Brief Description: Preparing ribs and drilling horizontal stabilizer
I notched the aft end of both left and right HS-404 ribs to fit around the HS-714 and HS-710 reinforcement bars I just finished. After laying out the cuts, I used the band saw to remove the outside flanges as specified in the HS-404 trim detail. I cleaned up the cuts with a file and 400 grit sandpaper. My next job was to straighten and flute all the ribs and bulkheads except HS-404 and HS-405. I would have to do these later when I knew where the holes would be drilled for the skin. I first bent the flanges so they were exactly 90 degrees to the rib face. I then used the fluting pliers to straighten each piece. I had to go back and forth until each piece was just right. I marked all the ribs with a single punch mark for left and two punch marks for right. I next had to drill four holes through the ends of HS-404 and HS-405 where they attach to the forward spar HS-702. I decided to cleco the skeleton together and then cleco the left and right skins HS-601PP to the skelton. Then I could just lay the HS-404 and HS-405 ribs in place with cleco clamps and mark the hole locations. With the ribs in place and marked, I used a 12" #40 drill to drill all eight holes. The long drill made it easy because I could flex the drill bit for perfect alignment as access was tight. I removed the 2 HS-404 and 2 HS-405 ribs and proceeded to straighten, flute and debur them. I clecoed the ribs back into place. I enlarged the HS-708 to HS-603PP holes to #21. I was now ready to match and drill all the holes attaching the skin to the skeleton. I used a #30 ream where the holes were already punched and a #30 drill bit for the remaining holes followed by the ream. I removed the skins and drilled the remaining #40 holes through the HS-714 and HS-710 reinforcement bars. Tired and time to call it a day.
