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

[SpudmanWP]

You can see that the damage goes well beyond the centerline of the PakFa by all the stuff hanging underneath.

 

[GTX]

Ouch!

 

[flanker]

In fact, it went down slightly different. Today T-50 initially rose to demonstrate the possibilities for our Indian guests. Around 12 pm on board lost contact. Was only partial remaining. On the 3rd turn there was an alarm, shavings in the right engines, the pilot was forced to shut down the right engine. Since there was no communication, he passed over the runway waving wings, letting understand the RP (EDIT: ATC) problems on board. Successfully able to land the plane on one engine. Turned to the nearest taxiway, the pilot immediately turned off the left engine. Then all the fun started! RP gave the command to leave the plane immediately. Pilot turned around and saw that intense belching black smoke poured out of the right engine. Without waiting for any ladders pilot jumped out of the cockpit. Seeing a burning puddle of fuel underneath the plane he ran a good 100 meters.

 

[SpudmanWP]

Closeups showing damage to the un-seen left side:

Look closely at the underside of the two photos. There is extensive damage to the left side of the aircraft.

Look at these closeups and at the left Levicon. I am not saying they lied about which side the fire started on, just why they didn't show the left side.

 

[Trident]

Hate to say it, but that does look like a potential write-off. At the very least, it will be a long and costly repair. It seems much of the equipment in the nose would have survived to be salvaged though, so not a total loss even if the airframe turns out to be too badly damaged for further use.

As for them not showing the other side, while there is indeed likely to be some damage there as well (for all the reasons Spudman points out) I don't really see anything which would indicate that it is worse than the right side, so I wouldn't read anything into the fact that there are no pictures (yet?). I mean, it's mildly surprising that there are decent photos so soon after the event at all!

EDIT: another interesting piece of info is that the pilot elected to unstrap and and climb out - one report on a Western pilot flying the Su-27 remarked that the intricacies of the K-36 were such that in a ground mishap it might be advisable to eject if you were in a hurry and had nobody to assist you in getting out of the harness! Maybe the new variant for the T-50 is less complicated in that regard.

 

[RadicalDisconnect]

Interestingly, the tires appear to be quite intact, so heat damage may not be all that extensive. Though the hanging fibers look quite troubling. It's hard to really gauge the damage from these photos.

 

[Avimimus]

EDIT: another interesting piece of info is that the pilot elected to unstrap and and climb out - one report on a Western pilot flying the Su-27 remarked that the intricacies of the K-36 were such that in a ground mishap it might be advisable to eject if you were in a hurry and had nobody to assist you in getting out of the harness! Maybe the new variant for the T-50 is less complicated in that regard.

Although this might be as much of a complement to the early 0-0 ejection seats that the Soviet Union helped pioneer as it is a complaint about harness complexity.

 

[donnage99]

Yet another reminder of the danger of being a test pilot and the caliber these men must have. Glad he's safe.

 

[kaiserbill]

Why is there a radiation symbol/sticker on the levcon?

EDIT: I haven't been keeping up with the latest PAKFA, especially 055, so a brief perusal on the net finds claims that the Levcon houses radar antenna.

 

[GTX]

I have seen speculation that it was an engine fire. I have to question that though since it looks to be far too forward for that. I wonder more if it was a fire in another system - perhaps avionics overheating or even OBOGS?

 

[Sundog]

I have seen speculation that it was an engine fire. I have to question that though since it looks to be far too forward for that. I wonder more if it was a fire in another system - perhaps avionics overheating or even OBOGS?

An engine fire that spread to a fuel tank? Do they (RuAF) use hydrazine? Maybe there was a hydrazine tank there?

 

[Magoodotcom]

12 posts on this so far! Imagine if it had been an F-35....we'd be at 12 pages and counting!!!

 

[donnage99]

Because unlike the f-35, PAK FA is still in a much earlier stage of development, hasn't had a track record of failed promise repeatedly over the past 20 years, and massive cost overrun that left the US air force too starved for money that the bulk of its fighters are less advanced then their export versions that are sold to allied forces. We are also talking about the scale of the project - f-35 is meant to be a core fighter component of all 3 branches of the US military for the next 50 years, and a dozen other allied military.


The PAK FA incident is sad. Will it cause some stir, especially with India? Possible. But it is hardly an incident that would be as catastrophic as say the f-35 crashed at this stage of development. And there are good reasons for that.

