Aileron construction is nearly identical to the wing construction...wood spars with nailed on aluminum ribs. The difference lies in the fact that the ribs "slide on" the spar. This means that the center ribs must be installed before the plywood reinforcement places are glued on.
The center reinforcement is not plywood, it is solid spruce with tapered ends. Photo 2 shows a scarf box used to make the tapered ends. The scarf box is made from a 2X4 base with plywood faces that have been band-sawed to the correct angle. The reinforcement plate is clamped into the scarf box and then a plane is used to trim the material.
Photo 3 shows the mixing of the resorcinol adhesive. Resorcinol is used because it was the adhesive used in the 40's to build up spars and is thus the "legal" adhesive today. It is applied with a paint brush (Photo 4). To prove the integrity of your glue joints make a couple of test blocks at the same time as the spar is glued. (Photo 5) Then clamp the spar reinforcements and the test blocks (Photo 6) and wait overnight for the glue to cure.
Now the spars can be varnished...except for the areas that will have plywood reinforcements. Use masking tape. (Photo 7) Remember, we'll assemble the ailerons in 6 steps: 1. glue on center reinforcement plate 2. varnish all except plywood reinforcement areas 3. install center ribs 4.glue on plywood reinforcement plates 5.install outer ribs 6. varnish again.
Photo 8 shows the plywood reinforcements being installed. Nails are used to hold the plywood plates while the glue sets (Photo 9)
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