal RCS - which has been clear from the get go was much lower (2-3 orders of magnitude at least) than a F-35 or F-22's - the aircraft has a very nose down attitude on its wheels (thanks to reusing design from the Su-27) which is the opposite of a typical nose up cruise atitude. What this means is the lower part of the engine face (which you can see in the pictures) is likely to be blocked from forward level view by the bottom part of the duct. Tactically significant stealth against 4th generation fighters; yes - LO; no.

My point about the aerodynamics is that they have to prove it flies correctly, before they begin to worry about the LO features. You aren't go to put a fan blocker in the inlet, that will effect the inlet aerodynamics, until you have the baseline aerodynamics covered. The inlet blocker just isn't that relevant at this point, in much the same manner that the first F-35s didn't have the finished system software or the lower weight production airframes. Not that that has helped the F-35 complete it's testing.

 

[saintkatanalegacy]

Ah well, good point. It's too early to be disappointed ;D

 

[Abraham Gubler]

Using inlet blockers will mean the T-50 will have no where near the same kind of low observable reduction in RCS as the F-22 (~5.5 orders of magnitude) and F-35 (~4 orders of magnitude). It is an example of the many compromises built into this design because Sukhoi could not afford to develop an all new vehicle system and had to work with the Su-27 structure and tooling. All of this is to be expected however based on the simple parametric of return on investment. You can’t expect a company that thinks building 25 airframes per annum is a great result to build a world standard, competitive air combat system.

 

[Avimimus]

I think that is probably premature.

The aircraft is clearly in an under-developed state and it is hard to know what will change. Furthermore, very few of us stand a chance at judging what choices are true design compromises and what choices represent adequate or optimum technological solutions.

We also don't really know how much engineering commonality there is with earlier Sukhois. Furthermore, many similarities may be the result of technological improvements that will become commonplace in future aircraft. We don't say that the B-52 used B-47's structure just because it inherited the swept wing and a number of other design features.

I personally can't see why people try to fit this airframe into "F-22 copy" or "warmed over Su-27" schemas. The fact that we are so intent on fitting it into categories means that it is probably something truly new. I think we should accept it for being a potters first draft and avoid generalisations until it has been export in 2020 or so.

 

[sferrin]

I think that is probably premature.

The aircraft is clearly in an under-developed state and it is hard to know what will change. Furthermore, very few of us stand a chance at judging what choices are true design compromises and what choices represent adequate or optimum technological solutions.

We also don't really know how much engineering commonality there is with earlier Sukhois. Furthermore, many similarities may be the result of technological improvements that will become commonplace in future aircraft. We don't say that the B-52 used B-47's structure just because it inherited the swept wing and a number of other design features.

I personally can't see why people try to fit this airframe into "F-22 copy" or "warmed over Su-27" schemas. The fact that we are so intent on fitting it into categories means that it is probably something truly new. I think we should accept it for being a potters first draft and avoid generalisations until it has been export in 2020 or so.

Er, "everybody thinks it looks like an existing aircraft therefor it must be truly new"? That's an "interesting" line of reasoning.

 

[Abraham Gubler]

I think that is probably premature.

very few of us stand a chance at judging what choices are true design compromises and what choices represent adequate or optimum technological solutions.

We also don't really know how much engineering commonality there is with earlier Sukhois

Speak for yourself…

Trying to reject an evidence based process of assessment because you don’t like the conclusions or don’t understand them or whatever does not make it go away.

The T-50 is heavily reliant on the Su-27. This is not a case of saying something to sound good or swept wing for swept wing or cosmetics. But rather based on the many key physical dimensions of the fuselage structure that align perfectly between the two aircraft produced by the same people one after the other in a very parsimonious financial environment. If it looks like a duck and quacks like one then it is most likely a duck.


This is not an attempt to categorise but to understand. Since we are talking about significant structural issues as opposed to what colour the paint is they are pretty much set in concrete. All Sukhoi have done to build the T-50 is widen the structure between the engine bays, add new intakes to the bays and leading edges to the fuselage and change the shape of the nose structure. To this fuselage they’ve added new wings and tails. A far more substantial change than the Hornet to Super Hornet but clearly not a clean sheet of paper design.


Of course everything I’ve said in this post I’ve also said earlier in this thread and an explanation as to why it would be so and what the Russians probably want to achieve with this aircraft. That this doesn’t align with various fanboy and partisan perspectives about the T-50 does not make it any less so.

 

[Austin]

Why should any one get dissapointed with Sukhoi uses a combination of Radar Blockers , RAM on engine blade and other means to get the same result for LO which say F-22,F-35 or YF-23 got it through other means ?

Is there just one single way to achieve the same result ?

