Avionics and Wiring

October 22, 2020 – I realized when I looked at my time log how long it’s been since I posted an update, so here goes…

Com Harness

I finished the connectors and put the harness in place. I’m trying my damnedest to not have a rats nest here. Once everything is clamped in place and tied back, it’ll be OK. This is what happens when a sheet metal guy handles wires.

I did the headset and mic jacks. I made some a long time ago, but I didn’t have wires for PTT in there, so I took mine out and used the new ones.

I also installed the antennas.

Tailcone Wiring

Well, I call it the tailcone because once I get in there, I may as well be all the way back there.

I assembled the harness for the autopilot pitch servo. Power, ground and a yellow wire for AP disconnect go up front. The rest go into the Skyview network.

Since I have limited space for wires to go up the tunnel between the seats, I bought a hub to put in the tailcone and I ran a 15-foot Skyview network cable to the front.

I made a bracket where the transponder attaches to the center beam in the fuselage.

Air Temperature Probe

I installed the OAT probe in the fuselage under the left horizontal stab. I ran the wires up through tiny grommets I had and they go straight to the ADHRS.

Panel

For a long time I had the “life-size” Dynon templates taped to the panel on my table and I was playing around with them trying to find the best locations. When I was ready to make a decision, I found out that those templates were about 1/4″ small. That made a big difference in what I was going to do. So I did some rearranging.

In the above pictures I have the two coms with the intercom panel above them. I wasn’t sure I liked that, so I redrew that stack with the intercom underneath. Much better.

I decided to do the cutting myself. Lots of filing…

It appears that except for the intercom panel, all the Dynon panel items have the same cutouts. Nice idea…

After those center items, I did the cutouts for the screens.

Here’s the panel in the airplane:

I still have to do the other small items in the panel, which I just ordered.

I’m just going on, routing wires and terminating them as needed. One wire at a time…

Time: 42:00

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Avionics and Wiring (again)

September 24, 2020 – Well, it’s been an interesting few weeks. After losing both of my parents and a covid-like illness (I was negative!) I’m back. We won’t talk about my flying! That’s another issue. But things are moving forward with this project.

I looked more into locating various items in the airplane. Because of proximity to antennas, I decided to put the ADSB-In box back there, as well as the transponder. Van’s sells brackets that are for an ELT or strobe power supply. I decided to get one each for the left and right, one for the ELT in the future, and one for the ADSB. Because the ADSB antenna is on the right side, that’s where I placed this bracket.

ADSB

Access to install this bracket was a pain. It attached between two stringers behind the baggage compartment. It fits fantastically, but it gets pop-riveted in place in the stringers. Note to self: install the lower rivets first, then the top ones.

Antennas

My darling wife came out to the hangar and helped me install the ADSB and transponder antennas.

I also ran the coax cables for the com antennas.

Com Harness

I think the biggest part of this project is going to be the com harness. This connects the two transceivers, the intercom, and the two radio control heads in the panel. Dynon does not sell a harness for the whole thing, but they do sell one for the intercom, which appears to be the heart of the machine. Because I have two coms instead of the one officially supported by Dynon, I found out I had to add two pins to the intercom harness. Took me two tries because I wasn’t paying attention to what I was doing, but I got that done.

After much head-scratching and consultation with experts on the airport, I called Stein and found out they would sell me a drawing of the entire com system provisioned for my setup.

Armed with this information, I laid out my version of a harness board on my work table, with close approximations of distance and relative positions of each component.

I started with the connectors for the transceivers.

I haven’t closed them up because I need to install the power wires from the VPX.

In order to get distance correct, I wanted to locate the harness in the airplane where the connectors would be. I made up a template out of posterboard with the locations of the three panel items. I’m sure there’s am easier way to do this…

I think before I get too much farther along, I’ll consider starting to get the panel ready to cut.

Time: 27:00

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Avionics and Wiring

August 29, 2020 – The wiring continues…

Still figuring out how the wires will be routed from elsewhere in the airplane to behind the panel. Looks like I’ll use the center tunnel forward past the fuel pump to the firewall, then up the right side and back to the sub-panel. I drilled a couple of holes for clamps on the firewall angle on the right, then started running wires that way…

I installed the base plate for the transponder on the beam that runs aft from the baggage compartment bulkhead, then ran the harness wires forward through the tunnel.

I then populated the two main power connectors for the VPX.

I knew that I had to have three power outputs for each com system, that would come off the one power source. So I used solder sleeves to achieve this.

I moved on to the pitch servo for the autopilot. I terminated the wires from the servo into a DB9 connector. I made both sides of that connection. Then I installed the servo onto the bracket.

I then tried my hand at terminating a coax cable. I made the cable for the transponder. YouTube is my friend.

Time: 13:00

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Avionics and Wiring

August 10, 2020 – Just slogging through the avionics.

Engine CHT and EGT

I knocked out the EGT and CHT wiring so I could have some visual progress. Dynon provides spade terminals to match the harness wires which are already terminated. I allowed for service loops with each wire, and I tried to offset each one to reduce the bundle size when it’s all done.

I covered each connection with heat shrink. These are pretty solid.

Then I gathered the wires into bundles, one on each side of the engine.

Other Engine Indications

I connected the Red Cube fuel flow transmitter and the oil temp.

Power to VPX

I connected the wire from the ANL fuse that provides power to the VPX and therefore the rest of the avionics.

