This was one of those frustrating sessions where I learned a lot, accomplished nothing of any real permanence...but didn't ruin anything. All part of building an experimental aircraft I guess.
I read the Hartzell installation manual prior to coming out to the hangar so I knew for certain that the propeller was clocked incorrectly—something I had suspected yesterday when it wouldn’t tighten down fully. My goal in attaching the prop was simply to make sure that I understood all of the interaction between the prop hub and the cowling, as this is going to be a very visible joint and the plans/builder’s manual are somewhat lacking in detail. Ok…there is a lot of detail; I just can’t make much sense of it.
Now that I fully (?) understood the assembly, it would be a quick matter to fabricate a 2 ¼” spacer (per the plans) and attach the spinner flange for the upper cowl fitting. If it only worked that way!
The first task was to remove the prop and store it safely back in the shipping box. Check. The next task was to make a plywood “hub” to attach the spinner flange to. Check. The final task was to attach the temporary hub to the engine and fit the cowl. This is where it started to get frustrating. In my haste to fabricate a hub, I totally neglected to notice that it would ultimately interfere with the cowl, but that’s exactly what happened. Back to the drawing board to figure out a workable solution.
In the end, I worked out a plan to use a piece of 2” PVC to act as the centering mechanism (it fits perfectly inside the engine/prop hub connection) in order to ensure that the spinner flange is perfectly centered on the engine. I would then use additional PVC spacers to keep the flange at the correct distance and evenly spaced around the assembly. In order to do this, I decided to head for the house and cut the PVC on a miter saw…much more accurate than my little band saw. Enough for one day.
