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Old Jul 31, 2003, 03:07 AM
Andries Michielen
Andries Michielen
n/a Posts
Re: [EFLT] v-tail deflection vs. aileron deflection

This message from "Andries Michielen" <> brought to you by EFLIGHT!

This is a good reason to use more up than down movement on your v-tail. But
it was only found out after flight testing, I think you should start with an
equal movement to both sides and try to find out how much up or down
elevator you need in turns.

The reason why ailerons use more up than down has to do with side effects.
As you probably know increasing lift also increases drag (induced drag).
What you do with ailerons is create more lift on one wing and less on the
other which causes the aircraft to bank. Problem with this picture is that
you increase lift on your outboard wing and also create more drag which
causes the aircraft to yaw to a direction opposite to the turn, the reason
why especially gliders (large wingspan) need a mix of aileron and rudder in
a turn (the rudder counters the side effects of aileron deflection). With a
small down deflection the increase of lift and thus drag on the outboard
wing is minimized while the decrease of drag on the inboard wing is
countered by a larger deflection. Larger models still need some rudder input
in an turn.

Andries Michielen.

>From: "The Tellurian" <>
>To: "" <>
>Subject: Re: [EFLT] v-tails
>Date: Wed, 30 Jul 2003 16:31:26 -0400
>This message from "The Tellurian" <> brought to
>you by EFLIGHT!
>On my scratch built E.G.O.R.E. electric glider I found that more down
>tended to make the glider lift it's tail in turns losing altitude in
>the process. Putting in more up than down helped by keeping the nose up
>and making my turns flatter. I didn't need to work the elevator so much
>in the turns. E.G.O.R.E. is RET only, spans 70" and is 28 oz AUW.
>On Wed, 30 Jul 2003 15:02:41 +0100, Roger wrote:
> >This message from "Roger" <> brought to you by

> >
> >I'm currently toying with/starting to build a home brewed v-tailed

> >
> >1] Is there any advantage in having more up than down as is the way with
> >ailerons?
> >(or more down than up even!)
> >
> >2] I hope to use a tubular fuz, and would much prefer to bring the

> >out through the tube, i.e. underneath the vee.
> >Every picture in every magazine I have has carefully got this all

> >bit out of focus, or otherwise hard to see.
> >One case where a good drawing of the linkage is worth a thousand

> >
> >Anyone?
> >
> >TIA :-)
> >
> >--
> > Roger (Cambridge UK)
> >...advice is free, you don't *have* to take it!
> >Archive:

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