Tuesday, February 26, 2013

Preparing Landing Light Ribs & Lens Backing Strips

The afternoon was spent preparing the landing light mounting ribs for both wings along with the lens backing strips. The landing light ribs require a doubler plate to give them some rigidity in the area where the light mounts. AN426AD3-4 flush rivets are used secure the doubler plates onto the landing light ribs. The doubler plates were machine countersunk prior to priming, so they were ready to rivet onto the landing light ribs.
                              Using the pneumatic squeezer to secure one of the doubler plates onto a landing light rib.
                         Front and back views of the landing light ribs after the doubler plates were riveted in place.

The plans would have the builder drill mounting holes into the Plexiglass lens along with trimming the lens at this point. However, from everything I’ve read, it should not be attempted if the Plexiglass is below 70 degrees. Guess I will need to wait until spring thaw to finish that aspect of the landing light install.

While the pneumatic squeezer was in use, decided to finish up the preparations for the lens backing strips used to secure each landing light’s lens onto the W1203L&R wing skins. The backing strips receive K1000-06 nut plates which require dimpling because the rivets used for mounting the nutplates are flush rivets. The reason for this is the backing strip compresses the Plexiglass lens onto the wing skin to keep it secure, therefore the backing strips need to be smooth so they won’t crack the lens. The backing strip rivet holes were dimpled prior to priming as were the nutplates … so once again it was easy to just rivet the previously prepared components together.
                                             Using a pneumatic squeezer to rivet a K1000-06 nutplate onto one
                                             of the lens backing strips with AN426AD3-3.5 rivets.
                                Completed lens backing strips for both landing lights … ready for final assembly.

The rivet holes in the W1203L skin for mounting landing light ribs have not been drilled yet. I wanted to see if it was possible to insure a really perfect fit for the landing light ribs between the top and bottom of the W1203L wing skin … so I experimented a little. I temporally mounted the landing light onto the landing light ribs and tried to position the assembly perfectly behind the leading edge. That idea turned out to be pure folly because it was almost impossible to hold the light assembly in position just to look at it, yet alone drill. Even if I had another pair of hands, I don’t think my small 90degree drill would have been usable in the cramped quarters. Guess I will have to use the template with blind faith and hope for the best.