<April 10, 2007>

Pitot Plumbing (Fittings)

After a little thought, I figured out how I am going to connect my pitot tube plumbing inside the wing. The issue was that the brass fitting which come with the SafeAir1 pitot static plumbing kit, are a little heavy, and I didn't want them rattling around inside the wing. I could have just used some fuel tubing to join the 3/16" aluminum pitot tubing to the 1/4" plastic pitot lines, but that would have been way to simple and easy for me, I really wanted something more complex. ;-) I decided to use the AN adapter fitting that came in the SafeAir1 kit as a bulkhead fitting (see pic below) through a wing rib. This will allow me an easy way to connect and disconnect everything, while keeping it secured inside the wing.

After I spent a little time messing with the pitot stuff, I prepped the left outboard bottom wing skin for riveting. I still had a few screw holes to dimple and I shot some self-etching primer on the rib lines. It probably isn't necessary (to prime), but it gives me helps me sleep at night. I then spend a few minutes and rigged myself a rope and pulley system to help me hold the skins back while riveting. It will be interesting to see how it works out.

Here's the plan. I fabricated two custom washers/spacers to secure the assembly through a rib. The AN fitting on the right will pass through the thick spacer and then through the thin rubber washer before passing through a hole in the rib. The brass fitting will attach on the other side of the rib, using a custom washer I made from scrap AL. The spacer and washer were necessary as the threads on the AN fitting are NPT threads, and the brass fitting was going snug the threads long before the assembly would have tightened itself to the rib (clear as mud?). This way I can tighten the brass fitting down securely, compressing the rubber washer in the process, resulting in a nice tight fit through the rib.