toothpick

i have a super air 46 .
Most times that i do loops with full up elevator the model starts to roll on the downward leg of it .
Does anyone else have this problem or think they know how to fix it ?

TomCrump

Try reducing your elavator throws.

toothpick

i have tried that but only by 10 % and it still did it

TomCrump

Try reducing it some more. I've experienced this same problem, and it worked for me.

toothpick

yeah i'll try that and if that doesn,t work do you know any thing else that might work ?

majortom-RCU

My Feedback: (40)

Lotsa times people work the elevator stick and it inadvertently wanders into the aileron axis. Does it roll if you use thumb and finger on the elevator? Do you have expo on the ailerons?

What kind of control system do you have on elevator? Could be your system applies more movement to one elevator half than the other.

toothpick

The prob with sayin that is that i fly a different control system to what you do i fly a system called mode 1 yours is called mode 2 the difference is that my elevator and throttle are on the other side so on my left thumb i have elevator and rudder and on my right throttle and ailerons . so what do you think the prob might be ? [&:]

Stickbuilder

And some model aircraft (and full scale as well) exhibit pitch/roll coupling inherently, and there is not much to be done about it. But, I would add quite a bit of expotential to the ailerons and the elevator. He's right, you may have way too much elevator throw, causing the model to try to, "Snap" with full elevator. Try adding the expotential to soften the input around neutral, and try to lower the endpoints or servo travel.

Bill, AMA 4720

MinnFlyer

My Feedback: (4)

Is the plane laterally balanced?

If one side is heavier, that aileron will always be lifting the wing to overcome gravity. Once you get to inverted, that aileron is helping gravity to drop that wing

aussiesteve

Maybe I can add some further info

He's a Mode 1 Flyer (elevator & rudder on the Left Stick) - One of only 3 that I've encountered here in Texas (When he came to visit me early this year).

The Elevator system on this model (Black Horse Super Air with an MDS 48 & 11/5 Prop) is from a single servo but with separate push rods (wire enclosed in a tube) to each elevator half (& a connecting block joining those two rods just prior to the servo). He's checked that both elevator halves are moving the same amount from neutral. I've also had him check the Lateral balance and to operate each channel at a time with the engine running on the ground to see if there is any interference to other control surfaces - all appears to be OK.

I haven't actually seen the model do this (He's in Australia - I'm in the US) so I suggested to him to post his query here to see what suggesstions he gets.

toothpick

thanks can you take over i must leave . and its a 10 x 6 prop

greenbaron

With the reduced elevator throws, try to move a bit forward the cg. This cured the same problem in my Yak.

EscapeFlyer

My Feedback: (1)

You are probably stalling out the wing, putting it past its "critical" incidence and creating too much disturbed air over the top of the airfoil. Check incedences, reduce throw, mix opposite rudder of the rotation in with elevator, play with you cg a little, and/or check both elevator halves to make sure they are in perfect alignment. Check these things one at a time. it could be as simple as Minnflyer's suggestion, I would check that first, but it sounds to me you are stalling the wing. At that point you have these forces working against you:

1-Engine torque; When the wing is stall there is no lift. The torque from your motor will spin your aircraft in the opposite direction you engine is throwing the prop. The only way to stop the effect of torque is to add opposite rudder.

2-Gravity; Your airplane is starting to fall out of the sky.

3-Forward inertia; Your aiplane is moving forward, but in a downward ark because of gravity.

Sometimes more throw will get you out of this situation, coupled with LOTS of LOTS of LOTS of POWERRR!!!

Agian, check lateral balance and elevator halves first.

My opinion.
Bipes

aussiesteve

Oh No - Don't tell him about lots of power - Now he'll try talking me into buying him a new engine (Something like an EVO 61)

Good Ole Toothpick likes speed & power!!

Seriously though - the stalling makes a lot of sense - that particular plane is very "Slippery" and If he doesn't keep his airspeed up it does tend to try and visit the ground as soon as possible. (It's the reason that he discovered how much he likes speed & power)

BillS

I have a Little Stik that exhibits a corkscrew tendency after the top of the loop is reached. The corkscrew starts at the top of the loop where speed is slowest because the vertical fin is less than perfectly aligned (front to back). Maybe your airplane is bent.

Bill

Super Splatter

Your plane needs triming, either a little weight on the correct wing tip or adding a little up alieron on one wing or adding a little up to ONE eleavator half.

Both eleavator halfs don't HAVE to be equal.

do loops both inside and out have a buddy write down what it's doing during the loops and think it out.

da Rock

Lateral balance is a good thing to check as has been mentioned.

Another thing that is often overlooked is how your two ailerons are versus each other. A somewhat finer detail of that is how are the ailerons in relationship to the wing.

I flew a guy's airplane for him today. Before doing it, I did all the usual checks. Pushed all the sticks and watched which way and how much the surfaces move. Did a balance check. Everything I did checked out. Flew the plane and it flew ok but took quite a bit of aileron trim. And something didn't seem right. Couldn't figure out what it was while flying. But planned to look at the aileron trim on landing and talk him into adjusting the trim into the airplane (he's a believer that computer radios were put on this earth to solve any connector problem).

On the ground I noticed that both ailerons had the "down flaps syndrome". Turns out that a couple of high speed stalls that I had thought were just the blustery wind could be explained by the ailerons. All the trim plus the down flaps had made one of the wings have a bunch of "wash in" so to speak.

When you ask an airplane that has some aileron trim to pitch, sometimes the down trimmed aileron wing will stall before the other. And sometimes the up trimmed aileron wing just won't give near as much lift as the other wing. Depends on the airplane and what you're asking it to do which symptom you see.

And what actually could be the cause when you've got an airplane that took a significant aileron trim setting....... whatever twist there is in the wings that caused you to have to counter that with trim. BTW, every airplane you've got with significant aileron trim on it.... check for warps and get 'em out if they're there.

It's always worth the look to stand directly behind any airplane and make sure the wing and ailerons are true.

toothpick

hi guys toothpick again

i have solved my problem ( about time too )

the problem was that it was far to nose heavy ( it needed 25 grams on the tail )
and it is now balanced well and flys like a dream again ( not like a golden dream aussiesteve )

aussiesteve

Better clarify what you mean there boy!

Do you mean like Dave W's "Golden dream" (which for the others was a motorised glider that got caught in a thermal and never came back) or Please explain what you mean.

Does it also do rising inverted flat spins now? - (Should do with the CofG where it is now).

toothpick

of course it'll do a rising flat spin as with my other high speed and performance models [8D]