what is the difference between Su-35S and J-11B?

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16 years

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inspired by Deino's post..

major change of Su-35S from Su-27 is:
new PESA radar
new engine 117S with thrust vectoring
removal of air brake
more use of titanium in structure, longer life
new cockpit

major change of J-11B from Su-27 is:
new mechanical steered array radar
new cockpit with 5 mfds
new MAWS
supposedly WS-10 engines, but Huitong site says quality sucked so still using the same Russian ones.

anything else? how about J-15?

Original post

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One is the original article and the other is a gross violation and outright theft of intellectual property rights.

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New EW suit on the Su-35, as well as laser/launch warning detection.
New OLS.

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13 years 2 months

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I think the first batch of J-11Bs used Al-31s (two, three years ago?). All the ones since then have been using WS-10.

http://cnair.top81.cn/fighter/J-11B_WS-10a.jpg

And one of the biggest changes for J-11B is being able to use indigenous weapons. That was basically why it was conceived in the first place.

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Are there any plans to add radar blockers in Su-35's intakes?

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Are there any plans to add radar blockers in Su-35's intakes?

No. But Sukhoi and associated groups did a lot of work in regards to Su-27 RCS reduction. Apparently some of that was integrated onto the Su-35, I am not sure what levels though.

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From huitong's page, a full list of the J-11B's changes:
New mechanically steered radar.
Rear UV band MAWS
New cockpit
More use of composite materials
Use of RAM in specific areas (?)
Powered by WS-10
And being able to use indigenous weapons, of course.
--
Not sure if the IRST is the same as on the flankers the PLAAF got in the early 90s (his site says it's indigenous as well but not sure if it's a direct copy or if it's different), and some people are talking about an AESA replacement later on but best to leave that out for the moment.

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They are not the same plattform to start. J-11B is the older Su-27 but assembled with Chinese produced (copied) components, inherently stable airframe. Difference from Su-27: basically the same, but with different, though similar, avionics arrangement, and with different manufacture quality (worser).

Su-35 is different airframe, unstable (5-10%?) and with a very different system arrangement (avionics, etc). Manufacture is different as well.

Compare J-11B with their common plattform, Su-27, older. With Su-35 is nosense, as it is different.

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The biggest change of the J-11B is one that almost everyone seems to overlook. There was a 700kg weight reduction from the Su-27SK, which was already the lightest flanker variant. One of the rare instances in aviation when an development fork managed to shed mass.

The J-11B has a empty weight of 15680kg, thats nearly 3000kg less than the it's portly cousins derived from the Su-30. That is going to provide a major improvement across the entire flight envelope.

There was also a modest RCS improvement as well.

There is an oft repeated misunderstanding about the WS-10A engines, the "quality" issues that cropped up were not what most people think they are, and certainly not by the China Weak!11!1! crowd. Engine components have to be built to exceedingly tight tolerances and any weaknesses in production quality control shows up in a high rejection rate. The problem with the initial production of the WS-10A was that a higher number of components ended up being rejected than anticipated. This causes two issues, one a much higher cost as those parts that are rejected are still as expensive as ****, and two a lower production rate as you simply dont have enough parts needed to assemble the engines and provide service spares. The economics behind it are very similar to microchips. Each silicon wafer can produce a set amount of chips. Imperfections in the manufacturing process reduce the amount viable chips that each wafer can yield, the effect is more pronounced the larger the overall chip needs to be. This costs can be so great, that they can effectively torpedo a program as happened to the 32nm migration for Nvidia and ATI.

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The biggest change of the J-11B is one that almost everyone seems to overlook. There was a 700kg weight reduction from the Su-27SK, which was already the lightest flanker variant. One of the rare instances in aviation when an development fork managed to shed mass.
.

1.) the Su-35 is ligher than the SK.

2.) Given the replacement of legacy heavy Soviet electronics, that's honestly not that impressive.

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1.) the Su-35 is ligher than the SK.

2.) Given the replacement of legacy heavy Soviet electronics, that's honestly not that impressive.

He didn't even write a single word about Su-35 in his post. Don't get so defensive. :)

By the way, 3 tons difference is quite a lot in my opinion. It cannot be explained only by avionics.

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1.) the Su-35 is ligher than the SK.

2.) Given the replacement of legacy heavy Soviet electronics, that's honestly not that impressive.


WRT 2) huitong's site seems to imply 700kg was lost due to use of composites alone?

PKoschei, where'd you get the number for J-11B's empty weight from?

He didn't even write a single word about Su-35 in his post. Don't get so defensive. :)

By the way, 3 tons difference is quite a lot in my opinion. It cannot be explained only by avionics.

To be fair he wasn't being defensive, Pkoschei said it was rare for J-11B to be lighter than an aircraft it was developed from (Su-27), so the Su-35 being lighter than SK is quite relevant.

