Anxious to get on with the wiring, the paint booth was cleaned, the plastic walls rolled up, and wiring started as soon as the fuselage was painted. Getting the painting done was such a relief.
Then it occurred to me: once wired, the boot cowl would need to go in place before the engine could be hung. I had not painted the boot cowl. More troublesome, the days were getting cooler and the time to get it painted was growing short.
So the wiring came to a halt. The plastic was unfurled, the fuselage was moved out, and back to painting. Ugh.
The etching primer went on easily, followed by the PPG polyurethane paint. The results were a pleasant surprise: it looked car – like in its quality. DSC_0070.jpg
But the bottom portion of the boot cowl needed to be painted silver to match up with the fuselage, so the boot cowl was temporarily placed on the fuselage and the location of the silver paint line determined. The Polyfiber Poly Tone went on easily. While the paint booth was set up, the landing gear components were also painted Poly Tone Nevada Silver after buffing with a Scotch Brite pad and spraying the powder coated surfaces with Bull Dog Adhesion Promotor. The plan is to finish the wiring, install the landing gear, then install the boot cowl, followed by the engine. That should take me through winter. DSC_0105.jpg
The moral of the story: don’t forget to paint the boot cowl before moving on to the fun stuff.
A pattern was made scaling it to size from the pattern on the website on a piece of grid marked poster board. (I have previously commented on that stuff. It is really handy). The pattern was carefully cut out, since both the inner and outer portion will be used.
The outer portion (which marks the area to be painted) was used to cut away the protective wrap about a half inch inside where the paint edge will be. This was done with a scissors. We avoided touching the plastic window with a knife or any sharp object whatsoever.
The area to be painted was sprayed with Bull Dog adhesion promoter and permitted to set up for a few minutes per the instructions, then followed with the finish coat of PPG Polyurethane. The plastic was placed on a vertical board, suspended with a nail through the flap hole, to minimize dust settling on the surface. It came out well. What I don't know is how durable it will be.
Thanks for your tip some time back about securing the nut that controls the throttle arm so it could be adjusted from the finished side (so you don't have to get behind the interior panel to tighten or loosen). I probably would have missed this.
But I wonder how long that type of nut plate will hold up to repeated adjustments? My thought was the nylon nut would hold up longer and when it did not hold replacing it would be easy.
Anyone that built a Heathkit in the late sixties will remember the yellow covered instruction manual. Each connection had a separate line with a box to check after it was done. When all the boxes were checked you could be confident that it was properly assembled (except for the rare cold solder joint). Heathkit pretty much mastered the idiot proof instruction manual.
The G3X does not come with such an assembly manual. What it does include are harnesses with each wire clearly marked and a set of wiring diagrams.
So here are a few general tips:
1. Keep the rotator! It is so much easier wiring when the plane can be flipped on its side to access hard to reach areas, like under the seat.
2. Resist the urge to set the panel in place until the power harness is routed, the area under the seat is wired, and the backup battery holders are assembled and installed.
3. Wire the area under the seat first. Note that the relays go on the left side, not the right. The 40 amp breaker can be secured with Methylcrylate or two part epoxy since a screw head may interfere with placement of the fuse. We did not glue this down until everything was zip tied and secured in place so that it would be in its ‘natural’ location with no tension on it.
4. Route the power and lighting harnesses first. If you place the G3X harness before the foregoing are installed it gets a bit crowded.
5. If you are adding the GDL 39 ADS B In, install it before mounting the avionics tray. It fastens to the bottom of the transponder frame and is much easier to install outside the plane.
6. With the foregoing complete, set the panel in place, holding it with clamps or wire ties. It will need to be adjusted once the boot cowl is in place and only then can the Adel clamps be installed.
7. Remove the G3X, radio and transponder when wiring the panel. The G3X is held in place with four screws and is easily removed. The transponder has a single screw on the aft side that is removed and then the arm rotates, releasing it. The radio is removed be inserting a 3/32” hex wrench into the small hole on the lower right side and unscrewing it. [This information came from the manual, which can be found on line. Hard copies of the Garmin manuals were not included. The G3X manual alone is over 750 pages long.]
The ADHARS was placed on the instrument tray, contrary to the diagrams that indicate it goes under the seat. (I suspect the diagrams may be revised by the time you read this). Nut plates were riveted in the four corners of the instrument tray, part number MS21055-3. (We ordered them from Wicks). The ADHARS mounting holes look like they are symmetrical, but they are not. The holes will only line up if the ADHARS is placed with the plug sockets on the inboard side. AN3-10A bolts were used to secure it in place.
After the wiring is complete, the pitot and static lines were added. Because we added an ASI and Altimeter, those gauges were connected as well. The lines will be tied down more securely after the GPS20A is installed.
1. There is a shunt in the middle of the tray. We shortened the wire from the harness, PO3A10BK, and placed a terminal that would fit on the large bolt of the shunt. Note the insulated covers. The two fused wires, GEA10A22 and GEA11A22, are connected to the small screws on the back side of the terminal posts. Note carefully where they go: if reversed the current will read backwards on the G3X.
2. The G3X back up battery hangs from the ignition back up battery, which means the fabric we had so carefully extended forward had to be cut to gain access.
A curved section of thin aluminum about a half inch wide was cut to provide support for the fabric. The fabric was cut, folded over and poly brush used to hold it in place. The only time this will be seen is when the interior kick panel is removed to access the backup batteries but we wanted to keep it looking neat and the fabric taught.
The GDL-39 was added for ADS-B In. It was mounted under the transponder using the brackets provided by Cub Crafters. The connections were positioned forward, away from the pilot. It is best to install it before installing the avionics tray.
The power line, with an in line fuse, was connected to the avionics bus. It will only be powered when the avionics switch is on and is not in the emergency power back up circuit for the G3X.
The GDL-39 antenna was mounted on the bottom of the belly pan. Note this is a dual band antenna; needed for reception on the two bands for ADS-B in. The feed line was run on the left side, opposite the transponder line, to minimize the risk of interference. In order to wire tie the coax cable on the vertical frame member, a half oval notch was cut out of the interior panel matching the cut out on the right side panel. A quarter inch standoff was used so that the panel could be easily positioned without interference from the cable.
The two ignition modules set side by side. One must be designated left and the other right and subsequent wiring then follows suit. We came up with a rather clever system for determining which was which: the one on the right sided was “right” and the one on the left was “left.”
There are two green wires from the main harness that must be wired into each of the plugs on the two ignition modules. This requires that the harness plugs be dismantled, the correct pin located, and soldered in place. A thin section of heat shrink tubing was placed over the freshly soldered joint and the harness reassembled.
The left and right warning LEDs are wired with a tiny capacitor (described as a ‘radio filter’ on the wiring diagram) and sort of ‘hang’ behind the panel. A bit of heat shrink followed with spiral wrap worked well.
Re: Chuck and Ryan's Build Tips
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