Category Archives: Wiring

USB Port’s and Fuel Line

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Time: 4 Hours

I had two sets of wires for the two Dynon Skyview screens left deal with. The backup battery wires which already have a connector that will plug into to battery that I will buy at a later date. The other is the USB pigtail that you use to plug a flash drive into to update the Dynon software and instrument data. I could have just left the wires lay behind the instrument panel and access them through the back panel door.  I decided to add two panel mounted USB ports to make this a cleaner installation. I decided the best place for these would be next to the hobbs meter inside to forward baggage area. This would allow me to do the updates by just opening the baggage door and inserting the flash drive.

I curled the one foot-long cable to make it more manageable behind the panel.

I drilled the holes for the USB port and filed them to get a good fit using the flash drive as a guide.

I’m happy with how these turned out and it will make the updates real easy. The next thing I wanted to work on was to cut the fuel line on the outside of the fuselage. When I have the wings on an in-place I marked these lines to be cut when I have more room with the wings off. So I cut the lines put the nut and ferrule on and flared the ends. 

I put some red plugs in the ends to keep dust out. It’s been fun catching up on these little task and not messing with the fiberglass for a little while, man I hate sanding fiberglass! 

EMS Wiring

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Time: 8 Hours

I had a great day in the shop yesterday working on the EMS(Engine Monitoring System). This Dynon module allows you to electrically input information from many different items like oil pressure, fuel pressure, exhaust gas temps and other things that you want to see on your screen. The really cool thing about Dynon is that they allow you to make widgets on the screen in various configurations for the inputs that you connect. For example on my RV I will have my pitot tube heated which is controlled by a switch. However I would really like to know that the unit is getting the power and heating once I turn on the switch. The heat controller has a signal wire, that when the pitot is getting electricity and heating becomes active, that I will connect to one of the EMS inputs. Then I can create a widget on the screen so that when the pitot heat is off it will be black and when on it will be green so that I have a clear indication that it is working. So first thing to do was remove the shelf I made for the module and drill for the attach hardware, nutplates in the forward side and holes for screw/nut on the aft side since they will go through the cross member brace. 

For the rest of this installation my process was to determine which wires need to stay behind instrument panel in which wires needed to go to the firewall forward.  Once I had that information I determined the length of the harness so that I would have easy access to it should I ever need to work on it and clamped it to the baggage area panel.

With the harness connector secured I started the process of separating the wires that would go to the firewall forward and the ones that needed to stay behind the panel. 

As I found the ones that needed to stay behind instrument panel I went ahead and made those connections to the respective wires, like the pitot heat controller and other items, with a butt splice connector. 

The wires that were heading to the firewall forward I just hung over the firewall to organize them.

One thing that helped was taping the layout for a fuel injected four-cylinder Lycoming set up to the rollbar and highlighting the completed wires so that I knew which ones had been completed.

Dynon builds these harnesses to meet many different configurations so I will end up with a bunch of wires that won’t be needed. So those wires I flipped to the opposite side to organize them. I could cut or remove them however I thing I will just bundle/secure them out of the way for future adds if needed. 

Once I had all the wires connected behind the panel I connected the harness to the module in ran the wires that needed to go to the firewall down through the gear tower and forward through the firewall penetration hole. I cleaned up the wires with zip ties and coiled up the unused wires and secured them as well (they look like a colorful doughnut). 


The second harness on this module has wires that run to the firewall forward for the EGT (exhaust gas temperature) and CHT (cylinder head temperature) readings. I split these out to run left and right, the #2 & #4 cylinders are on the left side of the aircraft and the #1 & #3 cylinders are on the right side of the aircraft.  

On the left side I wrapped the 4 wires in heat shrink to protect them before they exited the firewall.



Three of the wires from the EMS go to the left and right fuel level capacitors. I drilled holes in the left and right side of the fuselage and used a rubber grommet to protect the wires it will put a three place Molex connector on these similar to the other connections I have done. 

I made a measurement to see how much extra wire I would need for the fuel level wires and made the cut. For these wires I will have the majority of extra length on the fuel tank side vs the fuselage side since I don’t want to have the extra wire showing in the cockpit since this area will be somewhat exposed.  


