Sunday, September 16, 2007

AV - Chugger's Tail

Back in May I mentioned I was using Pete Bower's Fly Baby as the basis for Chugger's tail. At that time (ie, 16 May 2007) I uploaded the drawings for the rudder and vertical stabilizer box-spars, which use 1/8" plywood shear-webs and 3/8" square cap-strips (as opposed to the 1/2" square cap-strips used in the original design). Chugger's tail is smaller in both height and span but I've tried to retain the elegant curves Pete used.

To ensure the four shear-webs would be identical, after rough-cutting them 1/8" door-skins I tacked them together on their center-lines and sanded them to final size as a single 1/2" thick slab. Since door-skins have an inner and outer face, when stacking them I made sure the rough-sawn blanks were oriented with the inner faces against each other.

The horizontal stabilizers use a built-up C-section for both their spars and diagonals whereas the elevators use box spars. As you can see in the drawings the diagonals are of a different size than the spars and are best handled as a matched pair. The six shear-webs for the spars are identical in taper but the elevator shear-webs are shorter. I treated these as matched sets of three, cutting the elevator shear-webs to length after sanding the stack to the proper taper.