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Electric System Lessons Learned
What I Would Do Different

I learned many electric system lessons as I installed the various systems in my aircraft.  Many of these ended up as notes on how I would do things differently if I were starting again.  Perhaps these will give you some ideas for better ways to build your airplane.

Wire up the tail before riveting the turtledeck

I didn’t have the luxury of waiting on the turtledeck until after I had run the electrics.  I was close to moving to Louisiana and had a half-built fuselage.  I needed to finish the turtledeck and the canopy to feel safe hauling it down the road.  Most builders will probably not face this problem. 

You can still accomplish a lot of building with the turtledeck only clecoed on.  The ability to remove the turtledeck will save you a lot of time and the pain of crawling into the back of the tail.  With the turtledeck removed you can easily rig the entire elevator pushrod, bellcrank system.  You can also reach over the side and drill the holes, run and clamp the conduit, and build and install any mechanical fixtures.

If I were able, I would have done all of the following before riveting on the turtledeck:

  • Built and installed the longer F-818C-L and R needed to hold the autopilot servo.
  • Drilled and primed all the electrical holes
  • Installed the outside air temperature (OAT) probe
  • Built and drilled the bracket for the Dynon remote compass, but not installed it (I think it would get in the way of crawling to the back to rivet, so would save it for later)
  • Run and clamped the conduit
  • Pulled the wires for the tail lights, elevator trim, OAT probe, and remote compass
  • Soldered the d-sub for the remote compass
  • Drilled and installed the static ports

Then after the turtledeck was riveted in place, I would finish:

  • Installing the pitch servo on the F-818Cs as I installed the F-635 elevator bellcrank assembly
  • Installing and connecting the remote compass
  • Installing and connecting the static lines
Wiring panel

Wire routing on back side of panelI am happy with my wiring, it all works!  But I think if I was to do it again, I would make a change to make removing the main panel easier.  At the top of the left gear box, I would install a plug panel with several d-sub connectors like in the picture.  The panel would have socket savers mounted to it, providing male on Connectors for d-sub panelone side of the panel, and female on the other.  Then all of the wire runs to the airplane would start there with a male fitting and go aft.  The wiring for the panel would start there with a female fitting and go to the back of the instruments.  I would run all the wires from the instruments into the center of the panel, then run the one large bundle to the left, then back to the d-sub panel.

I know this would add a little weight, but the ease of maintenance provided would outweigh the penalty. It will also make running the wires easier.  Measuring the length of the wire will be easier too because you will know exactly where to start measuring from at the panel end.

A quick look on the web found everything I would need:  socket savers to go through the panel, male and female connectors and their cases for the end of the wire bundles, nuts and screws.  I even found a help document that has the size to cut the holes in the panel.   I could connect up my entire panel for about $120.  In fact, I think the next time my panel has to come off, I will do just that.

Use multiple-wire bundles

I ran individual strands of wire for everything.  Next time I would use multiple-wire bundles, like Vans ES MSTS-WIRE.  It is the six-wire bundle needed to connect the trim servos.  The autopilot, and possibly the intercom, could also be wired with multi-wire bundles.

Although this may increase the parts cost a little bit, it will be a lot easier to install, and will weigh less.  You just need good measurements before you order to ensure you get what you need, and not a lot extra.

Permanent Labeling

One of the biggest electric system lessons I learned was in wire labeling. I labeled my wires with masking tape while I was installing them, and removed the tape as I crimped and fastened each wire.  BIG MISTAKE!  Now I have a bunch of white wires that look alike. 

I would suggest permanently marking both ends of every wire.  If you use multiple-wire bundles with colored wires, you can label just the bundle, then list the colors on your electric diagram.

The technique I like the best is the use of different colored shrinkwrap.  A single piece of one color can be put on each end of a wire, or you can mix colors.  For example, with just three colors of shrinkwrap, you can mark a 13 wire bundle like this:

Wire Label Diagram

Mark the wires on your schematic to match the shrinkwrap, and tracing electric wires later will be a lot easier.

Mounting the Radio Trays

You can see the green angle aluminum that I added to the top of the trays, thinking it would be easy to get to. I’ll move it to the bottom of the stack next time I pull it.I mounted the back of the trays to the F-802NPP L.G. Box Upper Brace with a screw.  I thought I had located it where it would be easy to install and remove, but it was harder than I thought.   I initially thought I would be able to easily reach the top of the radios, but that isn’t the case.  I have to remove my GPS and its mount to get to the screw for the radios.  Current radio tray setupOtherwise, with a lot of difficulty, I can reach through the radio trays to get to the screw.

The next time I remove the instrument panel, I will change the setup.  I will remove the small piece of angle aluminum I riveted to the top of the radio trays, and will rivet it to the bottom of the trays.  Future radio tray setupThen I will screw or rivet a straight piece of aluminum to the back of the F-802N that matches up to the angle.  Then I can screw the two together from below the radio trays without effort.

Landing/Taxi Lights

If I was starting a new project, I would check out the new Landing/Taxi/Wingtip combo lights.

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