The summer has past with almost no work done on the Tailwind - too many distractions have competed for my available time. However with the shorter days the scope for outdoor activities has reduced and it is time to make some progress. The fuselage has been wrapped in a large tarpaulin and parked in the drive so I can get on with skinning the wings. First job is one I have been putting off, joining the two sheets of mahogany ply that will form the top surface. If you google scarfing there are all sorts of mechanisms proposed ranging from simple sanding, through routing to sawing. The idea is to create a matching slope on each piece of wood so that the glue area is increased. Typically, the slope is of the order of 12:1, so in the case of the 3/32" plywood used for the wings the gluing area will be increased to 1-1/8". I elected to use my powered plane to cut the scraft angle. First a piece of angle aluminium was fastened to the plane to create the requisite 12:1 slope. Also, a piece of aluminium was screwed to the bench to create a straight edge for the plane to run along. Then, first on a piece of scrap material pushed tight against the straight edge, the plane was run along the width of the board using a cutting depth of 1/32".
Much to my surprise this worked perfectly cutting a neat line along the edge at the requisite angle. Two more passes of the plane cut the full depth of the joint.
The scrap material was then cut to form a run-on and run-off for cutting the actual material. The full sheet of ply was then positioned and the three passes made again - another success!!
This was repeated for the other full sheet of ply and two shorter pieces which together will cover the top surfaces of the wings and the wingtips.
