Funbuild 5 Beechcraft D-18
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Dec 05, 2011
, 04:51 PM
United States, WI, Fond du Lac
Joined Sep 2008
After the top cut is made, lift off the top building board and glue down the top skin. I pre-form the DT foam skin into a curve by rolling it with a piece of plastic pipe on a couch cushion. The harder you push and the smaller the pipe, the tighter the curve. Apply glue to the ribs and place the skin on the ribs. I use white Gorilla Glue. If you apply just the minimum needed to attach the skin you can hot wire through it with no problems.
Replace the top board and weight it down to clamp the skin in place while the glue sets.
With the soft DT foam, pre-forming is needed. Otherwise, the weight needed to get the skin clamped to the ribs will dent the foam. (Not a problem with balsa skins.) The building board only applies clamping force to the ribs so the skin doesn't sag between ribs.
I used Dollar Tree foam and Iíll cover it with kraft paper and WBPU. Balsa also works great with this method and makes a really strong wing. The foam and paper will weight about 25% less than 1/16Ē balsa and a light glass cloth/epoxy finish. Iím also going to splice in a section of LE to handle the area between root and nacelle and that will be easier with foam so thatís what I used.
Once the glue is dry remove the top building board and trim off the excess skin at the root and tip. The excess at the LE and TE will be trimmed off when the cut is made for the bottom of the wing.
Add the templates for the bottom of the wing. Before replacing the top board apply several pieces of double-sided tape to the rib cut offs stuck to the top building board. Carefully replace the top building board using the spar slot cuts to make sure itís properly lined up. The idea is to temporarily attach the wing to the top board to hold it in place when the bottom is cut off.
Make the cut for the bottom surface.
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First cut made.
Glue and pre-formed skin applied.
Replace the top board and add weights to clamp the skin in place.
See how the rib blanks apply clamping pressure only where you need it.
Templates attached for second cut.
Second cut made.