Empennage Inspection Covers and Gap Seals

September 13, 2013

We previously installed some aluminum rings back on the fuselage sides to make openings for accessing the elevator and trim tab horns as well as a hole for the forward attachment of the horizontal stabilizer.  

Now, using some .025 aluminum, some covers were made and drilled and clecoed to the aluminum strips around the openings as sown here:
gapseals1

You might be asking what the blue tape strips are for.  That is a favorite trick that I use to accurately locate a hole to be drilled in an exact location, when I can't see the location because it is covered.  Let me explain, - There is a 1/2" wide rib flange along the inside edge of the horizontal stabilizer. I want the gap seap pieces to be screwed to that 1/2" rib flange.  Here's how to do it:

Using my planned 3"crew spacing, I laid a long piece of tape at 3" intervals.  Then I made a mark on each tape (3" spacing) centered on the rib flange.  Now using a metal ruled a I drew a stratight line as shown above and made a mark exactly 8" from the center of the rib flange.

Now we can cut and place the aluminum gap seal in place, pushing it up against the fuselage side.  Holding the gap seal in place, a ruler was laid on the line and a mark made 8" from the 8" mark made previously.
gapseals2
If I am careful when I measure, drilling on this mark will allow me to hit the center of the rib flange exactly.

Here is the top gap seal all drilled and clecoed in place:
gapseals3
Note that an extra length is left out front.

On the forward edge, the gap seal was cut to fit over the bolt. The extra length was then wrapped to fit tightly around the leading edge of the Horz. Stabilizer:
gapseals4

The bottom strap is made for the bottom in the same way,

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