Elevators Completed!

Well it took a little longer than expected (about 4 months and 95 hours), but I am pretty happy with the results. The elevators were a jump up in the number of parts, assembly complexity, and a number of firsts. For example, I had to work with Pro-Seal Tank Sealant to install foam ribs in the trailing edges. The Pro-seal has two parts, has to be weighed to the gram, hand mixed, and then applied in a short time-frame. It’s a thick, very sticky tar-like substance. I also had to install the trim motor and crimp the electrical connectors, so there was a lot of research ahead of time on technique and options. And a bunch of new tools related to doing electrical work on a plane. Very different from home electric work. Below illustrates the journey over these past 2 months since the last blog posting, starting with finishing the trim tab.

Once the trim tab was completed, both the left and right elevators get assembled. The process involved back-riveting 1/2 of the ribs to each skin, adding the rear spar, attaching the skins together via the ribs, inserting the front spar, and finally riveting everything together.

Anna getting ready to assist assembling the left spar. 1/2 of each rib has been back-riveted to the skins.
The left elevator assembled, but before inserting the front spar.

Before completing the assembly, I decided to sign and date the inside of the skins. Weird to think when/if another human eye will see them.

After adding the forward spar, it was time to mix the Pro-Seal, install the foam blocks, then place weights (boards in my case) on top of the skins to help ensure contact of the skins to the wedges. I left it for a week to ensure a good cure before removing the wood.

Right Elevators after the foam ribs are installed.
And the left elevator

The trailing edge then needed to be riveted together. It’s a wedge shape and counter-intuitive in that the thicker edge is at the outside of the trailing edge. Cleveland tool sells a special dimple die set that perfectly sets the rivets. It worked really well except I somehow messed up the last rivet (of course!) and when i went to remove the rivet, i messed up the whole even worse. I ended up using an “oops rivet” which has a thicker shaft, but same size head.

My shame.
My shame.
All in all, the trailing edges came out really nice and straight.

I then had to install pins onto the trim tab motor. I used d-sub pins on the trim tab motor and cut off the mini-molex connector on the wiring harness, also adding d-sub pins to it. I just connected the two using the pins and covering each with heat-shrink tubing, and one large heat-shrink tube over all of them.

The steel pin used to attach the trim tab to the left rear spar had to bent so it could be secured against the spar. This worked out well and the trim tab attached pretty easily. The first moving part!! I then had to install the trim motor, attach the connector to the trim tab, and properly run the wire harness around the horn.

Once the trim motor and wiring harness was installed in the left elevator, it was time to roll the leading edges of both. This is a challenging processes. I take a 1.25″ wooden dowel, tape it to the top skin of the leading edge using gorilla tape, then use pipe wrench to bend the whole assembly. Slowly and with a lot of downward pressure. Then repeat for the top skin. By oneself it’s pretty tough, but the results came out pretty good (8.5/10) and there wasn’t a lot of pressure needed to insert the rivets holding the skins together, which is also an objective.

Both leading edges are rolled (the thicker outside portion)

Finally, I had to make some cuts to lead weights and install them in the elevator rib tips. I used torque seal to ensure in the future anyone can tell if the bolts have turned. From the EAA videos they say to not have the torque seal cover the threads of the bolt.

Lead counter-weights installed.
Josephine hanging with me one afternoon.

So that was about it. Now onto the final major assembly of the empennage – the Aft Fuselage, which is the rear tailcone. I’ve ordered the wing kit also because it’s a 10 week lead time and hopefully i’ll be far along with the aft fuselage to transition into the wings without much delay. Likely a bit optimistic.

Obligatory time lapse of about 45 hours of work to complete the second half of the elevators.

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