Sukhoi Su-57 / T-50 / PAK FA - flight testing and development Part II [2012-current]

[Trident]

I wasn't talking about thermal issue, and neither did Mikhailov directly atleast.

Effectively he was - dynamic pressure is more of an issue at low altitudes, where supercruise (and speeds in the Mach 2.0 ball park) are out of the question.

Sure, with the right engines and materials. I don't see the T-50 sporting a pair of F119s anytime soon, nor does Russia have the huge industrial base to tap from when it comes to composites expertise.

Quite - I'd assume the requirements were defined on the basis of the aircraft having its definitive engine. As for composites, it is true that Russia has not put an aircraft like the Typhoon into mass production, but generally their capabilities are better than most give them credit for. Trivia moment: what was the first production fighter with composite inlet ducts?

EDIT: it is also worth noting that the T-50 vertical tails look as though they might well be made out of SPF/DB titanium, rather than composite...

 

[flanker]

Effectively he was - dynamic pressure is more of an issue at low altitudes...

That sums it up, thanks.

Trivia moment: what was the first production fighter with composite inlet ducts?

MiG-29?

 

[Trident]

MiG-29?

Exactly. Only the first several dozen airframes or so, but it is what it is and does pre-date the F-22 and F-35 by literally decades! There is very little in the way of composite technology that Russia has not at least investigated in great detail - as I said, they are far better at this stuff than they are generally given credit for.
I think some people are mislead by Sukhoi's generally very conservative material choices on the Flanker family - the MiG-29 (even the later models) in particular made more extensive use than anything contemporary from the West bar the Hornet and Harrier II, whereas the Tu-204 compares well with anything contemporary out of the Boeing stable (i.e. prior to the 777). Then there's more obscure stuff, such as satellite structural components, rocket payload fairings and interstage parts, ICBM/SLBM motor casings, Buran structural beams, the Su-47 aero-elastically tailored wings, D-18T fan stators, Ka-50 internal load-bearing structure and rotors, D-27 propfan blades, PS-90A turbofan nacelles, cryogenic tanks for aerospace planes, An-70 empennage torsion boxes... ALL of which at least saw hardware being ground tested, the vast majority even flew and most of it has been in production for more than 20 years.

 

[Radical]

I'm actually a bit curious about why the T-50 use intakes with variable ramps. I recall the pressure recovery advantage of these intakes only become significant at speeds above M1.8. This doesn't really corroborate the supposed M2.1 max speed. Unless the T-50 is optimized for supercruise speeds above M1.8, it just seems like additional weight, complexity, and RCS complications. Perhaps these intakes are meant to be a stop-gap for the current 117 engines until Product 30 is ready?

 

[Sundog]

I'm actually a bit curious about why the T-50 use intakes with variable ramps. I recall the pressure recovery advantage of these intakes only become significant at speeds above M1.8. This doesn't really corroborate the supposed M2.1 max speed. Unless the T-50 is optimized for supercruise speeds above M1.8, it just seems like additional weight, complexity, and RCS complications. Perhaps these intakes are meant to be a stop-gap for the current 117 engines until Product 30 is ready?

It could be because fixed inlets can be more complex than people give them credit for since they can bleed air from the inlet through porous materials, or some sort of fluidic controls. It's simply that, for the performance Sukhoi was looking for, they decided they could meet the requirements using ramps instead of fixed inlets. Something else I haven't seen is whether or not the inlets have screens in them for for rough field use, like the Flanker has in it's inlets. If so, I doubt there would be much reason to go to a fixed type inlet.

 

[Trident]

I'm actually a bit curious about why the T-50 use intakes with variable ramps. I recall the pressure recovery advantage of these intakes only become significant at speeds above M1.8. This doesn't really corroborate the supposed M2.1 max speed. Unless the T-50 is optimized for supercruise speeds above M1.8, it just seems like additional weight, complexity, and RCS complications. Perhaps these intakes are meant to be a stop-gap for the current 117 engines until Product 30 is ready?

That's exactly the kind of reasoning a number of people here have been putting forth. As you say, it is possible that the variable intakes are an interim solution, tied to the current engine, though.