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He didn't even write a single word about Su-35 in his post. Don't get so defensive. :)

By the way, 3 tons difference is quite a lot in my opinion. It cannot be explained only by avionics.

Nobody is defensive. I was stating facts.

EDIT: Blitzo already caught it.

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The J-11B airframe is a modified and lightened J-11A which was a license produced Su-27SK. Which according to wikipedia has an empty weight of 16380.

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13 years 2 months

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^ Yes, but where did you get J-11B's empty weight of 15680 from?

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One is the original article and the other is a gross violation and outright theft of intellectual property rights.

This! makes all other differences irrelevant.

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Hmm.. let's se Su-35 will have the Ibris-E PESA, right? But how mouch do we know about the corresponding radar in the J-11Bs?

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SK weighs some 16 tons. su35, according to sukhoi.org weighs some 18 tons. That is only natural considering the new version has twice the lifespan and reinforced airframe for greater payloads (due to multirole missions)

Su-35S:
Weight reduction (Not clear what the baseline is, may be the old Su-27M?)
Internal structure improved for heavier payloads (8000kg) and longer life (6000h)
Third hardpoint on each wing
Comprehensive range of air to ground PGMs
Some composite panels in fuselage spine and access hatches
Digital FBW system rather than analog
Modern INS (ring-laser gyro, IIRC) and GPS/GLONASS receiver
On-board oxygen generation system
In-flight refuelling probe and wet underwing hardpoints for 2000l external tanks
New cockpit with wide-angle HUD and two 15 inch MFDs, new HOTAS grips
Fibre-optic avionics network
New radar (Irbis PESA) and IRST
New digital RWR/ESM
Spherical coverage LWR and infrared MAWS
New ECM pods (not revealed yet)
Low-intensity night formation-flying lights
New engines with increased thrust (14500kg), longer life, FADEC and TVC
New ("Link-16 type") datalink
RCS reduction: RAM coatings on leading edge parts, treated canopy, frangible gun muzzle cover
Airbrake deleted, replaced with expanded fuel capacity
Possibly no brake parachute anymore?

In short, apart from its shape and some common structural parts it is pretty much *nothing* like your father's old Flanker ;) It's even more advanced than the Su-30MKM, quite apart from having a much better thrust to weight ratio.

J-11B (somebody correct me if I'm wrong):
Weight reduction (though see below)
Longer service life
Integration of Chinese weapons (no PGMs though AFAIK)
Some composite parts (again, see below)
Digital FBW system rather than analog
Modern navigation system
On-board oxygen generation system
New radar (Mechanically scanned, planar slot array antenna)
New digital RWR
Rear-hemisphere optical MAWS
New cockpit with wide-angle holographic HUD and 3+ MFDs
Low-intensity night formation-flying lights
New engines with increased thrust (13200kg) and FADEC
RCS reduction?

Certainly a more extensive upgrade than the Su-27SM, but not really in the same league as the Su-35S. To that end, it would be interesting to compare prices...

The biggest change of the J-11B is one that almost everyone seems to overlook. There was a 700kg weight reduction from the Su-27SK, which was already the lightest flanker variant. One of the rare instances in aviation when an development fork managed to shed mass.

The J-11B has a empty weight of 15680kg, thats nearly 3000kg less than the it's portly cousins derived from the Su-30. That is going to provide a major improvement across the entire flight envelope.

That might be because people are sceptical about the veracity of this claim, and with good reason. You see, the skin panel lines of the J-11B are more or less identical to the J-11A/Su-27 (far more so than the Su-35S), indicating that the internal structure is also at least geometrically very similar. Now, that is not a smoking gun that the materials and construction are identical of course, but it does indicate that the modifications can't have been very deep.

You don't get a 700kg reduction merely by replacing metal skin panels with composite parts, even if you do so on a large scale - this approach throws away much of the potential weight saving to be had from composite construction. It also makes the use of composites in the internal primary structure doubtful, this is very advanced and if they didn't even bother to change the external panels how likely is it that they went to such lengths internally? While this is an inaccurate method (some manufacturers are known to completely coat their airframes in primer, with no distinction between metal and composite areas), photos of unpainted J-11Bs do not seem to confirm extensive composite use either.

So, there might be some composites and there might be a weight reduction - but IF the latter really is 700kg (somewhat doubtful) it won't be from the composites alone.

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15 years 3 months

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what is the difference between Su-35S and J-11B?

Simply, there are way too many unknowns with the J-11B

Some of my old stuff - Link-1, Link-2, Link-3

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16 years

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OK gents, her comes the Idiot Question of The Day: Why didnt the Chinese try to clone their Su-30MKKs instead of the more basic Su-27/J-11A??