<September 19, 2006>
Rough Installed Pitot Mast
Tonight I set out to install the pitot mast. Some months ago, I had purchased the SafeAir1 pitot mount, but for the past few days I had been having second thoughts about it. There was nothing wrong with it, but started thinking that the stainless steel pitot that Van's sells for around $25 was the way to go. It would be cheap, simple, effective, and light weight, but it wouldn't be heated (if that feature was important to me). I thought about this for a day or two, and decided in the end to go with the SafeAir1 mast. I did this for one reason, long-term flexibilty. This way, if I ever decide to install a heated pitot, I can. Besides, I already had the SafeAir1 Mast in hand.
Hmmm... something isn't right here. I drew a line along the center of the mast and held it inside the wing to see how close the masts flange would be to the rib. As you can see here, if I had lined up the center of the mast with hte rivet hole they suggest, it would have hit the rib. This isn't a big deal, I could have moved the mast outboard one complete rivet, but I figured they had good reason for instructing you to install it here, so I decided to just offset the mast by about a 3/16" outboard.
Update: Sometimes I ain't so smart. The instructions for the mast were written a while ago and apply to a RV-6. The spacing of the wing ribs on a -7 are a little different. If I had actually read the directions instead of just looking at the paper template, I probably would have figured that out. This really isn't a big deal at all, I just thought I would point out that I am an idiot sometimes. If I had to do this again, I probably would have mounted the mast an inch or two further outboard, but it really doesn't make any difference.
I drew some reference lines on the skin and taped the template into place. Looking at the paper template, you can see where the mounting plate of the mast will covering the first (forward) row of rivets holes in the spar. Again, two choices here, offset the mast aft about 1/4" or grind a 1/4" off the forward edge of the mounting plate. Again I decided to follow the directions (template) for placement, and elected to grind off a little bit of the masts mounting plate.
No turning back now! Using the template, I outlined the shape of the mast on the skin then drilled the skin using a unibit. After the unibit (step-drill), I used a grinder in my Dremel tool to get the hole closer to the line.
I smoothed the hole out with files, sandpaper and a Scotchbrite pad. When it was all said and done the mast fit fine. The hole was slightly larger (1/32") than it needed to be but that is fine. You won't be able to tell once the plane is painted.