Brief Description: Drilling and bolting horiz stab
Today involved measuring a million times, then drilling and bolting on the horizontal stabilizer. It is attached at 4 points - 2 front angle brackets on the front spar (pic 1) and 2 rear bars that attach to the rear spar (pic 3). First step was to measure that the stab was square to the fuselage by measuring from the firewall to a rivet I chose on the ends (last rivet on the front spar before the end rib). After checking a bunch of times and making the little spacers that fit under the bracket feet, I drilled one hole, rechecked the square of the tail, then drilled the opposite side. After slipping in bolts, I drilled the other 2 holes (which I did first via a #30 pilot hole then enlarged to 3/16") in assembly. Next was to set the incidence (angle of the stab when viewed from the side) - a 11/32" drill bit was receommended by Van's lifting the rear spar (pic 2). I then doublechecked by measuring the distance from the tooling holes in the inboard ribs in front of both spars (see with ruler in pic 2, and hole visible in pic1 next to angle bracket) - they are supposed to be equal and were! The vertical attach bars were already predrilled undersized when fabricated a long time ago - I just backdrilled to size through the rear spar and bolted. Worked great!!
