Brief Description: Fitting Horizontal Stabilizer to Fuselage
Unclamped the HS and reverified the forward bolt hole locations per dog 27A. I used a countersink cage and a short 1/4-28 threaded #40 bit to drill the left inboard hole to #40 and found that its location in the underlying g F-710B angle is too far aft. I re-clamped the HS in place and taking some more measurements, I determined that the forward edge of the HS-714 is about 5/32” further aft than the forward edge of the HS-710B angle rather than the 1/32 implied by Detail B on Drawing 27A. The hole in its original position would have caused the washer to interfere with the radius of the F-710B angle (Photo 1), so I relocated it 1/16” further forward, as I did the other three hole locations prior to drilling. This should be far enough forward to alleviate the washer interference, and far enough aft to maintain 7/16” edge distance on the F-714 HS lowers attach angle.
After pilot drilling the other three pilot holes for the HS forward attach bolts, I re-clamped the HS in place and ensured that is was square to the fuselage centerline. I then back drilled the #40 holes through the F-798 shims and F-714 lower forward attach angle, clecoing as I went. (Photo 2)
I then remeasured the HS angle of incidence, this time using the 3/16” steel rods across the bottom of the forward and aft lightening holes in the HS-00005 main rib. This method calculates out to less than 0.1 degrees, a number I can live with.