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Left Tank Installed and Pitot Mast Fitting

June 18th, 2016

Left tank installed AFTER LEAK TEST PASSES!

Now that the left tank has passed the leak test, I decided to mount it to the wing in preparation for riveting the skins on. I was pleased to find it generally fit well with no interference issues with the leading edge section.

Hmm…

There was one spot that makes me a little pause, but I am not sure I could do much about it. I tried to massage the skin of the leading edge some and considered making a small splice piece or some way to capture the skin from the tank, but in the end, opted to let it go for now.

Marking pitot mast hole location on left bottom outer skin

At this stage, I was at a cross road. I need a helper or two to rivet the top skins on, but did not have access to any for the rest of the day. So I went back to doing tasks I could accomplish solo. One of those was mounting the SafeAir pitot mast to the underside of the left wing. I prepped the template and then worked to get it placed, marked, and cut out. I have chosen to place my pitot just outside the outboard inspection plate. while this does require some additional attention when routing pitot tubing past the aileron bell crank, I think it’s a better location overall. Will provide good access from the inspection hole if needed and the web of the rib will help in making the mount more ridged. I’ve heard good reports by other builders that more outboard has worked well for them.

Drilling and mounting pitot mast

Here you can see the SafeAir mast placed and installed. As you can see, it sits against the side of the rib nicely. Now I can fabricate a small angle that will then attach to the rib and the mast, providing some good support for the mast. This not only give the mast an additional attach point, but reduces the stresses on the skin. May not really be necessary, but seeing how flimsy the attachment of the pitot on my certified Beech Sundowner, I wanted something more.

Like a glove

This was after many attempts at fitting, but with a little patience and filing, it fits very well through the skin.

SafeAir mast looks good!

 

Pitot mast bracket to tie into a rib

As you can see here, I took some stiffener scrap (likely from the tanks or elevator/rudder and fabricated a simple bracket that I riveted to the mast base with platenuts where screws will then attach the mast to the adjacent rib. This configuration is pretty dang solid once cleco’d in place. I am debating on placing platenuts on the remaining holes, including the spar holes, to make the mast completely removable, or simply riveting it to the spar and skin and if needed, drill out the rivets if maintenance requires it. Guess we’ll see once we get to the bottom skins where I land.

Categories: Major Wing Sections
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