People supposedly in the know keep saying the final version of the T-50 will change very little (down to the definitive engine retaining the same nozzles as the current one) however, so make of that what you will.

 

[Avimimus]

It may seem an odd comparison, but the Su-25 achieves its maximum turn rate (in degrees per second) at about 750 km/h (a little under Mach 0.7). The A-10 achieves its maximum turn rate at about 300 km/h.

Designing aircraft isn't just about maximising speed on the straight-away. For instance, I wouldn't be surprised is the Russians were willing to sacrifice a considerable amount of top speed in order to increase fuel efficiency in super-cruise (thus allowing greater overall mobility, with a slower dash).

 

[flateric]

Something else I haven't seen is whether or not the inlets have screens in them for for rough field use, like the Flanker has in it's inlets. If so, I doubt there would be much reason to go to a fixed type inlet.

They have clamshell-shaped screens, web-like composite structure a-la Concorde Olimpus nozzle thrust reverse petals.

 

[Radical]

Something else I haven't seen is whether or not the inlets have screens in them for for rough field use, like the Flanker has in it's inlets. If so, I doubt there would be much reason to go to a fixed type inlet.

They have clamshell-shaped screens, web-like composite structure a-la Concorde Olimpus nozzle thrust reverse petals.

They, meaning the Su-27 or T-50?

 

[flateric]

Later one, of course.

 

[saintkatanalegacy]

Refer here: http://www.secretprojects.co.uk/forum/index.php/topic,15626.msg181659.html#msg181659

and here: http://img-fotki.yandex.ru/get/5630/167229822.23/0_b93b0_526f7739_L.jpeg

 

[sanjeev.k]

People supposedly in the know keep saying the final version of the T-50 will change very little (down to the definitive engine retaining the same nozzles as the current one) however, so make of that what you will.

So, does that mean the type-30 engine will not even have F-35 style serrations on its nozzles?
I find it a bit odd that Sukhoi paid attention to shaping the rear beavertail between the engines, for stealth, but nothing for the nozzles.

 

[Sundog]

I have a general question regarding these FOD screens. Is there a slot near them that allows the FOD material stopped by the screens to be dumped from the nacelles? Does it get blown around through a bypass section? Or do the screens just hold onto it until after the plane lands and they can be cleaned out?

 

[flateric]

Downward FOD extraction slot is mentioned in patent application but seen nowhere on actual a/c (so far)

 

[Sundog]

Thanks, that was one of those things I never really thought about until now.

 

[EricChase88]

http://www.russiadefence.net/t183p870-pak-fa-t-50-news

"If you can understand Russian, you would learn that PAK FA has exceeded its developers expectations in the fields of supermaneurability and supercruise speed.
Commenting journalist has stated that PAK FA is much lighter than F-22 and its maximal speed is 500 km/h greater than F-22.
It is unknown, what speed has he talked about, afterburned max or supercruise speed. It is possible that this is his own fake addition, but bearing in mind the official status of those video it is unlikely.

Data is short, almost none actually. However progrm-outside experts have calculated that if the PAK FA empty weight is 3 tons less than F-22, then T-50 can reach 2100 km/h supercruise speed using the current 117 engines. This is indirectly confirmed by Mikhail Pogosian. He has stated that Sukhoi company is completely satisfied with 117 engine performance and the engine completely complies all the 5-gen fighter engine requirements on thrust, specific thrust, resource and speed/altitude params.

Also guys from KNAAZ say that T-50-6 and T-50-7 prototypes are in the middle-construction phase now. T-50-7 will not be flyable.
Experts oppinions on T-50-7 purpose has separated to 2 points:
1 - T-50-7 is an RCS measurment and optimizations body.
2 - T-50-7 is another one prototype frame for resource testing while the previous prototype testing gave a lot of data to improve airframe strength and optimize weight. It is also rumored that CM part in the future prototypes and LRIP planes bodies will be significally increased, so they will be tested on T-50-7.

