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Jan 19, 2020, 05:02 PM
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Has anyone experimented with more than 2 steps?

I'm also currently considering a design that'd need the first step closer to the leading edge. Before I go in that direction, has anyone got any experience that should put me off that pursuit and stick strictly to 50% chord?
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Jan 19, 2020, 05:19 PM
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I've found this

And noticed the Kfm9 is effectively what I'm designing for.

Still, how dependent are kfm foils on the step position?
Last edited by zioruk; Jan 20, 2020 at 05:21 PM.
Jan 19, 2020, 07:36 PM
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Flow separation on a normal airfoil usually occurs at roughly 30%, that's where the KFM step should be placed.
You can add a second step at 55%. Each step should be (ideally) 33% high of the total airfoil thickness.

Steps at the undersite are a different story; ideally 1/3 of the airfoilheight and at 50% from the leading edge.
Jan 19, 2020, 08:25 PM
springer's Avatar
On the first page, second post, is a chart of current KFM variants.

They are up to kfm11!

A member username viking (plus a number, I think ) has played with enough steps to approximate a conventional airfoil.
Jan 21, 2020, 07:58 AM
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davereap's Avatar
Ive tried lots of variants... It just depends on your aims for the wing.. for multi steps The first step I usually set at about 25-30% chord and that is the thickest part of the wing, where the main spar would go.. additional steps are spread evenly over the remainder of the wing..
For the simpler wings follow the guide for positions.. and you wont go too far wrong..

step locations are not critical..the guides to %age locations are where they worked ..
Jan 21, 2020, 09:47 AM
springer's Avatar
Finally found it the username is Viking60! Looks like most of his fiscussionbof multiple step wings is in the two KFM sticky threads at top of forum first page. Well worth a read or some key word searches.

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