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Author Topic: Flapper foam types?  (Read 197 times)
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mWang12324161
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8th grader from North Carolina interested in F1N.



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« on: July 22, 2019, 01:20:02 PM »

Hello!
I am trying to build a small-scale flapper glider with a wingspan less than 30 cm. I have heard of a few types of foams (Depron, pro formance, durobatics), but can anybody tell me which is the best for flapper gliders and how thin I should sand the foam to? Many thanks.
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Max Wang
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« Reply #1 on: July 23, 2019, 07:50:20 AM »

Durobatic if you can find it. 
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mWang12324161
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8th grader from North Carolina interested in F1N.



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« Reply #2 on: July 23, 2019, 08:22:45 AM »

Thanks!
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Max Wang
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« Reply #3 on: July 23, 2019, 10:02:56 AM »

The best foam I know of right now is Dollar Tree foam board. It has a paper backing both sides that must be removed. Either soaking in water or spraying with rubbing alcohol will loosen the paper (I can't remember which).

It's about 3/16" thick so it will require a lot of sanding. I would go for about .030" at the flap joint and taper to .020" at the trailing edge.

I would look for some plans for SO gliders that meet the rules. Here's the one I designed for the first year that gliders were flown. There was no minimum weight that year so everything on this plan could be scaled up in weight to meet whatever the rules say. With heavier wood you can leave off all of the diagonal carbon tow and possibly the spanwise tow as well.
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Re: Flapper foam types?
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spr
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« Reply #4 on: August 06, 2019, 05:00:38 AM »

Graupner's  Vector Board is an interesting new foam.  https://www.graupner.com/Accessories/Construction-Materials/Vector-Boards/

We have built several 300 mm indoor CLGs with 0,5 mm VB flaps and it seems to work well. No sanding neccessary, can be glued with standard cyano.  I guess JHaerospace has used it VB too in their glider kits.
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Olbill
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« Reply #5 on: August 06, 2019, 09:34:36 AM »

I haven't tried VB yet but it looks promising. Gluing with CA is a plus but I would probably go with UV glue b/c of the easy alignment.
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