There are the other facts about static version:
1 - T-50-4 has enforcement plates on several parts and those plates must be removed and replaced by internal body strength improvements.
2 - As T-50 has exceeded initial speed parameters, then they must be utilized by more robust body allowing to withstand long 2650 km/h (2.35M) flights."

 

[flanker]

Also guys from KNAAZ say that T-50-6 and T-50-7 prototypes are in the middle-construction phase now. T-50-7 will not be flyable.
Experts oppinions on T-50-7 purpose has separated to 2 points:
1 - T-50-7 is an RCS measurment and optimizations body.
2 - T-50-7 is another one prototype frame for resource testing while the previous prototype testing gave a lot of data to improve airframe strength and optimize weight. It is also rumored that CM part in the future prototypes and LRIP planes bodies will be significally increased, so they will be tested on T-50-7.

Third hand (!) source reading gives inaccurate information like this... Reading directly from the actual source* would reveal what T-50-7 is for. No need for "expert opinions" (lulz) then.

T-50-1:

http://www.youtube.com/watch?v=RvzIOgylEnE

* I can't verify sources authenticity 100 %. However, judging by his posts regarding Su-35S and SSJ he seems to be real deal.

 

[Radical]

http://www.russiadefence.net/t183p870-pak-fa-t-50-news

"Data is short, almost none actually. However progrm-outside experts have calculated that if the PAK FA empty weight is 3 tons less than F-22, then T-50 can reach 2100 km/h supercruise speed using the current 117 engines. This is indirectly confirmed by Mikhail Pogosian. He has stated that Sukhoi company is completely satisfied with 117 engine performance and the engine completely complies all the 5-gen fighter engine requirements on thrust, specific thrust, resource and speed/altitude params.

I don't quite follow. Basically, Pogosyan states that 117 engine meets performance requirements (which is a fact). Then this somehow is confirmation of 2100 km/h supercruise speed. I'm not seeing the connection here. And who are the "program-outside" experts? Also, I thought weight doesn't make too much difference in supersonic drag, so I'm not quite sure how they get the 2100 km/h figure to begin with.

There are the other facts about static version:
1 - T-50-4 has enforcement plates on several parts and those plates must be removed and replaced by internal body strength improvements.
2 - As T-50 has exceeded initial speed parameters, then they must be utilized by more robust body allowing to withstand long 2650 km/h (2.35M) flights."

Also, where did 2650 km/h figure come from?

 

[flanker]

Read through last pages and you shall find out.

 

[sferrin]

There are the other facts about static version:
1 - T-50-4 has enforcement plates on several parts and those plates must be removed and replaced by internal body strength improvements.
2 - As T-50 has exceeded initial speed parameters, then they must be utilized by more robust body allowing to withstand long 2650 km/h (2.35M) flights."

Also, where did 2650 km/h figure come from?


Basically they were just saying if they wanted to go that fast for any useful amount of time they'd need new materials. They weren't saying that it could.

 

[saintkatanalegacy]

Side looking array: N036B-1-01L/ -01B NIIP AESA

371 T/R modules

http://www.ng.ru/armament/2013-08-16/5_niip.html

 

[F-14D]

Good design analysis by Bill Sweetman in current issue of Aviation Week.

Updated with URL: http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_08_19_2013_p43-605528.xml

 

[Dragon029]

They're already pulling cobras in the PAK FA?

http://www.vesti.ru/only_video.html?vid=531660

Starts at 1:25.

I find it somewhat hard to believe that they'd be doing that kind of action this early (with only 3 airframes!), but on the other hand, if it's CGI, it's very well done.
Also there's the point of it's agility; that pitch up was ridiculously fast; almost unbelievably so...

 

[Avimimus]

The rate at which they've been expanding the envelop shows a great deal of confidence - the early demonstrations to officials showed low altitude steep turns with more than thirty degrees angle of attack (within a couple months of the first flight). Some of the recent footage already shows super-maneuverability in the yaw axis being tested...


In the footage - is it rolling while pulling the cobra??

 

[overscan (PaulMM)]

Pretty sure its getting ready for MAKS 2013. Expect them to push it very hard.

