The following instructions are common for each flap section and aileron:

1. Clean mating surfaces of trailing edges with solvent such as lacquer thinner.

2. Etch same surfaces with Alumaprep or similar aluminum acid-type etching compound.

3. After thoroughly dry, apply well-mixed two-part epoxy glue.

4. Clamp between two 1/2 x 1 cold rolled steel or aluminum bars (1/2" edges against trailing edges).

5. Hold straightedge on top surface of each end and sight for twist. Any twist can be removed without loosening clamps by applying a torque at one end while restraining the other.

6. After resin has thoroughly set, drill and countersink #41 holes in trailing edge close to bend line. Do not countersink fully as basic hole will be enlarged. A small fillet in the bend will hide any of the high heads when the surfaces are painted.

7. Install hinges by marking to mate with wing hinges. Use a gauge to get proper alignment with wing skin.

8. Install end ribs.

9. The aileron must be trimmed to fit between wing tip and actuating arm. Allow 1/16" counterbalance clearance at wing tip.

10. Fit No. 4 flap with 1/16" clearance between outboard end and alleron.

11. All other flap sections are fitted with 3/16" end clearances to allow for wing flexing.

12. Trim root end of No. 1 flap to line up with wing root.