ADAHRS Mount

I’m using the Van’s Adahrs mount. This mounts the Adahrs just forward of the next bulkhead aft of the baggage compartment wall. I made sure it was level to the canopy rails before I drilled it.

I put the 3 fittings in the Adahrs and thought it would be easier to install the unit in the bracket before it went up in the tailcone.

Ummmm, no.

The bracket is pop-riveted into place, and I couldn’t get my riveter to some of the fasteners. So I laid there and removed the Adahrs so I could get to the rivets, then reinstalled it. I’m actually pretty sure I’m going to have to remove it again so I can get the Skyview network connector attached.

GPS Antenna

I made a bracket for the GPS antenna that attaches to the engine mount aft of the baffle. I didn’t want the antenna on the glareshield, and with the Adahrs in the back, there was no really ideal place to mount the GPS externally. If I figure something different, this bracket is not a huge commitment.

Com Radio Trays

I decided to mount the Com radios front and center on the sub-panel bulkhead.

Time: 23:15

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Panel continues

July 15, 2020 – Work continues on the panel and avionics.

I started the connection for power to the VPX. This wire will run from the ANL fuse to the power lug on the VPX.

I located and installed the EMS module for engine management. I decided to drill a hole in the sub-panel for a length of conduit so all the EMS wiring can run straight from the firewall back and come in right next to the EMS module.

Here’s the wires coming through the firewall.

I decided to label all the wires in this bundle, so I can just grab the wires I need for a particular component and finish the wiring. I found the pinout and wire list for the engine sensor connector and rang out each wire. This confirms that the pinout is correct, and leaves out the guesswork.

I relocated the manifold pressure sensor from inside the cockpit to the outside, so I don’t have air hoses running through the firewall, only wiring. Then I found the appropriate wires for the sensor, and terminated and installed them.

Time: 9:20

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Antennas

May 8, 2020 – I located and installed the doublers for my antennas.

I bought my antennas from Stein. I got two CI-122 bent whip com antennas, and a 104-12 for the transponder and 104-17 for ADSB. Some people questioned whether I needed an antenna for the ADSB, but I’m going to use Dynon. They require a separate antenna, where Garmin does not.

I located the com antennas under the seats, each in the next bay outboard of the sticks.

I made the doublers for both of them. I used the provided gasket for the hole pattern.

Then I added the attach rivet holes and drilled for the nutplates.

Here’s the doublers in place on the outside of the belly so I could drill the holes.

I dimpled the skin for the attach rivets.

I opted not to use the gaskets; I’ll be using the aircraft skin for the ground plane. Therefore I can paint the doublers.

A friend came out and helped me install them.

I moved on to the two monopole antennas. The ground plane for these will be the skin, but grounded from the inside. So I made small (2.5″) doublers and located them both in the belly aft of the baggage bulkhead. The two antennas are diagonally opposite from each other and more than 2 feet apart, which is the requirement for the ADSB antenna. After I made the doublers, I masked off there locations in the belly, then sanded the paint away, and alodined the skin and the doublers. My friend came back out, and we dimpled the skin and then riveted the doublers in place.

So I’m ready to install the antennas, but I’m not going to so they don’t get damaged.

Time: 7:15

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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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Firewall Forward Items

April 4, 2020 – I dealt with the manifold pressure installation.

To begin with, I moved the MAP sensor from the aft side of the subpanel bulkhead to the front. This gives a direct shot for the pressure tube from the firewall straight into the sensor.

I got brass T’s with the correct dimensions to run tubing at the firewall from the engine MAP line to the sensor manifold on the left side. I bought another manifold block from Vans and used it for the interface.

Time: 2:50

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More Cockpit Work

March 12, 2020 – I installed a couple of items on or near the firewall.

I installed the manifold pressure sensor in the cockpit. Tried to find an out of the way corner. I’ll probably move it to the forward side of the bulkhead, so the hose doesn’t have to bend back to where it attaches.

I also attached a ground bus. This will provide my engine ground and connect it to other grounds in the cockpit.

Time: 1:45

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Continued Cockpit Fuel Lines

February 6, 2020 – At last! A small victory! I have successfully made and fitted two of the fuel lines in the cockpit from the fuel selector to the wings.

A 4-foot length of 3/8 tubing has been whittled down to about 1 foot before I got the hang of this.

I learned that I needed to flare the outboard end of the line IN the airplane.

I made the right side inboard line in an alarmingly short period of time, and it was harder because it has to work around the plumbing for the pump and filter.

I removed the outer kickplate brackets that the outboard tubes will go through. I added holes to each one that would line up with the travel of the fuel tubes.

Time: 3:35

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Continued various Firewall Forward items

February 2, 2020 – I continued work on securing firewall forward items.

I ran the line for the mechanical fuel pump drain. This will vent through the lower cowl, a short distance from the exhaust.

I secured the Red Cube.

I installed the sniffle valve. Not sure how this is going to work out, though, because of its proximity to the exhaust.

A friend came by and helped me secure the clamp for the oil breather tube.

We also pulled the manifold off the firewall so I could replace a 45-degree fitting with a straight one. Maybe sometime I’ll get smart and put nutplates on this…

Time: 2:00

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Moved Throttle Cable

February 2, 2020 – I moved the throttle cable at the firewall so it will come through the cabin heat box at a better location.

I loosened the eyeball in the firewall and turned the cable straighter. The first picture shows the upward orientation of the cable. The second shows how the cable will enter the cockpit through the access panel in the heat box. I’ll put a grommet in that panel later.

Time: 1:10

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