Tail Wiring

May 8, 2020 – I ran the wiring from the tail forward towards the cabin.

I have the wire bundles for the taillight and for elevator trim. Trying to figure out the cleanest and safest route for the wires…

Here’s what I started with:

I didn’t like the lack of support going into the tailcone. So I drilled a hole in that upper bulkhead and placed a snap bushing there.

I realized I was going to need a path all the way up at least to the wing spar. I was also going to have to run coax from the transponder and ADSB antennas that way, and I couldn’t figure out how I was going to do that. My seat pans are riveted down, so I didn’t know if there was a way to run wires forward under those. The bulkheads are solid forward and aft. So I took a look at the drawings for those bulkheads.

Well, I realized that some holes were hiding from me. I already had holes and snap bushings in the bulkhead between the seat pans at the flap torque tube.

That was half of the problem…how do I get the wires past the elevator torque tube at the baggage bulkhead?

I looked again at the drawing for that bulkhead. Wait a minute…there can be holes there. I don’t really know why I never drilled them.

So okay…I have to drill two 5/8″ holes in there with limited access, without hitting the rivets or damaging any structure.

I carefully drilled two #40 holes, and then took them up to 1/2″ with a small unibit. How to get to 5/8″? A friend had welded a rod onto a large unibit. So I could chuck it into my 3/8 drill and get it down in there.

Here’s the result…

Deburring was almost as much fun as drilling these holes…. Just have to do some paint touch-up too.

And here’s the final result:

I installed a clamp on a bulkhead to hold the wires clear of the elevator pushrod:

I finished this by lunchtime that day, but with the crawling around back in the tailcone, I was ready to go home and go back to bed…

Time: 8:30

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