 

[flateric]

OBOGS is placed in quite a different place
we don't use hydrazine
rumors are of AMD fire

 

[Dragon029]

Active Missile Decoy? (Sorry, not familiar with the systems)

 

[Sundog]

OBOGS is placed in quite a different place
we don't use hydrazine
rumors are of AMD fire

Thanks for the info.

 

[GTX]

12 posts on this so far! Imagine if it had been an F-35....we'd be at 12 pages and counting!!!

I like to think of the difference between this and the F-35 is that this (landing after catastrophic failure) is a test the F-35 has yet to perform...Those darn crafty Russians…showing the west up again!

 

[kcran567]

I'm no engineer, but from the photo the fire damage is directly above the Levcon. How can that possibly be from an engine fire? Could be a Levcon actuator or wiring, or antannae component in the Levcon.

Is there an active radar wave cancellation system located near the intake openings on the Pakfa?

 

[overscan (PaulMM)]

Warning: I'm not sure we need to discuss the F-35 in yet another topic.

 

[flanker]

I'm no engineer, but from the photo the fire damage is directly above the Levcon.

No it isn't. I am also unsure what AMD is exactly?

 

[Sundog]

I am also unsure what AMD is exactly?

I think he is referring to what what we call the Accessory Drive.

 

[saintkatanalegacy]

 

[Gavin]

I've been trying to decipher the flight instruments display in the T-50. (If this really is the T-50 cockpit?)

I can recognize the ADI, altimeter, airspeed and horizontal situation indicator. And I assume that's a rate of climb/descent to the right of the ADI?

What's on the left of the ADI? Angle of attack indicator? Turn rate?

And there's a sort of inverted v-shaped gauge between the ADI and the HSI. What is that? And is it the same thing as the larger, similarly shaped display to the right of the flight instruments? Engine thrust perhaps?

 

[Granit]

What's on the left of the ADI? Angle of attack indicator? Turn rate?

AOA indicator

And there's a sort of inverted v-shaped gauge between the ADI and the HSI. What is that? And is it the same thing as the larger, similarly shaped display to the right of the flight instruments? Engine thrust perhaps?

Engine RPM in %

 

[RadicalDisconnect]

From Key Publishing, allegedly one of the earlier airframes repainted. Possibly testing out the RAM? Also note the tinted canopy.

 

[flateric]

this is T-50-KNS @RAM

 

[Triton]

"Russia to deploy fifth-gen fighters, S-500 missiles in 2016"
Published time: August 10, 2014 08:12

Source:
http://rt.com/news/179256-russia-deploy-s500-missiles/

In 2016, the Russian military will start deploying two advanced weapons, the fifth-generation fighter jet PAK FA and the long-range surface-to-air missile systems S-500, chief of the Russian Air Forces said.

Lieutenant General Viktor Bondarev gave an outline of his branch's modernization plans, including the build-up of Arctic infrastructure, in a radio interview with the Russian News Service station on Sunday.

The flight trials of PAK FA (T-50) will soon be over, and in 2016 the Air Force is planning to start commissioning the aircraft into service, the general said.

PAK FA is Russia's first fifth-generation fighter jet built by the Sukhoi Corporation. So far five prototypes have been completed and are undergoing various tests. The fighter is scheduled to eventually replace Sukhoi Su-27s.

“It took part in the [international pilot competition] Aviadarts twice and performed aerobatic flights in pair. I believe the aircraft has a brilliant future,” the general said.

Another new addition to the ranks planned for 2016 is S-500, a state-of-the-art long-range air defense system developed by Almaz Antei, Bondarev said. The producer is finalizing new missiles for the system, which would have advanced homing electronics.

“The missiles will have a build-in intelligence system, which will analyze the aerial and radar environment and take decisions about its altitude, speed and direction of the flight,” the general said.

S-500 is an advanced version of S-400 with dedicated components designed to intercept ballistic missiles at a height of up to 200 km. The system is expected to be able to shut down up to 10 incoming ballistic missiles simultaneously. It also has an extended radar range compared to S-400.

Gen. Bondarev confirmed the previously reported schedule for the development of PAK DA, a new Russian strategic bomber. So far little has been made public about the aircraft, which is to replace Tupolev Tu-95s and Tu-160s as the backbone of Russia's aerial nuclear capability. It's rumored to be a sub-sonic flying wing design and may have a new nuclear-capable cruise missile developed for armament.

The general confirmed that the Air Forces expect Tupolev to produce first prototypes of PAK DA by the end of the decade and launch series production in 2021-2022. In the meantime, modernization programs for Tu-95s and Tu-160s are enough to keep the Russian strategic bomber fleet in good shape and sufficient for the renewed long-range flight missions, he said.

