SUPER CHEETAH Restoration
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May 31, 2009
, 12:44 AM
Ask me about VTPR
Joined Aug 2002
Fab'ed up a new vertical fin the old s'cool way. Made up a pair of 1/4" balsa symetrical airfoil sanding formers and lightly epoxied them on top and bottom of fin foam core. I made the core longer so it can be fit as needed later. Sand, sand, sand the styro until it got fully shaped down to the sanding forms. I used a 12" sanding block to maintain uniformity. Once happy with shape i cut loose the formers to make ready for skinning with 1/16" balsa skin.
Once skinned and trimmed, new 1/4" balsa cap and leading edge are epoxied on, final sanded and contoured ready for monokote. Remember those formers i cut loose? When you do yours keep them for next time you need to make another fin. Will save a lot of hassle. Be sure and file away a copy of the total fin shape you traced for next time. Maybe make a few extra for those knarly combat sessions!
Top former major airfoil thickness dim = 0.475".
Bottom = 0.650".
Add skins and you end up with 0.600" top, 0.775" bottom.
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Sanded to airfoil formers using 150 grit on a 12" sanding block.
Sharp trailing edge.
Leading edge block sanded for leading edge balsa.
Sanding formers removed.
Skins are made out of 1/16" balsa joined at the middle with white glue.
Skins ready for application with 3M Super 77.
Skins are taped at the trailing edge and 30 min epoxy filled prior to folding the book.
Setting up an hour or two.
The empanage mocked up. Total weight 2.5 oz.