The Russians according to their own literature managed to substantially reduce RCS from directly exposed engine blade when they applied RAM to it ( if memory serves me right it was 10- 15 times less than those without RAM )

If I am not wrong the designer of PAK-FA mentioned that the RCS of PAK-FA was not any better than F-22 , if comparison is what pleases every one.

Its possible that one has more than one way to achieve the same result , as long as they obtain it thats what matters.

 

[Abraham Gubler]

Is there just one single way to achieve the same result ?

It depends on what you are trying to achieve.

If you are trying to cut something from 100% to 10% or even 1% then there are probably many ways to do it. But if you are trying to cut something from 100% to 0.0001% or 0.00001% then your options narrow immensely because what you are trying to do is so significant.

Radar blockers for engine faces do not perform anywhere near the kind of RCS reduction of a stealthy inlet and fan blade RAM isn’t in the radar blocker league. When it comes to LO 10-15 times is small fry and won’t provide a significant reduction in radar detection range.

If you don’t understand the basic principles of LO (relationship between RCS reduction and radar detection range) then you really shouldn’t be injecting your opinion into a discussion about it.

 

[Austin]

We do not know what engineering solution was opted for to reduce PAK-FA RCS not just frontal but over all RCS , its just not possible to look at the pictures and say oh this is -20db or 30 or 40.

Its certainly not possible to have just one look at the first prototype to come to a general conclusion on its overall LO or the engineering solution adopted to reduce its RCS

There can be many ways or a combination of many things working together that can reduce the over all RCS .

But since you claim to be a Be All , Know All on LO and Patron on Stealth , I would not inject my opinion any more on this topic.

 

[Abraham Gubler]

But since you claim to be a Be All , Know All on LO and Patron on Stealth , I would not inject my opinion any more on this topic.

And where did I claim that? I simply pointed out that you appear not to understand R2/R1 = (sigma2/sigma1)1/4 in which case you don't know what you're talking about (R: maximum radar range, Sigma: RCS).

As to not "knowing" what method of RCS reduction is used in the T-50 its pretty straight forward. I don't "know" how the aircraft generates lift but I'm pretty sure its via a wing shape rather than pockets of lighter than air gas within the fuselage. Since the Russians have to follow the same physics as everyone else its pretty straight forward to make engineering conclusions based on what you can see of the aircraft. Which is why a lot of people far more informed than myself are talking down the claimed LO capability of the T-50.

 

[Austin]

^^^ What I am saying is simple , unless you are aware of the total engineering solution and integrated approach adopted ( and not by parts or pics ) to reduce PAK-FA RCS , its just open to speculation and mathematical equations.

It simply not possible to look at the picture or parts of radar blocker or shape of the first prototype and claim eureka its -20 - 30 db or its not LO or worst than F-18.

Some one has to be God to just know if that bird is a VLO or trash just by looking at the picture of first prototype and come to definitive conclusion.

By far its good to assume that RCS reduction measure have been adopted in the design but if that translates to -20db or worst or better is not possible to figure out looking at the picture.

If any one wants to believe the word of General Designer of PAK-FA the RCS of PAK-FA is no worse than F-22 , but then what does he know .... I guess we have experts out here who can figure out the RCS by looking at the pictures and radar blockers.

 

[Kovalchuk]

because Sukhoi could not afford to develop an all new vehicle system and had to work with the Su-27 structure and tooling.

That was probably the reason why Suhoi build Su-47 that had all pretty things like S-duct intakes, flat bottom. Then why to work with a "Su-27 structure and tooling" (what does that even mean? I guess SuperJet is a derivative of Su-27 since all Suhoi has is Su-27 tooling) when you could simply tweak Su-47?

I guess YF-23 was also a victim of "parsimonious financial environment" of Northrop/McDonnell Douglas:

or X-32

All Sukhoi have done to build the T-50 is widen the structure between the engine bays, add new intakes to the bays and leading edges to the fuselage and change the shape of the nose structure. To this fuselage they’ve added new wings and tails. A far more substantial change than the Hornet to Super Hornet but clearly not a clean sheet of paper design.

Hey look F-22 is just smoother version of F-15:

 

[lantinian]

Тhe aircraft has a very nose down attitude on its wheels (thanks to reusing design from the Su-27) which is the opposite of a typical nose up cruise atitude. What this means is the lower part of the engine face (which you can see in the pictures) is likely to be blocked from forward level view by the bottom part of the duct. Tactically significant stealth against 4th generation fighters; yes - LO; no.

I think you need to check your observations again. The exact opposite is true. The engine face is hidden during taxing because of the very low nose down design, not during cruise when the inlets and the engines re perfectly leveled.

I think, significant inlet duck curvatures, engine face blockers and other fancy engineering tricks to hide the blades are counterproductive to the most critical part of the whole program: the engine performance. I just read the flight International article, and it is clear that continued support of the program will hinge on the engines meeting their specifications.

