Brief Description: Wing Sweep and Incidence Angle Setting
With both wings pinned to the fuselage, it was time to check the wing sweep and the incidence angle. First, I leveled the fuselage using my digital Smart Level. I placed the level on the fuselage spar and shimmed the fuselage support to get a zero reading. Next, I placed the level on the top longeron and had to lower the tail just slightly for a zero reading. I placed a cleco at each wing tip in an existing hole in the top skin just forward of the wing spar. I placed a center mark at the tail end of the fuselage. Using my 100' steel tape, I placed the end over the cleco and pulled the tape tight over the mark at the tail and made a note of 16' 11/16". I did the same for the right wing and the reading was 1/4" shorter. I pulled the right wing tip forward slightly and clamped both rear spars. This time the readings were identical. I strung a Mason's line on the floor directly below the wing leading edge. I elevated the line using a piece of railroad track on one end and an anvil on the other end. I adjusted the line height to 6" off the floor. I took my 4 plumb bob's and suspended them from the wing leading edge to just above the line I had strung earlier. With the outer plumb bobs lined up the two inner were 1/4" off representing forward sweep. I could not move the wing tips farther aft because an AN470 rivet head was preventing the aft wing spar from moving closer to the fuselage. I would need to remove each wing and trim the upper end of each aft spar 1/8" I removed the pins and my son Reino helped me remove each wing and place them on saw horses. I trimmed the wing aft spar ends with my die grinder, deburred and primed with self ectching primer. Tomorrow I will reinstall the wings and start over.
