Stuka Stunt Main Forum · 5 of 5 known posts recovered
>No one has mentioned sheeted foam tails here, most of what we fly all have sheeted foam stabs and elevators. They are extremely stiff, true, and as light as anything out there.
So how do you make sure they get this way? Should they be reinforced with carbon fiber?
The Foam Stab is made in two pieces, then glued together in the middle. We then make a vertical spar and insert it into a channel cut into the underside of the stab.
In a separate assembly, make a spar as follows:
Take two pieces of med hard 1/8" balsa that are 8" long and the width of the stab thickness just in front of the TE cap, less the top sheeting. If you have a 1/2" Stab, then the parts would be 1/8" thick, 8" long, and 1/2" minus 1/16", or 7/16" wide. Laminate the two peices of 1/8" balsa with Unidirectional Carbon fiber tape sandwiched in the center.
Back to the stab:
On the underside of the stab, mark the location of the 1/4x8" spar just in front of the TE cap. Cut through the sheeting and clean out the channel, down to the top sheeting and the TE cap. Glue the laminated spar in place & block sand flush.
When you cover the stab, overlap the covering material over the center section as you would a wing center. We use Carbon Veil, and double cover the center section.
We used to just use fiberglass cloth over the center, but the vertical spar adds more stiffness an is easier to do.
The result is a very stiff and lightweight stab. It also looks better than a sheeted balsa stab when it is all shinny, for it will not have that sag between ribs.
Curt
I get mine from Randy Smith. Sheeted, sanded, stabs and elevators.
Curt