I had to retorque the AN173 bolts to the higher value and found out that the holes were not nicely aligned.
When I assembled the right spar I used a torque value of 29 inch/lbs. But later I found out that this should be 37 inch/lbs, that’s what I used for on the left spar.
So I had to disassemble the doublers again and clean the bolts with thinner to remove the red torque seal.
When assembling the doublers back I noted that the holes were not perpendicular:
I first thought that the holes were not drilled straight by TAF but after contacting TAF and measuring the location of the holes it all looked good.
TAF gave me the advise to insert the bolts from the tip side going to the root of the wing; this worked well and all holes are aligned now.
Some primer was removed while fixing this issue so I had to touch those spots with a bit of epoxy primer.
All holes aligned now:
Final result after torquing the AN173 to 37 inch/lbs:
All issues with the main spars are resolved now.
Upcoming 2 weeks I’ll travel to the USA, to meet Sling 4 builder Craig and going to Oshkosh of course.