SafeAir1 Pitot Mast

[Arie]

Good day guys
I have fitted my Safe Air1 Pitot mast with the Dynon pitot tube to the bottom of the left wing skin. Just outboard of the aileron bellcrank inspection panel. I followed the instructions from Safe Air for the installation and it came out looking great. I do however have a question regarding the rigidity of the mast where it is riveted to the skin at the back of the pitot mast. The front overlaps onto the spar which is great but at the back I can see some flexing of the skin if I apply a force to it . About 3/16 inch flexing. I think I am going to rivet a light weight stiffener to the skin between the two wing ribs ( like the stiffeners in the bottom of the fuel tank ) aft of the pitot mast mounting plate. This should make the aft side much more rigid. What do you guys think??. [IMG][/IMG]
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[vic syracuse]

That will work. So will a piece of angle aluminum riveted to the rib, skin and to the mast.

Vic

[aeroaddict]

I did not measure the flex before riveting, but after the simple install without any extra reinforcement the mast seems pretty rigid after riveting the mast and outboard skin in place. Recall that the pitot plumbing will also provide some strength after final pitot install.

[sahrens]

I also added a short piece of angle aluminum to the inboard rib, skin and the mast. Everything seems quite solid now.

[JRichichi]

The pix below show how I mounted my SafeAir1 Pitot Mast. I made a small channel (1.00" high X 0.375" wide X 0.025" thick) and a couple of shear clips (0.625" (rib) X 0.75" (channel) X 1.00" high X 0.025" thick) and used some AD-41-ABS blind rivets to hold them together. I made another angle (0.032" thick) to mount the mast to. All of these parts were 2024-T3. I decided to use AD-41-ABS blind rivets since access was pretty tight to try to buck a solid rivet. Although the AD-41-ABS rivets aren't as strong in shear as the AD rivets, the shear clip joint is still 2.25X stronger than the bending of the channel.

I used solid rivets to attach the mast to the skin/spar and mount. If I ever need to remove the mast I can easily drill out the solid rivets. Then I can just unscrew the 0.032" thick mast angle from the inside of the wing and slide the mast upward thru the airfoil shaped hole in the wing skin. You could probably use some #6 flat head screws also if you want. I don't see myself having to pull the mast often enough to warrant that.

You can see the grip lengths I used for the rivets in the last pic (-4 & -5).

This wasn't all that hard to make and install and it greatly increases the strength and stiffness of the pitot tube mast. It also only weighs about 1.05 ounces so you shouldn't get too much of a "heavy wing" because of it!

[cdeerinck]

Very nice work!

Thanks for this post. I just got a Dynon Pitot, and was looking for a mast. After seeing this, I got the Safe Air mast, and installed it yesterday.

One question for you, where did you get the instructions on how to connect the pitot and mast? Neither the Safe Air, nor the Dynon instructions specified any details.

[JRichichi]

I just looked on this site and on various builder websites on how they installed the pitot tube on the mast. I used my mill/drill since I've got one. You could use a drill press and probably get the same results. I just marked on the mast the "thick" parts of the pitot tube where you want to drill and tap for the #6 screws.

I used some tape to hold everything together while I drilled the first hole. I clecoed that hole and moved on to the next hole and so on. Make sure you don't go too deep and damage the tubes inside the pitot tube. When all the holes were drilled, I deburred and tapped the holes. I then countersunk the mast.

Unfortunately I get to do the drilling and tapping on the pitot tube again since I'm in line to get the new "ice free" pitot tube. It shouldn't be too bad. I'll just slide the new one inside the mast, mark it and then pull it back out to drill and tap the holes. Hopefully everything will line up.

[Arie]

Thank you JRichichi. That answer all my questions!
Regards
Arie

[JRichichi]

No problem. Glad to have helped. I've learned a lot on this forum. I guess it's time to put some back in!!

Jeff

[Sylvainsting]

Hello,

I am french and it is a little difficult to adapt me to the imperial measurement system. So, what is the drill size for tapping a #6 screw ? 40 ?

Thank you
Sylvain