Chapter 22 Electrical and Avionics (see chapter 17 for throttle quadrant "console")
Note: Label every wire run at each end with actual names and not just a number. You should only use numbers on confined spaces like the bus boards.
June 17, 2016
I just finished the third rework of my wiring system. So I can say, that I am well versed on what's behind my panels, when flying along. When I had the rotary engine with electronic fuel injection system, I had a multitude of wires and a computer with a primary and secondary progaming (which failed) so now I have an IO-360 with a mechanical fuel injection system from Airflow Performance and my electrical system is super simple. I have left and right Bendix 1200 magnetos with a Continental SOS (Shower of Sparks) setup and so once the engine has started, my list of essential power comsuming items is much easier to handle.
Three areas of electrical usage:
1. Start the engine. This takes a master swith on the IP to activate the main power contactor on the FW to send power from the battery to the starter contactor, which is activated by the ignition switch.
2. Main bus power. This bus gets power from the ouput side of the main power contactor, just like the starter contactor. Power thirsty items like the nose lift and electric heat for me and the copilot come from this power bus.
3. Essential bus power. This bus gets power from the main bus pole, but through a diode bridge. If an emergency occurs and electrical power is compromised on the main power bus, then there is a circuit that runs directly from the battery side of the main power contactor through a switch on the IP and to essential bus. The diode keeps the power from flowing back to the main bus. The "stuff" on the essential bus, like the com and the Dynon avionics will have a "second life" to get you home.
4. What if the main bus and the essential bus are "toast"?
As long as I have fuel, the engine will continue to run (mechanical fuel injection and dual magnetos). I have a battery powered Garmin 196 with GPS receiver, that I used when I rented an old Cessna 152 and it fits on the shelf above the IP. I also have an analog airspeed indicator and altimeter, that will give me information to get into the pattern at my home airfield. Did I mention my handheld radio, with headset jack.
and this involves contactor and need for electrical power is focused on See chapter 26 for the EC3 and EM3 sections, if you are doing the Renesis install and the Dynon Skyview install is last in this chapter.
If you blow your fuse in your intercom system, here is a link to save $250 and it real easy to do ( How would I know?) Simple is better 1. battery-at the FW-Fwd side ( Forward side of Firewall) 2. Main power contactor- at the FW-Fwd side 3. Starter contactor- at the FW-Fwd side 4. shunt (ammeter)-at the FW-Fwd side 5. main power bus (fuse type from www.bandc.biz) - under copilot seat 6. essential bus (same as #5) 7. Diode (from www.bandc.biz) 8. IP switches-right the IP 9. Ground bus (three- one under pilot's seat, one on the FW-Fwd and Aft side with a pass through brass bolt (the engine grounds at that point) Note: I had to extend my ground to a point on the lower side of the engine close to the starter to get the best starting power. 10. Wire- Tefzel coated- find your amperage for each item and refer to Bob Knuckoll's book Aeroelectric Connection for size wire, and then the corresponding fuse. Fuses are to protect the wire from burning. front seats in a neat placement that would "fit" in the plane and not violate any electrical "restriction"(longer runs than needed and easy pathways for the wire runs in the fuselage).
Here is great link for wiring the microphone/headphone jacks. I hope that it is correct. I got mine to work.
For the microphone I used :
1. blue for Pilot and copilot mic audio Hi
2. red for pilot and copilot mic key (to PTT) (not used for passenger mics)
3. yellow as pilot and copilot mic audio lo (common)
I grounded the shield to the rear of the Garmin GMA 240
In the video his colors for the microphone are:
For the headphone I used:
1. yellow for the headset audio out right(mine is mono)- stereo would add a wire for the "ring" (middle of jack)
2. blue (common) Headset audio out Lo
and grounded the shield to the rear of the GMA 240
Both of these two are in parallel for the pilot and copilot so as to allow for crew isolation with the Garmin 240
The video does not show the headset audio out Lo for the headphone. Also, the use of the shield as an audio lo is not what I did. The shield is terminated flush at the headset plug and grounded to the rear of the audio panel and also connected to a ground wire running to my IP ground block.
