The lower wing main panels have been assembled to the center section, the 1/16″ balsa sheet skin has been added, and the ailerons have been built in place. Now it’s time to do all the final shaping and sanding.
This is the left wingtip prior to any trimming or sanding. The tip of the leading edge (at left) is designed to be trimmed back to reproduce the curve of the full scale wing, and a filler block of balsa has been added inside the corner joint as a reinforcement. The two-piece sheet trailing edge has been rough-cut to shape. At this point both the leading edge and the tip laminate are still squared-off stock.
I have trimmed the wingtip structure to the correct shape as viewed from above, using the outline provided on the plan as a guide, but none of the edges have yet been shaped.
This is the top of the center section with all the 1/16" balsa sheet in place, but with no final shaping done.
This is the right aileron, built in place as part of the overall wing structure. The square strip sticking up above the surface is a 1/8" x 3/16" filler piece installed to bring the top of the rear spar up even with the tops of the ribs...it'll be sanded flush later.
As with the upper wing, I am using a block plane to rough-shape the square leading edge stock prior to finish shaping with a sanding block. The block plane is a good way to remove large amounts of material quickly IF you know how to use it.
I used a long, straight sanding block with 120 grade paper to form the leading edge to its final curvature and blend it smoothly into the ribs.
The same sanding block cuts all the lower surfaces of the ribs even with the spars. This spar is spruce and the ribs are balsa...snding parts of varying hardness demands careful attention and precise control. TAKE YOUR TIME...that's the only way to get a proper feel for what you are working on and get it right.
This is the aileron as initially built in-place...the angled strip will become the aileron leading edge and the strip in front of it will be the wing/aileron well trailing edge. The job here is to cut the top surfaces of all those edges, the trailing edge assembly, and the tops of all the ribs into a smooth surface.
I have finished sanding the upper wing surface to shape and fine sanded it to the degree of smoothness I want. The next step is to mark the aileron to be cut free. The pencil line defines the inboard end cut.
I am using a single edge razor blade to cut the outboard end of the aileron free from the rest of the wing structure. I like using an old fashioned razor blade for this job because the relatively long, flat blade surface makes a straight cut easier.
Here's the left aileron cut free of the rest of the wing structure.
I have rounded the leading edges and sanded the 1/16" center section sheet smooth with the rest of the wing structure.
This is the right wingtip with the leading edge and tip bow finish sanded.