Arguably the biggest modernization effort required from the Air Forces is focused on the Arctic infrastructure. Back in Soviet times the military maintained a massive network of airfields and radar stations in the north, but they were neglected in the years following the USSR’s collapse. With rich Arctic resources becoming more accessible and a potential for a conflict in the area growing, the Russian military are rebuilding the Arctic bases.

“We don't see any rivals in the Arctic now, but if a challenge comes, we must be prepared to defend this region. The presence in the Arctic will be increased,” General Bondarev said.

Russia this year reopened the Temp airfield on Kotelny Island north of eastern Siberia, the general announced. There are plans to enlarge the bases in Tiksi, Alykel, Vorkuta and Anadyr. In the future, full-strength divisions and regiments of the Russian Air Force will be deployed in the north.

 

[stealthflanker]

LEVCON vortex image by lady Stkatanalegacy :3

So basically the Levcon feeds high energy vortex to the body Thus improve maneuverability ?

 

[saintkatanalegacy]

acts like a hybrid between slats and canards that also affects yaw. bleh too complicated.

 

[Avimimus]

One important effect is that it can control pitch moment better - thus allowing a smooth transition between super-maneuverable and normal realms of flight. The differential deployment in yaw helps with spin recovery, and the additional control surfaces increase durability in case of battle damage (without having to have a canard).

 

[LowObservable]

According to the design patent, the Levcon can also recover the jet from a high-alpha position if the TV takes a poo at an inconvenient moment.

 

[RadicalDisconnect]

http://en.itar-tass.com/economy/748667

MOSCOW, September 08, /ITAR-TASS/. Russia’s Air Force does not depend on foreign components, United Aircraft Corporation CEO Mikhail Pogosyan said on Monday.
“Clearly, our military aviation must not depend on foreign supplies, and we are pursuing this policy now,” he said.
In civil aviation, the share of domestically-made components is 50% “This figure is higher when aircraft are upgraded. This [growth] happens faster now,” Pogosyan said.
UAC is planning to increase production by 30% this year, he said.
The Russian Defence Ministry has worked out a detailed plan up to 2020 for re-equipping the country’s Air Force.
“In 2016 we will start receiving the first T-50 planes,” the Air Force Commander, Lieutenant General Viktor Bondarev, adding that everything was going according to plan and the flight personnel of the 929th Chkalov flight test centre retrained for the T-50 aircraft also known as the Prospective Airborne Complexes of Frontline Aviation (PAK FA).
According to Bondarev, the pilots have already started flights on one plane, and the second one is being readied.
The first PAK FA aircraft will perform its first flight in 2019.
“In 2019, the plane is to perform the first flight, and in 2023 its tests will be completed and delivery to the troops will be carried out,” Bondarev said.
PAK FA (T-50) is Russia’s multipurpose fifth-generation fighter jet, created by the Sukhoi design bureau. The plane performed its first flight in 2010. It is a missile-carrying strategic bomber of a new generation, designed by the Tupolev company. The plane will not be a deeply modernised version of Tu-160, but will become a principally new aircraft. In the future, PAK FA is to replace the Tu-95 and Tu-160 planes of long-range (strategic) aviation that are in service in the Russian Air Force.
Russia is also upgrading its strategic Tu-160 and Tu-95 aircraft to almost double their performance.
“These planes meet all modern requirements, in principle, but they are being seriously upgraded now in order to almost double their combat performance,” he said.

I gotta say the info in this article is rather weird. Perhaps they mistook the PAK FA for the PAK DA? Can someone please shed some light on this?

 

[SOC]

Yeah, they're talking about PAK-DA there at the end.

 

[RadicalDisconnect]

At Key Pubs, a user named Jo Asakura, who seems to do some pretty thorough research on the PAK FA, state that with some kind of CNT coating on engine fan blades the aircraft will have stealthy fan/compressor face that would negate the need for serpentine inlets or radar blockers. Here are his posts, which seems to be fairly detailed.

Stealth Compressor Redux

Last week, engine producer UMPO issued a press release regarding a brand new "high temperature" aluminium alloy developed for the LP compressor fan blades of military gas turbine engines. It stated linear friction welding would be used to BLISK the stage this year, it is a codevelopment with UGATU and NPP Motor:

http://www.umpo.ru/News118_873.aspx

This is the very alloy (Al-Cu-Mg-Ag):

http://journal.ugatu.ac.ru/index.php/vestnik/article/view/772
http://www.keytometals.com/page.aspx?ID=CheckArticle&site=ktn&NM=240

Worldwide research on carbon nanotube (CNT) modification of this same alloy dates back nearly a decade*. It appears the previous UGATU/NPP Motor development I detailed a couple of years ago (CNT modified Mg-B-CFRP) has been superseded- probably because of poor fatigue life @ ~14k rpm, difficulty of 'BLISKing' and expense. Evidently, the PMC blade is not up to the task either.