Anything other than a strait cylindrical inlet duck affect the airflow negatively and hence engine performance. The current flight engines when compared to the F-22 ones from 10 years ago, produce trust less while they being bigger and heavier at the same time

 

[Trident]

Er, "everybody thinks it looks like an existing aircraft therefor it must be truly new"? That's an "interesting" line of reasoning.

Everybody? To paraphrase, speak for yourself.

I'm surprised Sukhoi decided to plan for a blocker (because that's what we'll see in the finished article, even if there is none at the moment, or they would not have put as much effort into shaping) rather than curved ducts. After all, the latter were already demonstrated on the Su-47. Then again, the F-32 design (aimed at meeting the same LO criteria as the F-35!) seemed to get away with a blocker, so I think Abraham Gubler's assessment is not a foregone conclusion. Performance could be a concern, however I read workshare distribution list for the new engine which suggests RCS reduction is being tackled as part of engine development - so the blocker could be matched well to the powerplant.

 

[saintkatanalegacy]

hmmm...

the engines re perfectly leveled.

halfway level tbh

 

[Trident]

It is an example of the many compromises built into this design because Sukhoi could not afford to develop an all new vehicle system and had to work with the Su-27 structure and tooling. All of this is to be expected however based on the simple parametric of return on investment.

Oh for crying out loud!

It's externally smaller than a Flanker, made from wholly different materials and Sukhoi was able to demonstrate and test an alternative fuselage design in the Su-47. Can we give that old chestnut a rest?

 

[Thorvic]

Quote from: Abraham Gubler on Today at 04:11:18
All Sukhoi have done to build the T-50 is widen the structure between the engine bays, add new intakes to the bays and leading edges to the fuselage and change the shape of the nose structure. To this fuselage they’ve added new wings and tails. A far more substantial change than the Hornet to Super Hornet but clearly not a clean sheet of paper design.

And thats a bad thing ?

The clean sheet approach doesn't appear to be that viable a concept these days, decades to evolve, billions over budget and orders butchered as a result. Yes you get a Rolls Royce of an Aircraft, but you were really looking for a more practical and affordable aircraft. ??? - Then again were talking about a country that spent thoundands developing a pen to work in space and russians used a pencil !!!

 

[AeroFranz]

I'm surprised Sukhoi decided to plan for a blocker (because that's what we'll see in the finished article, even if there is none at the moment, or they would not have put as much effort into shaping) rather than curved ducts. After all, the latter were already demonstrated on the Su-47. Then again, the F-32 design (aimed at meeting the same LO criteria as the F-35!) seemed to get away with a blocker, so I think Abraham Gubler's assessment is not a foregone conclusion. Performance could be a concern, however I read workshare distribution list for the new engine which suggests RCS reduction is being tackled as part of engine development - so the blocker could be matched well to the powerplant.

F-32 had no other option, as the engine was ahead of the cg, with very short inlet duct. Rule of thumb for S-duct is length = 3-5 times engine face diameter, depending on how aggressive you are with turning of the flow. I don't know how good blockers are these days, but I doubt their pressure recovery penalty is lower than a nice curved duct. The aforementioned constraints dictated by legacy structural design is the likely justification for their use.

 

[Avimimus]

Er, "everybody thinks it looks like an existing aircraft therefor it must be truly new"? That's an "interesting" line of reasoning.

Yes it is, isn't it? It has "some" validity though: http://en.wikipedia.org/wiki/Schema_%28psychology%29 B)

I think that is probably premature.

very few of us stand a chance at judging what choices are true design compromises and what choices represent adequate or optimum technological solutions.

We also don't really know how much engineering commonality there is with earlier Sukhois

Speak for yourself…

Trying to reject an evidence based process of assessment because you don’t like the conclusions or don’t understand them or whatever does not make it go away.

The T-50 is heavily reliant on the Su-27. This is not a case of saying something to sound good or swept wing for swept wing or cosmetics. But rather based on the many key physical dimensions of the fuselage structure that align perfectly between the two aircraft produced by the same people one after the other in a very parsimonious financial environment. If it looks like a duck and quacks like one then it is most likely a duck.

This is not an attempt to categorise but to understand. Since we are talking about significant structural issues as opposed to what colour the paint is they are pretty much set in concrete. All Sukhoi have done to build the T-50 is widen the structure between the engine bays, add new intakes to the bays and leading edges to the fuselage and change the shape of the nose structure. To this fuselage they’ve added new wings and tails. A far more substantial change than the Hornet to Super Hornet but clearly not a clean sheet of paper design.

Of course everything I’ve said in this post I’ve also said earlier in this thread and an explanation as to why it would be so and what the Russians probably want to achieve with this aircraft. That this doesn’t align with various fanboy and partisan perspectives about the T-50 does not make it any less so.

