More Avionics Wiring

Today I spent a solid chunk of time routing wires. Making wiring harnesses has been one of my the more satisfying parts of the project so far.

Firewall forward

I started by organizing the firewall forward sensor wires. This bundle contains everything from engine temps, to oil and fuel pressure and the ignition harnesses. These are now secured to the engine mount and won’t be able to move.

On the other side of the firewall I’ve secured everything and routed a portion of the harness down the left side of the fuselage in order to route the wires to proper area.

Center tunnel main harness bundle

This is the center section between the pilot and passenger seats. The main harness here is routed up to the vertical power above for all the power distribution. Other parts of this include all the serial connections, and the electric pitch and roll trim motors.

Here’s another look at all the wires and how they’re routed (Ignore the tie wraps and scraps). The harness splits to allow for the left and right lighting wires to route to the correct wing. I’ve isolated all power wires from my radio wires so that there will be no interference.

Serial Hub

This is my serial hub, it had ports for the primary and multifunction flight displays (empty slots) and the five serial avionics. The ADSB, transponder, Vertical Power, GPS and ELT (black box) all communicate via serial. This hub allows all the components to connect to the two main flight displays in parallel for each of the five serial ports. Once I’m down with all the routing of the wires this will be mounted to the sub-panel permanently.

Fuel pump and selector valve

Once I finished with the wiring I wanted to test fit my fuel pump and selector valve. I have custom fuel hoses from TS Flightlines, so I had to modify the brackets to allow the hoses to fit (you can see the cut bracket on the left below the wires). Once I mount the wings, the two fuel hoses will attach to the fuel tanks.

More Avionics Wiring

Ignition Harnesses

Tonight I spent a few hours making my ignition harnesses. My engine uses twin P-Mag ignitions, so I had to make two identical harness.

I started by removing the connectors on the ignitions so I can attach the wires. The connectors use a screw-clamp style connection.

Right ignition

Here you can see the connector attached to the ignition with the wires attached. This is a six pin connector with Ground, ignition kill, power, and RPM out. There are two additional pins that can be shorted in order to change the default timing of the ignition.

Left ignition

The left ignition connector is on the bottom of the ignition and is a bit more challenging to get to, but I managed.

Completed harnesses

Here are the bundles completed. Looking forward to the day I get to start it up!

Ignition Harnesses

Engine Controls Bracket

Yesterday I spent a few hours making the engine controls bracket. The bracket that comes in the kit is flimsy 0.032 aluminum sheet that is bent so it can attach to the bottom of the panel. I knew I wanted to use something different than the stock bracket, so I made one.

Here you can see the completed bracket. It’s made from 1/4” aluminum angle. It’s very hefty. The three holes are for the throttle, prop and mixture control. The two larger holes have relief cuts made on the back of the angle to allow for the nuts to hold the controls onto the bracket.

I then lined the bracket up with the control panel, and drilled matching mounting holes. I then added some nut plates to the panel so that this can easily be mounted flush to the bottom of the panel. Now it just needs some priming and painting and the bracket is done.

Engine Controls Bracket

VPX Wiring #2

Today I continued with my wiring extravaganza. I didn’t get any new pictures, but I started by beeping out the ELT DIN connector. I originally made the harness a few years ago, and forgot to write down the wire designations. I tested the connector and verified with the specs provided with the ELT and then made the DSub15 connector for the serial bus. The ELT just has serial Rx, power and ground.

Here’s the DIN connector that plugs into the ELT. The tail sticking out is to test the Rx signal. It will eventually be tucked away.

VPX J10 & J12

Here are two of the main power connectors from the VPX. I connected these and began to separate out the bundles by where the wires needed to route.

VPX J1, J2, J8

On the other side of the VPX are the two D25 connectors J1 and J2. These are for some lower power items, like flap position sensor and interior lights, as well as the VPX serial connection. The J2 connector is for all the switches. These will go directly to the panel switches, which will be connected to ground on the other side.

Bundled by function and aircraft location

These bundles are such that each group will go to the same general area of the plane. The lighting harness for example is split into two half way down in order to go to the left and right, for each wingtip. Others are for powering the aft components such as the ADSB, transponder, and autopilot servos.

Switch bundle and serial bundle

This side contains the switch bundle, which heads off to the right side of the image from my hand, and the other bundles are for the flap position sensor, and the serial connection.

EMS and other wires

Here’s a wider shot showing the EMS in it’s mounting location. Once the plane is built this area will only be accessible by laying under the panel and accessing it from below.

The last thing I did was to drill the copilot’s control stick for the quick release pin.

This pin allows the copilots stick to be removed in case the passenger wants a more comfortable ride. There will be two wires coming out of here for the copilots PTT for the radio. It will be fitted with a connector in order to make the system removable.

VPX Wiring #2

Fuselage Wiring

Today I did a lot of wire organizing in the forward section of the fuselage, under the panel. All of the cables routed from the aft fuselage and under the seats funnels into the center section and routes on the floor up to the panel.

Once I organized the rats nest of wires I ended up with two nice bundles. These include the two trim motors, flap motor, ADSB, transponder, ELT, and ADHARS unit. These will be wired to the different serial and power connectors under the panel.

On the right side of the fuse I’ve separated out the radio antenna wire so that I reduce interference as much as possible. This will be behind there side panel from my interior, so it won’t be seen. The RG400 coax wire has a minimum bend radius of 1in, which I am well above in all these bends.

On the left side of the fuse I’ve bundled my two autopilot harnesses. These are separated out from the power wires and autopilot disconnect which will route directly to the pilots stick. The Dynon autopilot harnesses are the standard SkyView Net 9 conductor harnesses except for power. So the only wires needed are the paired data wires.

Here are the Dsub15 connectors for the GPS, ADSB, and Transponder. The red wire for the ADSB and Transponder are left off the connector in order to connect to the VPX. The GPS is powered by the SkyView screens, so it’s fully pinned into the connector.

There are 5 components that use serial connections. In order to connect all the serial to both the PFD and MFD screens, I made a serial bus board that has 7 connections. These are all hooked up in parallel on each pin. When I connect all the connections to the board, each screen will be hooked up to each component properly. I’ve done the pins so that each Rx and Tx from the screens are assigned properly.

Fuselage Wiring

VPX Installation

Yesterday I spent most of the day at the hangar cleaning up and working on the installation of the VPX mounting brackets.

VPX

I started with the rough position of the mounting brackets under the sub panel ribs. This will be the final position of the VPX under the panel.

Each corner needed a nut plate installed, so I match drilled the brackets to the ribs, and then lined up the nuplates and clamped them in place.

I then drilled all the nut plates, deburred, dimpled, and riveted the nut plates to the sub panel ribs.

Here’s the close up of one of the nut plates riveted in place with the angle bracket loosely held in place with a mounting screw.

During the day, a friend of mine visited the hangar to check out the project. He took this awesome picture, thanks for hanging out (and helping) Andrew!

It was fun to chat about the project, and airplanes in general. I always enjoy sharing my love for aviation with other people.

Later in the day, I received a nice shipment from Dynon! My autopilot panel, and my comm radio were delivered! These are some of the final components in my avionics package. The remaining component is the second HDX screen.

AP panel

These buttons are very satisfying to push! I’m looking forward to installing this in the plane soon!

VPX Installation