Finalizing the tail surfaces installation

Once all the tail surfaces were in place, I made initial measurements with a smart level as well as a conventional level to know how far I was from the desired 2 degrees of incidence on the stab as well as zero washout as suggested by Doug Sowder's article on Pitts rigging. I was quite happy to find that without any tension on the tail wires, I was very close to the target incidence, with a little washout on both sides.

I used a tool that my friend Paul Goyette and I made for tensioning the wires. It is similar to the one that Steen sells, but made out of nylon and with a cylindrical shape rather than cubical. I think this home made tool is even less prone to damaging the wires than aluminium and would also cause less damage should I mistakenly drop it on fabric. I have two of them, one for the tail and one for the wings.

I slowly increased the tension by adding 1/2 turn on all wires, measuring angles and repeating until getting in the middle of the target range of 250 to 325 lbf tension. As I approached the final tension I realized I was inducing anhedral to the stab by doing 1/2 turns everywhere at each iteration. This is probably due to the top wires being longer and therefore stretching more that the bottom wires. When I realized that, I did one round of tensioning the top wires only, which brought me back to zero dihedral.

I used the Holloway Engineering tool along with an electronic torque wrench to measure the tension. 

Thanks to my girlfriend Isabelle who helped during the final stage of the tail installation!

Rudder

Tonight my goal was to install the rudder. First, I connected both elevator surfaces together. It was much easier to do this without the rudder surface in the way. I connected the aft elevator pushrod at the same time.

The bottom bolt was not reacheable with my torque wrench so I counted the number of turns on the bolt above when properly torqued, then applied the same number of turns on the bottom one.

Once the three bolts torqued properly and sealed, I went up in a ladder to reach the rudder surface on a shelf. Removed dust and patched a few scratches with small doilies cut out of polyurethane tape. In a similar way than for the elevator gap seals, I lubricated the rudder seals and glued the one above the top hinge to the fin. Next step was to install the rudder surface by bolting the two hinges on the fin using new hardware. While torquing, It was a little tricky to make sure the tail wire attachment horns were on the proper orientation. Here's the result with the tail wires fitted, but not torqued:

Next step will be the tail rigging!