Horizontal Stab Angle of Incidence Measurements

[MarkChristopher]

So I am ready to drill the final four holes to secure the horizontal stabilizer angle of incidence and I'm finding a disagreement between the right and left tooling holes. If I get the right side aligned front/back then the left side front hole is 2mm higher than the back hole. Of course if I align the left side, the right side is off 2mm. I have confirmed that the fuse is level and the horizontal stab is level with the fuse but the mis-match concerns me. I can split the difference and make each side off 1mm but before I drill, I want to know if others have had this issue?

As background: I am using a straight rod inserted in the two aft holes and another rod in the two front holes then I measure using digital calipers from the top surface of the rod to the deck on the fuselage. I have confirmed the spacers are in place and I am measuring as close to the holes as possible so as to not induce a bend in the rod.

Thanks!

 

[jpharrell]

Ignore the two front holes

I had a similar problem when I aligned my horizontal stabilizer. I called Vans and spoke to Ken. He said to only worry about the tooling holes between the forward and rear spars and ignore the tooling holes in the nose ribs. He said the main ribs are what set the angle of incidence of the horizontal stabilizer. I hope that helps.

John

 

[MarkChristopher]

Much Better

Thanks John. That did the trick. All the measurements were within about 0.5mm both front/back and right/left so I drilled away...