NOTE: If you are wired for stereo and plug a mono headset in to that jack, then you are going to blow the internal fuse on the Garmin GMA 240!
ADS-B=Free weather in flight
1-21-2013: Dynon recently released the ADS-B receiver unit for the Skyview. That leads to some new research on the compatibility of my Mode S transponder antenna and the UAT antenna(for ADS-B). Here are some facts that I have found.
1. Dynon recommends that there be at least 60 inches between the two antenna.
2. Dynon recommends an external antenna for the UAT.
3. Dynon recommends that the ground plate be a minimum of 120mm per side for a square of aluminum for the UAT antenna.
4. The antenna supplier recommends 8 inches (203 mm)per side for the ground plate for the transponder antenna.
5. The UAT antenna is for 978 MHZ
6. The transponder antenna is for 1030-1090 MHZ.
7. "The mode S transponder has the ability for ADS-B out, but that function has not been activated, yet. A different WAAS GPS will be needed for that" (quoted from Dynon).
Here is the link for the supplier of antenna that Dynon recommends:at
With all of these facts, I decided to buy external antenna for both of these. I have installed the UAT (ADS-B) antenna ground plate on the under side of the nose panel and the antenna is on the top of the nose panel. I painted the antenna to match.
The transponder antenna had to be moved to the left strake baggage compartment floor for the ground plate and under the strake for the antenna. I was able to run an coax cable from forward of the IP to that area.
If you put the "Burkut" type strake extensions, then make a provision for wiring to both left and right baggage compartments. This gives you access from the IP forward area to the strakes storage. I put my ADARS (Dynon) unit in the right strake storage compartment and I put my ELT unit, ELT antenna and the ground plane/antenna for the mode S transponder in the left strake area.
Pic#1:This the UAT antenna for the ADS-B on the nose panel.
Pic#2:I did not micro over the layups, since the install of the 120 mm square piece of aluminum (ground plate) is the vital part of this install. The 8-32 studs on the antenna are only 1/2 inch long and so the foam thickness has to be thinned down. I glassed over the ground plate, except where the studs and cable connector contact the ground plate.
Pic#3: UAT antenna
Pic#4: Dynon ADS-B receiver unit ($995)
Note: 01-24-2013 Nose Lift Electrical
The nose gear retract electrical gave me a little trouble. The molex connectors come in two sizes, .063 and .093. The Molex connectors for the nose lift are .063 size connectors. I could only find .093 size molex connectors and so I switched out the
9 position male and female interlocking connectors for that size. Buy the tool from B&C and do the heat schrink and then try to not get comfused on pin positions.
Pic#1: The wiring schematic is color coded for male and female sides. Jack says that color of wires may vary. Also the size wire will change from the male side to the female side of the connector (go figure). All of my labels were still on the wiring harness that came for the IP switch and for the female side of P-2 wiring harness and so the wires for the female side of the connectors could be placed accurately. On the top right, the pin assignment is marked, but there is no top side marking and the connector is a perfect square and so if the colors for the female side vary, then you just have to study the male side of P-1 and P-2 to mark the plugs for #1,...
Pic#2: NOTE:There are two blacks and two reds on the male side of P-2, so mark the pin number on the wire, before you cut it off. If you forget, the same color pairs of wires are not the same size diameter and so you can still sort them out.
P-2 is sitting over the schematic like it will run. It would be nice to have a wiring diagram for an average install in a Cozy.
The remainder of the wires on the female side are shown in pic #3.
Pic#3: This shows the female side of P-2 on the left and the male side of P-2 on the right making the short run to the installed Automatic Landing Gear Extension box. Beneath that box is the installed Dynon Mode S transponder (the transponder antenna is mounted below the aft portion of the left strake storage area)
In the pic, on the female side of P2 you can see a yellow wire marked as "P1-8". That wire runs from P1-8 and terminates at P2-2 and another "P1-8" yellow runs from the IP switch. I would like a label like P1-8 to P2-2 for one of the yellow wires and IP switch to P1-8 for the other yellow (the two wires are connected in their runs). Study the schematic a few times and mark your color of wires there and triple check as you run these wires.
