Joshua's RV-9A Project

After assembling the left tank to the spar, I prepped & primed the left wing skins and J-stiffeners.  The primer goes on nicely and dries quickly in the warmer temperatures and light wind, making the priming less of a chore…but standing in the sun next to the bare aluminum skins is like a solar cooker!

Once the primer had a chance to cure, I assembled the skins to the skeleton, again checking and re-checking the plumb bobs for twist.  The wing is pretty much dead on…less than 1/32″ difference from inboard to outboard end.  Clecoed every other hole…ready to rivet!

An afternoon of progress!  Began by taking the left tank out of the leak test setup and stashing those pieces for the right tank test.  I primed the tank’s top & bottom inside rear skins–where it contacts the spar–as well as the outboard end where it overlaps the splice strip.  I don’t know if this is really necessary or not, but since it’s in contact with other pieces, and I was setting up to prime today anyway, I figured it wouldn’t hurt anything.

After the primer had set, dropped the tank onto the spar and bolted in place, which went easily enough.  Followed up by installing the tank-to-spar screws, and only messed up the heads on 8 or so…sigh.  I think I need to find some better screwdriver bits.  They’re not too bad, but they’re a bit screwed up in the forward direction.  Throughout the process of attaching the tank, I was measuring and re-measuring the plumb lines to check for wing twist, but it stayed right on the whole time.

Some folks have trouble with the fit between the leading edge and the fuel tank, but mine is close enough that I don’t think it’s worth fretting over; it’s out by a half-skin-thickness in a couple places, but not bothersome.  I think this may be caused in part by the flat nutplates riveted to the curved splice strip, pushing it out of the necessary curve profile.

Later, I went back and did a final torque of the tank-spar bolts, and marked each one with torque-seal.