While I was letting some last-minute primer cure before assembling the left flap, I fit the Safe Air pitot mast to left wing spar and bottom outboard skin.
I started by fitting the mast to the wing spar. If the joggle in the base plate was allowed to nest against the edge of the spar, the forward edge of the plate would interfere with the shop heads of the rivets in the leading edge. To alleviate this, I put an 0.025 shim between the mast plate and the rivet heads before marking the template for the rivets through the main spar.
After drilling the template spar holes through the bottom outboard main skin, I transferred it to the exterior, and clecoed and taped it in place. I then drilled a series of small holes through the skin just inside the outline for the streamlined mast. After removing the rough cutout, I used my die grinder and 1/4" burr to grind back to the line on the template. I then cleaned up the hole with a large radius needle file. After checking the fit of the mast in the hole, I match drilled the mast plate through the forward edge of the skin, and drilled and countersunk the holes attaching the aft corners of the mast plate to the skin.
Though not called for in the installation instructions, many builders add a reinforcement angle between the inboard edge of the mast plate and the adjacent main rib. I'm going to check further before committing to this mod.
Checking the fit of the mast to the main spar.
Rough cut out for the mast.
Final fit of the mast in the bottom outboard left wing ski