Well, let's see: If it is to be offered as a carrier variant it shouldn't have larger dimensions than an Su-33. If it is to keep with Russian survivability doctrines the engines will be far apart (a legitimate design choice with a >thirty year history). A wide space between the engines is also necessary to have the largest (and most flexible) internal bays. I don't really see how there are significant similarities which do not result from policy decisions (with the obvious suggestion of the borrowed engines and lack of radar on the aerodynamics test-bed).

If you can find any, I'd certainly be interested in hearing about it.

P.S. As someone with plenty of experience in biology I can say with confidence that it isn't always a duck. I can find some amazing examples of almost unrelated by nearly identical species.
Convergent evolution applies to aircraft as much as it does to organisms.

If you are trying to cut something from 100% to 10% or even 1% then there are probably many ways to do it. But if you are trying to cut something from 100% to 0.0001% or 0.00001% then your options narrow immensely because what you are trying to do is so significant.

An extremely good argument.

 

[sferrin]

Er, "everybody thinks it looks like an existing aircraft therefor it must be truly new"? That's an "interesting" line of reasoning.

Everybody? To paraphrase, speak for yourself.

Talk to Avimimus not me.

"The fact that we are so intent on fitting it into categories means that it is probably something truly new."

 

[saintkatanalegacy]

hmmm... so a bit of updating from the old one. . .

 

[SOC]

I guess YF-23 was also a victim of "parsimonious financial environment" of Northrop/McDonnell Douglas:

Bad example, given that this was not the production intake design.

 

[paralay]

B)

 

[Sundog]

F-32 had no other option, as the engine was ahead of the cg, with very short inlet duct. Rule of thumb for S-duct is length = 3-5 times engine face diameter, depending on how aggressive you are with turning of the flow. I don't know how good blockers are these days, but I doubt their pressure recovery penalty is lower than a nice curved duct. The aforementioned constraints dictated by legacy structural design is the likely justification for their use.

IIRC, the F-32 was to have a variable geometry fan blocker. But, I suspect pressure recovery won't be a problem if the inlet was designed to have it in place from the start. I could see if it was added as an after thought where that would be a problem. BTW, I don't know if the SH's fan blockers are fixed or VG. I assume fixed, but I don't know.

 

[Sundog]

Hey look F-22 is just smoother version of F-15:

I've said for years that the F-22 aesthetic is just "melted F-15." ;D

As for the YF-23 pic, you aren't looking at it from a direct forward view and you aren't behaving like a RADAR wave.

 

[joncarrfarrelly]

Then again were talking about a country that spent thoundands developing a pen to work in space and russians used a pencil !!!

That is a tiresome old BS myth:
http://www.snopes.com/business/genius/spacepen.asp

BTW a retracting-cord mechanical pencil attached to the control panel was developed for Gemini, and those cost $128 a piece.

 

[Matej]

How many of the last 20 posts were related to the PAK FA? Gents, please return to the topic or I will do. And you wont like it!

 

[Wil]

Hello

The "PAK FA in the night" is a great image!, Thanks friends.

Nice and simple solution for radar blocking. I think that there are two blockers:



And this other picture about the wingspan of PAK FA (image taken from Sukhoi video):



Hasta la vista!

 

[Abraham Gubler]

For the record and one last time I’ll restate that the similarity between the T-50 and the Su-27 is not based on ‘aesthetics’ or looking at the two of them side by side but by overlay of plan, side and forward views in which a wide number of key structural lines are identical. This is not a case of “convergent evolution” but actual “intelligent design”. To assume the former in this case is as ridiculous as assuming the later in biology with millions of years of evolution.

It doesn’t matter what Sukhoi did with the S-47 funded with Soviet money or the SuperJet funded with Italian money. In this case it is abundantly clear to anyone wanting to make an evidence based conclusion that the T-50 is not a clean sheet design but an evolution of the Su-27.

Now as to whether this is good or bad it depends on which metrics. It is clear that this is a bad thing in contributing to the RCS of the T-50. The Su-27 design inheritance compared to an F-22 type clean sheet design means a lot more complex shape with a range of radar reflecting hotspots and extremely difficult surfaces in which to build in radar absorption. On the other hand it is notably a lot cheaper and quicker and enables an aircraft with high agility to be built. But I know which one I’d bet on to win in a fight and it ain’t the T-50 “FLYHALF”.

 

[Sundog]

The T-50 has as much to do with the Su-27 as the F-22 does the F-15. They are both evolutionary designs of successful configurations. Sure, the designers study many other kinds of configurations, but it isn't surprising that given similar requirements to previous generations of fighters and the data base they're each working from they end up with designs with layouts similar to worked previously.

Besides, Sukhoi already made a fighter that was radically different, the Su-47, and they, like the U.S. with the X-29, found the design has many limitations when compared to more conventional fighters.