The Russians have also CNT modified aluminium alloys for "aerospace, missile & space structures and components":

http://bankpatentov.ru/node/584395
http://www.freepatent.ru/patents/2487186
http://www.tpmtm.ru/en/kompetencii/26-kompoziti.html

As previously detailed, CNT modification of such materials has a highly desirable LO 'by-product' (particularly absorption in the X-band), as well as increasing it's mechanical/fatigue properties.

Interestingly, just like the preceding Mg-B-CFRP development, the aluminium alloy fan stage appears destined not only for the 'Type 30', but to be retrofitable to legacy engines (to defeat NCTR techniques?), as well as for prop/open rotor fans of UAVs.


* infoscience.epfl.ch/record/33609/files/EPFL_TH3140.pdf

...Doh!!! Missed the elephant in the room! The 'keytometals' link above refutes the description of these aluminium alloys as "high temperature".

-which "severely limit their industrial applications". However, the UMPO link describes theirs as "a heat-resistant aluminium alloy" (жаропрочного алюминиевого сплава).

This is a huge indicator that it is the application of CNT additives with their very high thermal conductivity that significantly improve the thermal (as high as 400°C) and thermo-mechanical properties of this aluminium matrix composite (and not necessarily CNT additives to the base Al-Cu-Mg-Ag alloy).

After all, they were bold enough to go for gamma titanium-aluminide for the Type 30's HP compressor and kept this intermetallic composite's R&D phase tightly under wraps. Incidentally, UMPO's 2013 company audit (the one that broke 'stage 2 PAK-FA prototypes') also stated the Type 30's LP compressor fan blades were still at the R&D stage.

Ah what the hell, let's give 'em the benefit of the doubt (moving pictures speak louder than words):

http://youtu.be/GuiE1C7eZcE
http://www.sygma.ru/metals

So, Ladies and Gentlemen, (imho) with a high degree of certainty we can call this the [making of] the World's first 'Stealth Compressor'.

The lead developer of the 'Type 30' is OKB A. Lyulka, and they have teamed with OKB Sukhoi, FGUP TsIAM and a major Russian radar design company to address the RCS tasks (aka *special characteristics*) for the Type 30. These are excerpts and pics taken from a very recent official document:

Доводка конструкции узлов включает в себя исследования специальных характеристик входного и выходного устройств на полнонатурных макетах. В ОКБ им. А. Люльки разработано методика и технология изготовления полнонатурных пакетах с широким использованием технологий прототипирования из полимерных и металлических материалов…

Запущен цикл исследований по специальным матириалам и покрытиям (в.т.ч. высокотемпературным) применяемым в конструкции перспективных двигателей. Большинство из этих материалов впервые применяются в авиастроении.

Completion of construction centres including those for studies of special characteristics of the intake and exhaust structures on high-(pole) mounted models. OKB. A. Lyulka developed a technique and technology of manufacturing pole mounted packages with extensive use of technologies for prototyping from polymeric and metallic materials …

A series of investigations was launched for the special materials and coatings (including high temperature) used in the design of advanced engines.
Most of these materials are applied in aviation construction for the first time ever.

Pic 1: 'Comparison of predictive (in green) and experimental (in black) radar wave signal scattering for a rotating body.'

Pic 2: 'Model of an engine exhaust structure during anechoic chamber studies of it's *special characteristics*'. Note what appears to be a PMC cowling.

What do people here make of these claims? I was under the impression that radar stealth is rather dependant on shaping, and compressor face isn't too stealthy due to its geometry, even if RAM coatings are applied.

 

[AeroFranz]

I seriously doubt you can make a first stage with good aero AND a blade shape effective for RCS reduction. I am pretty sure the propulsion aerodynamicist on the program would threaten suicide. Those guys have to play with airfoil shape and twist like crazy just to get the surge margin (required by the punishing inflow demands of high aoa, plus quick spool-up from idle) and good pressure rise per stage without having to worry about RCS. I think you would really give up too much performance if you followed that strategy.


Now, if you can decouple the problem and have inlet guide vanes/blocker, then the problem gets easier. It still requires careful concurrent optimization of the components, but a non-rotating vane is easier to coat with RAM.


