Hangar 9 P-51 Mustang 1.50 ARF Assembly Manual page 21

Step 5
Drill three 1/16" holes at the locations marked in the
previous step. The holes only need to be 5/16" deep;
don't drill through the top of the flap.
Step 6
Install one of the #2 x 3/8" screws into a hole drilled,
then remove it. Place 2–3 drops of thin CA into the
hole to harden the wood. This will eliminate the
potential of the screw pulling out of the wood. Repeat
this for each of the three holes.
Section 6: Flap Linkages
Step 7
Attach the control horn using three #2 x 3/8" screws.
Step 8
Attach the flap control linkage to the flap control horn.
Note: The linkage will be adjusted in Section
18: Radio Installation.
Step 9
Repeat Steps 1 through 8 for the remaining flap
servo linkage.
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