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General control line discussion => Open Forum => Topic started by: Motorman on February 21, 2021, 09:05:44 PM


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Title: Stab Flex Question
Post by: Motorman on February 21, 2021, 09:05:44 PM
I've got a kit that has 1/4" punk balsa for the stab. I could go on a rant here about 1/4" stabs in 500-600 sq. in. kits but this is what it came with. Obviously will be too flexible by itself so I want to make it thicker and stiffer. I decided to laminate pieces of 1/32" medium hard sheet on top and bottom. Also going to put .75oz bias cut fiberglass on it with Zpoxy. Anyway, my question is, would it be stiffer if I cut out the stab and glue in warren truss ribs or just leave it solid?


Thanks,
Motorman 8)
Title: Re: Stab Flex Question
Post by: Ken Culbertson on February 21, 2021, 09:13:37 PM
I've got a kit that has 1/4" punk balsa for the stab. I could go on a rant here about 1/4" stabs in 500-600 sq. in. kits but this is what it came with. Obviously will be to flexible by itself so I want to make it thicker and stiffer. I decided to laminate pieces of 1/32" medium hard sheet on top and bottom. would it be stiffer if I cut out the stab and glue in warren truss ribs or just leave it solid? Also going to put .75oz bias cut fiberglass on it with Zpoxy.


Thanks,
Motorman 8)
Had that exact issue with my Twister kit.  Stab was really weak.  I cut a 1/4" slot from about 3" from each tip and about 1 1/2" back.  I inlaid a 1/4" arrow shaft. I sharpened the LE and sheeted up to 1" from the t/e with 1/32.  Sanded to a slight airfoil.  Stiff as a board.  Flex in a stab really sucks and an airfoiled stab on a twister really made it perform.

Ken

Ken
Title: Re: Stab Flex Question
Post by: MikeyPratt on February 22, 2021, 12:56:19 PM
MM,
A simple suggestion is to just add a piece of 3/16 X 1/4 spruce to the trailing edge of the wimpy stab.  Ive done that a few times it works great.  Strong and simple and not very heavy.

Later,
Mikey
Title: Re: Stab Flex Question
Post by: Dave_Trible on February 22, 2021, 01:59:22 PM
I think I'd just substitute a better piece of wood,  make it thicker or put on a layer or two of .02 carbon veil.