Chapter 22: Electrical/Instrument Panel (Work in Progress)
Planning out the Instrument Panel
I put paper EFIS and radio controls on my instrument Panel (IP) early in the build to help with the dreaming/motivational aspect of building. By the time I finished painting the interior (see finish Chapter 25, which I did out of order) I was ready to start work on getting the panel laid out for real. I kept ideas over the years of work, looking at what others have done, and refined it for the decisions I'd made above. Once I had a rough Powerpoint layout I liked for the big parts and the switches I traced a paper template of the IP and got the ruler out and drew in all the switches and taped on the EFIS and radio candidates then taped it back up and put pillows in the pilot seat to mimic my planned sitting position. After getting used to this a few days, I moved a few things around a little on the paper template, then used it to drill the switch holes and install the switches and warning lights. Here's a view of both the paper template early thoughts on layout of avionics. I'd bought the switches at this point, but still not the EFIS or radios, etc.
Switches and EFIS Installation
I tried to flat black paint the IP, but I just didn't like the way it looked since there was too much underlying fiberglass texture that was not uniform around the periphery. I also wanted to do good lettering. So I followed the lead of Bernie Siu and others by developing a vinyl print from a local printing shop. I used the paper template shown previously to CAD-up a pdf file that I had printed at a sign shop on vinyl and my wife helped me get it applied to the IP without bubbles (it's definitely a 2 person job). Make sure the surface is very smooth and clean to enable the vinyl adhesive to gain a strong grip. I had already cut all the switch mounting holes with a drill, which meant that I needed to use a razor blade to cut the little vinyl circles out in front of each hole (as well as the holes for the air vents). This wasn't hard because you could feel and see the hole edges with a little angled light. Cutting the IP for the EFIS and radio (below) was done by first mark/trim the vinyl with razor blade, remove the vinyl rectangle, then cut the IP with dremel wheel and corner grinder.
It was at this stage that I made the purchases for the EFIS and radio/intercom. I'd pretty much decided to use Dynon Skyview (SV) and splurged on the HDX1100 and followed Neal Johnson in using the Garmin GTR200 radio/intercom. It's a not an inexpensive approach, but is pretty well integrated and I liked the layout of the Garmin over the SV radio option. Both however are good. You will see I use "EFIS" and "HDX" interchangeably from here on through the website.
After a week of working on wiring and occasionally sitting on pillows getting a feel for the cockpit, I realized that the EFIS view angle is not ideal (my opinion) when mounted flush in the IP. This is in part because I want my eyes relatively high locking over the panel and down the sides and the screen is facing my lower chest. I noticed someone a couple of months prior on the builders email list talking about tilting the IP top forward a little to improve this view angle for modern screen based avionics. Since I'm not going to tilt my IP at this point, I decided to look into tilting just the EFIS. The result with a couple of 6061 Al 1/16" thick sheets is shown to the right. At this point the screen is facing my neck, which feels much more comfortable a viewing angle. It's firmly mounted to the panel and I painted the Al plates black to make them harder to see (pictures to right)... Word of Caution: Tilting the bottom of the EFIS out like this does reduce it's clearance with your shins when you bring your heals up close to the IP. I tested it, and it was fine for me, but probably will require more care to manage in and out with a taller pilot. I've considered making this a movable tilt, so that I can push it flush with the IP whenever I want, but that will be a mod for after Phase I flight testing...
Powering Up the HDX1100 and Integrating the Skyview System
Before doing anything with the EFIS/HDX I worked on getting all the switches and other circuits checked from the VPX (see Ch 22 page). Then I connected the HDX to the VPX and it powered up perfectly when the Master Switch was closed (note the SV-HDX EFIS is designed to be connected this way and has it's own battery backup, that I also had wired up before booting the EFIS the first time. The HDX1100 has these other components connected to it as outlined below:
SV Transponder: This unit is powered by the VPX when I close Avionics switch on the panel. Pilot control is through the EFIS and the actual transponder box is located on the same shelf as the VPX. I built the connector for power from VPX, ground, and data exchange with the EFIS as well as buying a BNC/BNJ equipped RG400 cable of 35" length and used the Archer dipole antenna mounted as far forward as possible in the nose co-pilot side wall. This remote transponder module is mounted on the same shelf as the VPX, fwd of the copilot side IP.
SV ADAHRS: My ADAHRS is mounted under the pilot's thigh support, where it's easy to run the pitot/static, OAT, and Skyview net cables and it's very close to the CG of the airplane as recommended. This location is also at least a couple of ft away from the nearest actuator (pitch trim) and 4' ft away from the nose gear actuator. After completing the plumbing of the pitot and static lines to the ADAHRS, I connected the OAT sensor and mounted it inside the pilot side NACA vent. The sky view Net cable was made from a SV-NET 10 ft one ended cable by cutting to length (~ 5ft) and crimping all the right pins in the 9pin D-Sub connector.
SV Engine Monitoring System (EMS): I considered a lot of different places to put this little box and ended up choosing a place I hadn't seen anyone use. I built 3 BID mounting flanges on the forward face of the main spar on the pilot side and mounted it there to keep it off the firewall (where I wanted to mount the bigger Engine Control Unit from UL. Both will need to be pretty close to each other and the firewall so the Skyview Network cable would need to be 10 ft to reach here. I bought the one-ended network cables from Dynon and made the connectors to go in the EFIS. The 10 ft version was just the right length when running in the pilot side electrical conduit path.
SV GPS 2020: I also looked at a lot of options for placing the GPS. I chose to put it in the canopy high behind the turtleback bulkhead so it had maximum view of the sky and was away from the transponder and radio. I designed a custom bracket and 3D printed it to attach to the bulkhead there. I'll have a wiring connector at the canopy hinge line for canopy removal. This is waiting for when I get the canopy back out of storage...