So now the only wiring I have left in the left wing will be the OAT temp probe, if that’s where I end up installing it. 

Wing’s Off

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Time: 10 Hours 

This weekend was another big milestone – I removed the wings! These won’t go back on until the paint is done. To prep for this task I had just a few items to take care of. The first was to drill all the holes that hold the wing/fuselage flashing on to a #19 for the eventual screws that will go there. Then I removed the flaps and ailerons to make the wings a little lighter for lifting. 


Then with a couple of hits to the temporary bolts that were holding the wing spar along with Glenn moving the tip of the wing up and down to take pressure off the bolts they slid right out. We then lifted them off the fuselage and put them back in their cradle for the remainder of work needed on them. 

Wow that was fun and I have so much more room to work now! One of the avionics I will have in my instrument panel is the Garmin GTN-625. This is a certified GPS navigation source and is the little brother to the 650. The only difference is that it doesn’t have the COM/NAV portion like the 650. All I wanted was the GPS enroute and approach capabilities. I have two Dynon radios and I will never do an ILS or VOR approach in this plane since RVAV/GPS approaches are all over the place.  Plus I didn’t want to put any mor antanaes on the plane. I won’t buy this unit until I’m all done but I did want to wire it now. There are three things that I needed for this. First is the tray that the unit will actually slide into and supports the unit. The second is the backplate which houses all the connections and the third is the connector kit that allows you to run wires to the backplate. I got these from JA Air in KARR where I fly out of. They had the tray but had to order the rest for me.


 So I moved on to attaching the tray to the instrument panel. It will be connected with four screws that will go into the brackets that SteinAir gave me when they cut the panel. I drill them for four #6 nutplates for the screws to go into. 

I squeezed a few rivets and the nutplates were done. 

I test fit the tray to make sure all was well and it looked great. 


Now that the panel was all done I was able to paint it for its final install. When the paint was dry I screwed in the Garmin tray and put them both back in the RV. 


I then decided to do a little wiring one was to remove the ARINC harness that I had originally built and run from the module up to the panel area. The reason is that SteinAir recommended sheilded wire which I didn’t use. 

So I rebuilt it with the correct wires, 22g two conductor wires. One for the TX set of wires, one for the RX set of wires and one for the serial line. While I was up messing with the wires behind the panel I decided to clean up the two Dynon screen harnesses. I have one for the 10″ and one for the 7″ screen. There were a few sets of wires that I wasn’t sure I would use or not so I just left it all hanging for the time being. They leave wires for contactor inputs if you so desire, all mine will be going through the VP-X so I won’t need them. The other set was for another serial input and those won’t be needed either. The last wire was for dimming capability from an outside dimmer control that I wasn’t going to use. So I gathered up all those wires and made a tight coil and zip tied them to just hang behind the screens after the install. I also zip tied the rest of the harness wires to clean them up leaving the GPS antanae wires out. I decided to terminate these wires in a connector so that when I finally decide where I will put the antanae I can just run the wires to the pane and plug it in. 


Now all that needs to be connected to these harnesses is the backup battery’s and the USB ports. It always seems that when I’m working on a task I see other items in that area that I want to work on. This was the same here as I was standing on the left side of the fuselage by the panel. When I installed the ELT remote head with tiny screws and nuts a while ago I didn’t think that I would ever have to remove that this after the RV was finished, but I found out that those part has a battery in it (I thought the one in the speaker housing was it).  The possibility of getting those little nuts in place in the blind would be impossible. So as I sat there looking at he back of the panel I had an idea. These 4-40 screws are small and don’t need to be very tight. I decided to grab some 1/8″ thick bar and cut two small peices, one for the left side of the ELT opening and one for the right. I drilled and tapped them using the ELT holes and used some of my T-88 structural adhesive to bond them to the back of the panel side peice. Now to remove the ELT remote I will just have to unscrew the screws from the front and not worry about nuts on the back. 

