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Old Mar 11, 2004, 09:20 AM
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Aileron/elevator coupling

Does anyone know the effect of aileron/elevator coupling on roll characteristics?
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Old Mar 11, 2004, 09:45 AM
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Like this....
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Old Mar 11, 2004, 10:10 AM
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If you are coupling each elevonseperatel, it will negate the roll moment.

If you are always adding e.g. up on both to roll, it will barrel roll it.

Better to couple in some rudder I'd say.
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Old Mar 11, 2004, 10:21 AM
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That's what I was afraid of. I was trying to keep the number servos to just two and not have to run a rod across the inside of the fan duct.
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Old Mar 11, 2004, 10:49 AM
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I've done it on a V-tail. Rolls aren't axial at all, and I doubt they would be even if the tail was flat. There's some imbalance on the forces acting on the control surfaces from front to back that's not helping. It's still quite flyable, and elevator response is great.
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Old Mar 11, 2004, 10:49 AM
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Well thats easy, use the rears as tailerons.
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Old Mar 11, 2004, 11:02 AM
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Thanks guys!

Vintage1, does that mean you don't use the ailerons at all?
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Old Mar 12, 2004, 07:01 AM
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Yes.. look at a zagi..
..a
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Old Mar 12, 2004, 07:15 AM
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I read tailerons don't control rolls well. Is that true? I have a zagi fixx and it rolls terribly. Didn't know if that was due to the overall design. I was thinking about using tailerons on a F-16
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Old Mar 12, 2004, 07:21 AM
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To get axial rolling you want the roll moment roughly where the CG and the center of lateral resistance is. Ailerons do this well on a mid wing.

SHOULD work elevon wise on an F16 as well. However not sure how effective they would be - there's not a lot of span.

Mind you, go fast enough and it should be OK.

I'd be tempted to use 'all moving' .

My picojet rolls cleanly with elevon control.
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Old Mar 12, 2004, 07:28 AM
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Folks have converted those little styro F16 gliders to RC, and used the elevator controls only to effectively control the model. You just cut the entire horizontal suface off, and mount each one to a servo directly. You end up with a full flying or all moving surface - just like the real F16 - and it works well enough.
..a
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Old Mar 12, 2004, 07:42 AM
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Thanks!
I had planned to use full surface to begin with
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Old Mar 12, 2004, 08:11 AM
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Nice! Will it stay 'profile' or get its nose filled in?

I'd certainly try elevon mixing and two tail servos to try it out.

Before it gets more complex...

And I'd put in a little more up than down differental wise....
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Old Mar 12, 2004, 08:21 AM
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Thanks! It gonna stay profile.

Do you mean "a little more up" in the aileron or elevator function of the elevon.
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Old Mar 12, 2004, 08:28 AM
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yes.

I had an idea to do something like this for a starfighter - fake it up in sheet balsa with a small fan.

Love to hear how it all goes.

Aren't you up a bit late there?
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