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Old Aug 02, 2003, 03:02 AM
Johan Beyers
Johan Beyers
n/a Posts
RE: [EFLT] v-tail deflection vs. aileron deflection

This message from "Johan Beyers" <> brought to you by EFLIGHT!

This got me thinking:

Would the least drag not be achieved by just lifting the inboard aileron,
getting both the bank and desired yaw with minimal control surface movement?
I realise that you might need some up elevator, but would this not be
preferable to using both ailerons?

I know that some computer radios should be able to do this.

BTW, since my flying skills are newbie/Gentle Lady class, there's no way I
can test this for myself.

Johan Beyers,
Stellenbosch, South Africa

-----Original Message-----
From: []On
Behalf Of Andries Michielen
Sent: 31 July 2003 07:22
Subject: 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.

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