I was still in the mood for wiring, and not sanding fiberglass, so another task that I had been putting off was the roll trim motor wiring and install I will have pitch trim which is in the left elevator and roll trim which is in the floor just by my left hip as I sit down. There are five small 26g wires for each of the trim servos. Two are for the movement wither in or out based on which wire is getting power. The other three are for the trim indication, mine will be a widget on the Dynon screen that gets produced by the EMS(Engine Monitoring System) which has a bunch of blank inputs that you can use for items like this. To connect these tiny wires as they get to the servos I’m using RC aircraft/car micro connectors that Glenn used on his. The current that these carry is really low so these connectors work great. The down side is that they just have little prongs that stick out that you have to solder the wires on to. This meant that I would have to solder inside the fuselage bent over the edge. Glenn’s soldering clamps worked well for this. First up was to cut and drill the push tube based of the dimensions in the plans. This rod has two large cotter pins that act as points for springs attach to. Then the springs attach to the bottom of the control column tube. This rod slides into a bushing on one end and connects to the servo on the other with a pin. Then the rod moves left and right as needed but the springs allow the pilot to override the trim or just to use the controls when the trim isn’t working. 

I then test fit it all in place to make sure the movement was not binding. 

Then it was off to getting the connectors soldered. I made sure to put on shrink tube for the whole wire run, the shrink tube label and the small shrink tube to cover the individual soldered wires. 

I made sure to line the wires up on the servo so they matched the wire run and soldered them. 

With the wires all soldered I made the connection from the rod to the servo. 

More Fiberglass Work

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Time: 8 Hours

I have been slowly working on all for the fiberglass parts on the wing tips and VS/HS. The forward peices just ahead of the elevators and rudder are proving to be a pain to fill. Getting into the areas between the flanges is a littl tough. I’m using a larg popsicle stick with sandpaper glued to it to get into these spaces. These areas will probably take a couple of try’s to get just right. Man do I hate sanding fiberglass! On a side note I did get my AeroLED taillight from Aircraft Spruce this week. I was planning on using a watertight connector for this light since it will be in the bottom of the rudder and will be exposed to water from time to time. The problem was that the area in the aft end of the rudder bottom fiberglass gets pretty tight before the flair for the light. The issue with that is this peice will be riveted on and I will have to slide the cable in from the front and make it back to the hole. With a large connector it was impossibe. So I just used a small 5 place Molex connector that is easy to slide into place. 


I will figure a way to waterproof it after the connection between the light and harness is made. Maybe a long peice of shrink tube that covers the connector will do the job. While I was letting some epoxy cure for the next day I moved on to a little task on the flaps electrical connection. There is a side panel on the left side of the passenger seat that will cover up the flap motor. This creates a space behind it that I was able to install a two place terminal block to allow easy connection of the flap wires. This block will be screwed down to the floor that will eventually be permently riveted. I located the perfect spot and drilled for two #8 screws and riveted a couple of nutplates for them. 


I removed the terminal block and crimped the terminals on the two wires for the flap motor and the two wires from the VP-X.  Then I connected them for continued use of the flaps without the floor. 

I finished up a few fiberglass filling jobs as well. 


One fill job is on the bottom of the rudder where the fiberglass cap goes around the rudder cable attach horns. 

I have a lot of filling and sanding to go but I’m just going at it one step at a time. A few more standings on the wing tips and I’ll be able to call them done and be able to remove the wings. 

Flap Sensor

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Time: 1 Hour

I did some organizing and shop cleanup yesterday and did a little work on the flap position sensor that I had worked on a while ago. My main goal was to clean up the bracket I made and to finalize the wire connections. I decided to use d-sub pins, male on the sensor side and female on the wire run side, to make the connections based on recommendations on the vansairforce.com forums. These are small and light and work well with the very small 26awg wire. To hold them together I used small shrink tube which worked well. I also ran the wire aft and down following the smoke system pressure line. 

I like how clean this looks and will be easy to cut the heat shrink off over the d-sub pins to do maintainance or remove. I also put a nutplate in place for the screw that holds the sensor bracket to the bulkhead rather than a screw and nut. That’s because I forgot that this area will be covered by the baggage floor pan and will make it inaccessible.