[grover]

the dwgs don't indicate how to establish where the vert stab fwd spar should be, vertically. is there a method to employ that is better than just eyeballing and estimating?

 

[Mel]

Mount the main spar to the fuselage (lower end). Run a string through the hinge brackets. When the forward spar is in it proper place, the string will be centered in all the holes.

 

[FALC0NDRIVER]

Mel's right. We went a little overboard on ours (first timers) using an electronic level, and a string through the hinges. I had to file off a tad bit of skin on the lower leading edge of the VS to get the string to center and 90.0 degrees on the rear spar. Good luck clamping and drilling. I think we checked everything 2 dozen times before we finally picked up the drill.

 

[alpinelakespilot2000]

Just got done with this two days ago. Like you found for the -8, the manual for the RV-9 says nothing about forward spar placement, but does say to put a straight edge against the 3 rudder hinge brackets and shift the forward spar around until the brackets are aligned. At this point the forward spar is at its correct vertical position assuming you've fixed the rear spar already. (A string through the holes would work just as well to measure alignment but it would require another person and a creative position to see through all three hinge holes at once.)

I think this is probably one of those tasks we stress out about but probably don't need to that much. FWIW, my middle hinge shifted maybe 1/64-1/32" out of alignment in the forward spar drilling process and my rudder still swings so freely that I can blow on it and it moves. Good luck.

 

[Mel]

I don't have the full plans for either the -8 or -9, but the preview plans do tell how to do this under "installing the empennage."