Also note: The roller switch wire connections are subject to being knocked loose between the install of the lift and the electrical work (years later). The bottom color on the left one is red and on the right bottom one is orange ("C"on the schematic).
Pic#4: The IP switch.
Pic#5: The manual extension rod is located next to the bottom right corner of the pilot's Dynon 1000 display.
The two hardest decisions for the project are the avionics and the wiring schematic and diagram.
I am installing a Dynon dual 10" size screen setup and adding backup analog instruments. My engine monitor and controller is from Real World Solutions (aka Tracy Crook).
Some builders use a panel design software, but I cut out templates for the IP footprint of each item and then I
taped them on a plastic transfer on my shop wall. You will be surprised at how many "tweeks" that will be needed.
Componets and physical location in the airplane
Note: Fuses or breakers.
You decide. I had a long spiel on this , but I deleted it, because it is not a big deal. I like the fuse buses as long as I can have a primary and secondary circuit for the engine.
Tools from BandC:
The two pictured above are the most important tools. The crimping tool has a torque adjustment and it only goes to that pressure and then releases. The stripmaster has a hold bar and a strip bar and they move apart with the first half of motion and then the hold bar releases the wire at the end before the return motion starts (so that you don't bend the exposed wire). Don't scrimp on these for cheaper versions. I have the cheaper versions from before this project.
1.PIDG Style Crimp Tool (RCT-1)
2. Ideal Stripmaster (45-097)
these first two are the most important
3. BNC Coax Connector (RCT-2)
4. D-Sub Machined Pin Crimp Tool (RCT-3)
1. 1/2" wide copper bus material (from AS)
2. Brother P-touch PT-2030 (labeler from Staples)
Here are some pictures of what is on the IP.
Thanks to Ben Myburgh, IFR instructor, for his help in the panel selection. The core of the panel is the Dynon Skyview system and the Garmin 430. Next shown is the Garmin 240 audio panel, then the Garmin SL30 Nav/Com. The Dynon system has a built-in mode s transponder (which allow TCAS symbols to pop up on the display with warning signal and altitude positions realtive to my position). The pilot side will have the 10 inch primary display and the copilot side will have the 7 inch display. That leaves more room on the copilot side for switches and breakers.
Pic#1-3: The IP layout is dependent on not cutting off the Todd's canopy and moving the LE of the canopy forward. This gave me the option to make a cover area that allows 4.5" of room forward of the IP. Because of that I can install an altimeter, air speed, Trutrak attitude indicator, and compass at the top of the IP. Most switches are in a module to the right of the avionics stack. The manual retract rod is angled above the IP and goes between the AS and Trutrak instruments. I have the Dynon dual Skyview systems, but I will have analog (aka "old school") instruments as backup. The truth for me is that I prefer to look at an analog altimeter, when I check for pattern altitude and I will probably use the United air speed indicator for the pattern. I like the GPS and autopilot also and will take the work reduction on cross country flights. I am not yet IFR rated and so all of that will change my IP usage, at that point. The top lip on the IP is ficro (78% flox and 25%micro) and after the Zolatone, it looks really smooth. I am going to add a vinyl wood finish to give the IP the "British sports car look" like my old MG.
Pic#1-3: I used 6"X48" pieces of adhesive backed cherry flooring from Lowe's. It cost $2.88 per piece and it took 1.5 pieces to do the IP for a cost of less than $5. On the left and right ends, I made a paper template to start and end. The rest of the time, I pressed the piece against the IP (with the paper still over the adhesive back side) and used a dremel disk to cut the straight lines and I used the same round bits that were used to cut out the IP to cut the round holes. If you mess up a piece, it's no big deal. I messed up one. This really looks great on the IP.