 

[LowObservable]

Stout shoes, check... Cyrillic decoder ring, check... Pentothol martini mix, check....

 

[flateric]

Take umbrella, raincoat and panama

 

[F-14D]

The rate at which they've been expanding the envelop shows a great deal of confidence - the early demonstrations to officials showed low altitude steep turns with more than thirty degrees angle of attack (within a couple months of the first flight). Some of the recent footage already shows super-maneuverability in the yaw axis being tested...


In the footage - is it rolling while pulling the cobra??

IMO, one of the ways Russia and the West have diverged over the past few decades is in the goals of flight testing. The Russians apparently still look at it as part of development, exploring the envelope, determining the limits and finding what needs to be changed. For the US and arguably England and France, it's about reducing risk. As a result, they seem more "aggressive".

 

[flanker]

They're already pulling cobras in the PAK FA?

http://www.vesti.ru/only_video.html?vid=531660

Starts at 1:25.

I find it somewhat hard to believe that they'd be doing that kind of action this early (with only 3 airframes!), but on the other hand, if it's CGI, it's very well done.
Also there's the point of it's agility; that pitch up was ridiculously fast; almost unbelievably so...

It is pulling more impressive stuff that cobras. And of course it is real. There are 6 finished frames, 4 of which are flying.

 

[EricChase88]

They're already pulling cobras in the PAK FA?

http://www.vesti.ru/only_video.html?vid=531660

Starts at 1:25.

I find it somewhat hard to believe that they'd be doing that kind of action this early (with only 3 airframes!), but on the other hand, if it's CGI, it's very well done.
Also there's the point of it's agility; that pitch up was ridiculously fast; almost unbelievably so...

It is pulling more impressive stuff that cobras. And of course it is real. There are 6 finished frames, 4 of which are flying.

That looks incredible. A testament to the plane's amazing maneuverability.

 

[flanker]

According to Bogdan it is only able to show about 40 % of its potential...

 

[FighterJock]

According to Bogdan it is only able to show about 40 % of its potential...

I wonder what it's full potential will be like once it enters service.

 

[F-14D]

...I wonder if we can get Clint Eastwood to steal one for us. ;D

 

[FighterJock]

...I wonder if we can get Clint Eastwood to steal one for us. ;D

It probably wouldn't work out in reality. By the way, Firefox was the initial spark that made me get interested in Military Aviation way back in the 1980's.

 

[F-14D]

...I wonder if we can get Clint Eastwood to steal one for us. ;D

It probably wouldn't work out in reality. By the way, Firefox was the initial spark that made me get interested in Military Aviation way back in the 1980's.

Besides, Putin would say he'd fly the 2nd prototype in pursuit himself.


...without a shirt.

 

[Dragon029]

...I wonder if we can get Clint Eastwood to steal one for us. ;D

It probably wouldn't work out in reality. By the way, Firefox was the initial spark that made me get interested in Military Aviation way back in the 1980's.

Besides, Putin would say he'd fly the 2nd prototype in pursuit himself.


...without a shirt.

Along with bears for wingmen, whom Putin simultaneously wrestled into submission and taught to fly and fight.

 

[flanker]

...I wonder if we can get Clint Eastwood to steal one for us. ;D

"Think in Russian" ;D

 

[EricChase88]

According to Bogdan it is only able to show about 40 % of its potential...

I wonder what it's full potential will be like once it enters service.

The airplane will be incredible. When it get second stage engines it will be a true symbol of the sheer brilliance of Russian engineers.

 

[Kryptid]

Also there's the point of it's agility; that pitch up was ridiculously fast; almost unbelievably so...

Normally, a designer will avoid overly large strakes because of the poor pitch-up tendencies they can produce. With the T-50, it actually looks as though they are taking advantage of that same fact to generate the quick nose-up motion we see. The ability of the LEVCONs to move downward allows the aircraft to control pitch-up so that it doesn't get out of hand. That's actually rather clever...

 

[Radical]

Isn't T-50-5 suppose to fly before MAKS? Also, are structural refinements completed yet?