Su-35S: News #2

Very interesting article about the Su-35's sensor fusion system.
https://bmpd.livejournal.com/3047341.html

TMA1 wrote:You can see an arrow and degrees of motion

Good spot by you!  I hadn't noticed the arrow even though it was kinda clear.  Makes sense, too.  That point would be exactly where the horizontal stabilizer would be at its level setting.  Point zero, so to speak.

I bet they use that super cool, old-fashioned levelling meter thingamajig thingy lol that clips on moving surfaces they use during production to find that center level point.  I remember seeing it in one of the Su-35 production videos when one of the technicians had it mounted on the edge of one of the flaperons.  As the flap would more up or down, the needle on that tool would also move and point at all the incremental settings.  That's one of those original tools that never loses its usefulness despite all the modern advancements in technologies.  I have a few of those in my trade I pull out every once in a while, and all the younglings on site start ragging on me with their digital laser ultraviolet see-through high-tech smart tools that cost zillions to buy (which I also have anyway lol) but my $3 tool ends up being faster, more convenient, problem-solving and just as accurate in certain cases lolzo.  Love that stuff.  

Mir wrote:Its a faint permanent marking - and yes it shows the extend of the stabilizers motion.

Perfect photo.  At first when I noticed the mark and the possibility of it being exactly that with all the incremental markings, it reminded me of waterline & draft measuring markings they put on the hulls of ships and even submarines.  

But I've never seen it applied to aircraft like this to obviously measure the stabilizers proper alignment which is beyond cool.  Something you really don't see often, if at all and especially in this modern-day, tech-filled industry.

Mir wrote:Any contact with the airframe could be catastrophic as was the case with early Mig-25's. Early on the Mig-25 suffered a couple of nasty accidents when the aircraft suddenly rolled and turned into a steep dive. It was eventually discovered that the stabilizers jammed and the problem was rectified!

Thought the same exact thing which is what I was hoping that it was not a scratch or an undesired point of contact!  That would NOT be good and also 99.99999% unlikely.

Pretty much why aircraft are built with the most stable alloys & composites possible; to reduce the inevitable effects of expansion & contraction in designs that require incredibly minimal tolerances between moving surfaces, and for something like that MiG-25 scenario from never happening again or in the first place.

That also reminds me of the one time I was at an airshow and was snooping around under an active USAF B-1B Lancer on static display (we're allowed to do that BTW lol) and I was astonished at how much fuel was leaking below the engine nacelles and onto the tarmac where they had cordoned people off with caution tape for obvious safety reasons.  But the amount of staining in the two puddles on the ground and that unmistakably familiar scent of kerosene was mind-blowing to the point I thought there was either a fuel leak problem or the crew that was fueling the aircraft had spilled some for whatever reason.  So I asked one of the pilots who was talking to visitors and answering question what the heck all that spilled fuel was talking to visitors and to my surprise, he said it was the result of expansion & contraction in the fuel cell panels from the stress of subsonic to transonic to supersonic speeds and back & forth.  Amazing and apparently a common occurrence in not just that particular aircraft.

I have pictures of it somewhere I'll try to dig them out.  It's wild but all this sshhttuufff reminded me of that.

AMCXXL wrote:
This is 5 years 2024 to 2028 or at least 60 more Su-35 for VKS, perhaps even 80
I think 200 is the rigth number for VKS

Well if you add the upgraded Su-30SM2's...the numbers sounds even better!

He means "MiG-31 to be replased by PAK-DP"...

Mir wrote:
Its a faint permanent marking - and yes it shows the extend of the stabilizers motion.

I can't find the gaddang pics of the B1 bomber with the leaking engines.  But I just saw this on X and it reminded me of this conversation.  Same thing for that H-stab.  I just found it interesting that Sukhoi has that on its brand-new Su-35S in this particular case.  Maybe gives the true meaning of IOC, emphasis on the I for "Initial," perhaps?

That type of marking is quite common - mainly for ground crew inspection.

Some samples on Sukhoi aircraft:

Su-24


Su-27


Su-33

Mir wrote:That type of marking is quite common - mainly for ground crew inspection.

Some samples on Sukhoi aircraft:

Su-24

You are correct again, sir.  I asked my buddy who is former USAF and he told me that while he's not fully familiar with Soviet or Russian specific aircraft labeling, he did know some of the maintenance procedures based on his experience with ex-Warsaw countries' air forces and their Russian jets he was able to see up close (Su-27 & MiG-29 to be specific) and that those are in fact not just for testing, but for the maintenance crews to periodically check, like you said.  

I asked check for what? He said (and these were his words) it's similar to an automatic transmission in a car, or even timing on engine ignition where you have tap-dead center as a reference to idle or a neutral setting, and that the FBW when given a stick cue to return to neutral and there are 2 surfaces that need to be in completely perfect sync, that is how you determine if they are.  Not only when they return to that neutral setting (the center arrow), but when rotating for takeoff for example.  They need to both reach the exact setting.  Or even for differential settings for roll.  Each stabilizer has to be exactly at the correct setting for the commanded FBW instruction and by looking at them in those positions, they can determine if on or the other or both are working properly or if something is off.  I know this stuff might be silly to some, but I find it fascinatingly interesting!

Here's some synchronized perfection.