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Kitfox Trim Tab

11 posts in this topic

Posted

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Posted


Nice! I would'a never thought of using a bicycle shifter.

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Posted

I like the idea of using a spring & cable, the install looks pretty clean. Is the tab fully adjustable or is the shifter a more "on or off" approach?

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Posted (edited)

I have electric trim on my Kitfox 4.  It really helps to slow the plane down on landing if I crank in a bunch of trim.   Problem is that the electric trim is pretty slow.  And then it's slow cycling back to neutral for takeoff.   This is what I did to solve that issue.  Takes just a second to pull up the bungee cord.   Now I just use the electric trim for cruise settings.  1/4" aluminum solid rod, flattened the ends, and riveted them to the joy stick.   JImChuk

 

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Edited by 1avidflyer

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Posted

One of the main reasons I modified the tail of the Mangy was to incorporate a trim tab.  Hindsight, I would have made it bigger...

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Posted

I suppose if I had made a bigger trim tab then the one I have, the electric trim would have needed to move the tab less for the same results.  That would make it operate faster.  The bungee I did is supper quick though, and I'll probably just use that for landing.   On another trim situation, I have to ride the right rudder pedal.  I ended up shortening the cable a 1/4" or so, that makes the pedal a bit higher.  I think subconsciously we want our feet even in cruise.  If that doesn't work, I'll use a stronger rudder spring on the right pedal.  Hate to put a trim tab if I can avoid it.  JImChuk

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Posted

Just an  update on this last post of mine.  I did make a different lever for tightening the bungee for the landing trim, and it works real good.  Posted pictures in another thread.  Ended up going with a rudder trim tab, and after a few adjustments, it's working fine.  JImChuk

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Posted


I haven't flown my plane yet but I'm betting trim tabs on all three axis would be a good thing!

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Posted

Plane should want to fly level on it's own if it's rigged right.  Twisting the wing a bit will lift a heavy wing.  Sometimes a small rudder trim is needed if it doesn't want to fly straight.  I ended up putting a small one on my Kitfox.  Elevator trim becomes more needed though, cause you have the elevator in a way different position for cruise flight verses landing configuration.  That is when an adjustable trim tab can help quite a bit.  On our Chief, the elevator is pretty heavy if you aren't trimmed out.  On my Kitfox, I tend to float a good bit further without landing trim, and in my Avid, I don't use elevator trim at all except for level cruise flight.  Here is what I ended up with for a trim lever for landing on the Kitfox.  It works real good, way faster then cycling the electric trim back and forth.  Now it just gets used for cruise flight.  JImChuk

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Posted

I thought I had corrected this a long time ago, but if anyone copies this design, make sure you put a stop to limit travel on top and bottom.  It will get your attention if it jambs against the seat truss because you pushed it to far.  

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Posted (edited)

On the topic of rudder trim tabs... None are ever needed,  Grab the top of the vertical fin and the tail post and put a little pressure on the leading edge to bend the fin to get it to fly straight.  This is the same thing that is done for super cubs etc.  A little tweak and you don't have goofy tabs hanging off the back of the rudder causing drag.

Edited by akflyer
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