CHAPTER 66 – Flap Connection

I had already rigged the flaps to the wings long ago, but the inboard top skin edge needed to be trimmed to match the fuselage; the first photo shows that accomplished on the left wing.  Apparently, though, I had rushed on the right flap.  It butted the aileron with no clearance at all and required a replacement hinge to space it properly; you can see that the replacement uses the new primer in the second photo.  I had also fabricated the control horn in reverse and had to redo the angle components.  I was able to redrill the plate as you can see in the third picture.  An embarrassing mistake but at least easily fixed.  Having the flap off gives me an opportunity to show how the hinge pins are secured.  A screw passes through the loops into a nutplate on the flap brace.

I was a little afraid to penetrate the fuselage for the flap linkages, but I used a 12” .040 bit and eyeballed it through the bottom.  A length of wire showed that it was fairly accurate and so I enlarged the opening enough to get the linkage through and attached to the flap and then finished the linkage long (or short) enough so that the flap was fully up with the arm in the up position.  My DC power supply came in handy here, running the flap motor to the desired positions.  You can see in the sixth photo that I have marked full up on the side of the fuselage.

Next, I bolted the upper end of the link to the flap arm and slowly enlarged the opening to allow the linkage to move in the down direction.  Leaving the stud end unattached allowed me to move the linkage out of the way while I enlarged the opening and yet I could quickly check the fit by placing the stud into the flap.  I used the motor on power supply to move the flap arm and kept working until I reached the lower limit.  I then bolted the stud into the flap and ran the motor both ways to be sure there was adequate clearance.  Finally, I repeated the process with the other side.