View Single Post
Old Nov 19, 2012, 03:54 PM
PeterVRC is offline
Find More Posts by PeterVRC
Registered User
Australia, VIC, Melbourne
Joined Nov 2006
13,913 Posts
The Su-35 finally took to the air once again......
Unfortunately over recent months it has been eclipsed by the awesome Dynam Me-262 so the Su kept getting left aside. And the return to the air today wasn't overly inspiring for the Su.....

One good thing - probably due to raising the nose gear via spacer blocks - is that it took off within the 22metres of the cricket pitch length! And a nice gradual rise too! So I didn't even need to do anything special.
I actually took it to the very end of the cricket pitch, to get every CM possible, with near zero belief it would probably even get airborne - because if it runs out of pitch and gets to the grass it would slow it down too much - and I just said "I am just going for it, and if it runs onto grass (which I expected it would) I will just keep going until it looks bleak and heading to the fence!". Not that I wanted to hit the fence, but you have to give it the distance to even have a hope to get aitborne and by then you aren't going to be stiopping by the fence either! It MUST fly or there will be tears! Which the past flight did get airborne in time - though I started from half way to the other side fence first!

But it was all a big surprise and non-event!!!
I had to go to WOT instantly, to maximise the speed reached in the 22metres. A 2m wide strip and that was no issue to direction, it tracked dead straight fine.
I thought I was going to need some "elevator flick" but before I even got to that point I could see it was rising anyway! I would say the wheels left the deck with a few metres to go, maybe 3m, so the total runout to lift off would have been about 18metres.

As it climbed away - with a slight move to steeper climb rate, to clear trees off the edge of the oval, when I went to level out I found to fly level it needed just over 50% UP elevator! In the take-off excitement I hadn't noticed anything - but interesting that it took off like that!! I think what happened was it took off ok, and once airborne I was real-time flying it to do the climb I wanted, thus of course over-rode the trim issue without even knowing that.
When I let the stick to mid position is dived sharply! Full up trim just got it to fly level!

It didn't fly that well. It was tail dragging through turns. And any banking turn over 40deg or so would turn it into a 'severely falling' aircraft! Not linear as to bank angle, but as if past a certain angle was a cliff.
It was not much fun to fly..... but I did a few tests and then landed. No flaperons or spoilers used and it landed beautifully to scale - still using some % of throttle, maybe 5% to 10% stick?

When I brought it back to the runway.... OH.... flaperons were half way down ALL the time!! ooops. The Flaperon Pot was not dialled back to its zero position, and I had not even noticed that when it was on the runway before!

So what does that mean???
1) Made the plane pitch down a lot.... and needed 8mm of elevator front tip downwards positions (compared to their neutral setup line).
2) Took off very well !!!

That doesn't seem to add up. I would have thought they would IMPEDE take-off!!

So for the next flight I dialled out the Flaperons, of course, and took 4mm of the elevator trim out - leaving some in case it needed it.
The take-off was identical......
The 4mm of up elevator trim was approx correct, so now it showed it was nose heavy - as well as before being 'Flaperon Down Pitched'.
It still dragged the tail down through turns... and "fell" notably on severe banked turns.

I decided (I guess) that the tail dragging turns are because it is nose heavy and the notable up elevator trim for neautral is causing that.
The falling out of turns.... probably half normal, and half due to being nose heavy.
Though I did not balance it so I don't truly know what the CofG was at all.

When I tested "Flight Mode 2 - mixed elevators and ailerons" (they operate in every combination of helping each other) it was very twitchy! So it helped manoueverability a lot, but it wasn't any use trying anything then as it was flying so 'floundering-like' anyway.
I forgot to go back the FM1 for landing!! So that made it fun on the initial approach until I got more tuned in to the sensitivity! Then remembered the FM2 setting after landing.....
PeterVRC is offline Find More Posts by PeterVRC
Reply With Quote