Pic#1: You can see the marked cutouts. You can drill the mounting holes for the instruments after the vinyl is installed. I had to drill for the parking brake bracket and install it to help me when I used a drill bit on my dremel to cut the channel in the vinyl.
Pic#2-3: I used some graph paper and made a template for even spacing of 12 switches in about 3"X 6" of space and then cut out that section of the IP, so that I could reduce the thickness (pic #2). I added a two ply BID layup on the forward side of the IP. Next I drilled 1/4"holes and used the 1/2"Dewalt bit with the 1/4"tip guide. Pic #3 shows the transfer of the holes to the vinyl. I held the IP piece in place and then marked some of the holes onto the vinyl piece. It is all very particular, but hey, you can just get another piece of vinyl and quickly redo this one piece. Running the vinyl strips up and down, decreases the risk factor on errors and makes it so much easier.
I added the backups of airspeed, attitude and altimeter.
Westach 2 1/4"Dual Volt/Amp Gauge
Falcon Fuel Gauge (single input)
Since I added the header tank and cross connected the left and right fuel tanks (at a lower level than the tanks), then each sensor should send the same level as if I had one fuel tank (I will do some testing to verify this, before the first flight). If I can input the Princeton probe signal from one tank to the Garmin 430 or the Dynon system, and send the other probe output to the Falcon single tank gauge, the I have redundancy on fuel level information. If there is a tank imbalance, then the Garmin 430 and the Falcon gauge will not match on amounts shown. If the Garmin 430 and Dynon system crash, then I will still have a fuel level figure to work with along with the analog instruments to navigate with.
Airpath C2300-L4 Compass Lighted (AS 10-01341)
Attitude and bank indicator: Trutrak ADI-3 W/GPS (AS 11-05654) The depth is 4.6"and that will fit for me.
(This inst. does roll, pitch, direction with a low airspeed flashing indicator in the direction slot when needed. There is a serial input for the GPS to run off of the Dynon GPS, but as a backup, it will use it's own GPS. Great backup to get you home, when the Dynon system shuts down. I will also carry my little Garmin 396.
Atlimeter: Digital Taskem 2000-3 (AS 10-24080)
Airspeed Indicator: United True airspeed ASI 40-260K (AS 10-00201) (14V Light Tray AS 10-00111)
The mounting system for the avionics is a simple setup of two pieces of glassed 1/4" thick foam. I added two Tee nuts for the avionics racks to attach to. These two pieces added support to the IP, which needed it after it got the "swiss cheese syndrone".
I found that I have a 7 inch usable height of space in the center of the IP. With the Garmin 430, 240 and SL30, in that space, I still have about 1.75 inches not used. This is due to the rear mounting of the Mode S transponder with the Dynon system. In the 18-20 section and pic#2, you can see that the shaft for the manual LG extension has been moved up to the top of the IP to give more space. If you put that shaft at the bottom of the IP and you have a failure of the main worm drive bolts (hard nose landing) then the strut is going to shoot that shaft aft by several inches. John Slade had an injury to his hand in this manner.
Simple is better
1. battery-at the FW-Fwd side ( Forward side of Firewall)
2. Main power contactor- at the FW-Fwd side
3. Starter contactor- at the FW-Fwd side
4. shunt (ammeter)-at the FW-Fwd side
5. main power bus (fuse type from www.bandc.biz) - under copilot seat
6. essential bus (same as #5)
7. Diode (from www.bandc.biz)
8. IP switches-right the IP
9. Ground bus (three- one under pilot's seat, one on the FW-Fwd and Aft side with a pass through brass bolt (the engine grounds at that point)
Note: I had to extend my ground to a point on the lower side of the engine close to the starter to get the best starting power.
10. Wire- Tefzel coated- find your amperage for each item and refer to Bob Knuckoll's book Aeroelectric Connection for size wire, and then the corresponding fuse. Fuses are to protect the wire from burning.
front seats in a neat placement that would "fit" in the plane and not violate any electrical "restriction"(longer runs than needed and easy pathways for the wire runs in the fuselage).