I guess if you could coat the blades with RAM (which still has to be durable to withstand FOD), then you wouldn't have to compromise the aerodynamics and you could get some RCS reduction. I'm speaking theoretically, who knows what happens when you get into real-world manufacturing issues such as minimum thickness...


Anyway, the key point in attenuating the radar return in an inlet is to force as many bounces as possible within the duct. I can't see how you could achieve that with a straight duct and an aero-optimized fan.

 

[flateric]

With all my respect to Jo enormous search activities in support of his theories, most of them can be described as wishful thinking.
There are research and there are research. There are patents and there are patents. I've tried to convince him that his theories are overdue, but at some moment decided to stop.

 

[bipa]

Pic 1: 'Comparison of predictive (in green) and experimental (in black) radar wave signal scattering for a rotating body.'
Pic 2: 'Model of an engine exhaust structure during anechoic chamber studies of it's *special characteristics*'. Note what appears to be a PMC cowling.

'Rotating body' or 'body of revolution'? Somebody confirm the russian translation?
Experiment in Pic2 is probably more focussed on radar backscatter from external engine shapes (e.g. nozzle petals).

What do people here make of these claims? I was under the impression that radar stealth is rather dependant on shaping, and compressor face isn't too stealthy due to its geometry, even if RAM coatings are applied.

I share your impression 100%.

 

[Granit]

'Rotating body' or 'body of revolution'? Somebody confirm the russian translation?

'body of revolution'

 

[RadicalDisconnect]

I seriously doubt you can make a first stage with good aero AND a blade shape effective for RCS reduction. I am pretty sure the propulsion aerodynamicist on the program would threaten suicide. Those guys have to play with airfoil shape and twist like crazy just to get the surge margin (required by the punishing inflow demands of high aoa, plus quick spool-up from idle) and good pressure rise per stage without having to worry about RCS. I think you would really give up too much performance if you followed that strategy.


Now, if you can decouple the problem and have inlet guide vanes/blocker, then the problem gets easier. It still requires careful concurrent optimization of the components, but a non-rotating vane is easier to coat with RAM.


I guess if you could coat the blades with RAM (which still has to be durable to withstand FOD), then you wouldn't have to compromise the aerodynamics and you could get some RCS reduction. I'm speaking theoretically, who knows what happens when you get into real-world manufacturing issues such as minimum thickness...


Anyway, the key point in attenuating the radar return in an inlet is to force as many bounces as possible within the duct. I can't see how you could achieve that with a straight duct and an aero-optimized fan.

Are the inlet guide vanes the radar blocker? I'm not sure about that, because if the alleged insider leak of the isometric drawing is true, then the real blocker has some kind of structure that has a bunch of concentric rings.

And I'm not sure what exactly Jo's argument is now, since he is now pointing to the inlet guide vane as the radar blocker. Anyways, here are his responses to me.

It is an integrated solution*. You can do the research for temperature, Young's modulus, creep, damping etc.etc. CNT-Al nanocomposite covers all bases for the military LP compressor, comfortably outperforming Ti- this would not be the case if it was a conventional alloy. Not only is one of the co-developers a major player in CNT research, but ROSNANO itself is a major partner with UMPO for upcoming nanocomposite utilisation in military aircraft engines:

http://www.umpo.ru/News118_756.aspx

ROSNANO are the partners and the sponsors of the 'Sygma' video above.

Thus far CNT-Al has been the missing link. Combined with 'Asakurius Duckius' ®, it is nothing short of a 6G solution.

* http://forum.keypublishing.com/showthread.php?126959-The-PAK-FA-News-Pics-amp-Debate-Thread-XXIV&p=2125742#post2125742

...Oh, there was one other missing link. In the short and sharp S-duct, guide vanes are required to facilitate pressure recovery to the first stage fan. I have claimed (to the consternation of some) that in the official patent 'Device 9' (Устройство 9) which, remember, only "partially obscures" and is offset from the compressor- has a dual function of a guide vane and 'blocker'.

Evidence/precedent of this dual function?....Yip:

The text reads " Inlet Guide Vanes. Development of layered reinforcing carbonfibre (i.e CNT) package, providing absorption of radar waves".

C/o fimv.

Side note, I find it rather pompous that he's naming the PAK FA inlet after his Key Pubs username.

 

[quellish]

The text reads " Inlet Guide Vanes. Development of layered reinforcing carbonfibre (i.e CNT) package, providing absorption of radar waves".

Which mean, electrically, these are similar to the F-117 inlets. Which is a clever solution.