N254MR

At last, after a number of quirky twists and turns, the panel overlays are complete with lettering and top clear coat, ready to install switches and lights! Wahoo!    The largest bunch of spaghetti left to nail down is on the left side, waiting for the switches. Full steam ahead!

Except for the minor job of bolting down the D-sub connectors on the chassis (as usual, waiting for just the right hardware) the relay box internal wiring is all done. Relays 1 and 2, along the bottom, are used in the elevator trim control system. Relay 3, on the right side, is for the flaperon control system.

The ground power protection circuits on the top of the relay box cover are essentially done, ready for installation. From left to right are the Schottky diode for polarity protection, the Powerlink III Jr. solid state relay, and the Perihelion Design linear over voltage protection device (OVP). The ground power panel switch applies (external-sourced) power to an inline fuse, then to the right quick tab on the OVP. As long as the voltage is within limits, it passes through the other quick tab to power the relay. The high current ground power will pass through an inline fuse near the inlet, then to the big stud on top center of the Schottky diode, through the little studs on the sides, then through the BATT and LOAD terminals of the relay. The LOAD tab will connect to the BATTERY BUS. (As usual, all quick tabs and ring terminals have been lightly coated with Tef-GEL for corrosion protection.) All the wires that will be "permanently" attached to this cover plate are in place. The others will be added at installation time, and disconnected if it's necessary to pull the relay box or its cover devices out for maintenance.

The "relay box" is coming together. Counter-clockwise from lower left are relays 1, 2, and 3, the panel LED flood resistor board, the low voltage warning and auxilliary battery management module (there's a mouthful, better to call it the LVABM) and finally, the linear over voltage protection (OVP) device. The latter two black epxy-potted devices are both from Perihelion Design. (Whether there will actually be an auxilliary battery is dubious, but the special management functions are part of the low voltage warning device, so I'll wire them out to the D-sub connector in case an AUX BAT is installed at some point, weight permitting.) These devices will all be wired through the D-sub connectors on the left side of the box, except for a couple of higher current wires that will come in via a rubber grommet. Soon, this view will be, uh, somewhat obscured by a whole bunch of wires -- more than 40 (!) -- between these devices and the D-sub connectors. Good time to take a picture now while we can still see something.

Around the edges, you can see the blue Click Bond nutplate "nipples", which are there while these #6 nutplates for the cover plate screws cure. The relay boards will be part of flap control and elevator trim servo speed switching  circuits. Between relay 3 and the resistor board, and between the two black Perihelion potted devices, you can see two other Click Bond nutplates that will hold the top bracket for the ARINC module, which mounts behind this box. When installed behind the panel, this view will be toward the right side of the airplane, with the firewall on the left.

Beginning the process of applying lettering. Here the right "wing" or side panel is shown laid out on a piece of poster board. I have a horizontal reference line drawn to go through the lower set of device holes. In the upper right is the hand burnishing tool obtained from a leather craft store.

Here the letter set is laid over the panel. I've lined up the alignment or "registration" marks on the letter set with the horizontal line on the poster board. However, it looks like the letters above the AUX PWR outlets on the left may be too close to the flange of the "cigarette lighter" plug outlets, one of which is sitting at the top of the picture to eyeball the clearance. So I need to raise the letters about 1/8" higher than originally planned.

Here I've drawn a second (dashed) horizontal line 1/8" above the first one, and moved the letter set white line alignment marks up to meet it.

The "relay shelf", which was started months ago, is finally coming together, just in time. This view looks at it from the firewall side, looking aft, i.e., the side most of the wires go to. Left to right you can see a cluster of some (but not all) of the discrete components that will go inside the larger of the metal boxes, including the panel flood LEDs resistor board, and various flap/elevator control relays. Next, on top of the gray primer-painted shelf, are a few things in what will be their final positions, to fit underneath the right cockpit corner wrap, including the ARINC interface box, up on edge, with a gray angle on top to secure the top to Click Bond nutplates inside the large aluminum box, then the box with multiple D-Sub connectors for the gear that will be inside. (Not shown are the low voltage and over voltage protection devices that also go inside.)

To the right is the cover plate for the box with ground power polarity protecting Schottky diode, ground power relay, and FPS-Plus-Reflex flap controller (white box.) When the internal components are mounted and wired to the D-Sub connectors, it will be ready for final assembly, though I'll take several more closeup shots first as a record of the assembly sequence.

Finally got all the panel grounds terminated, all 33 of them...yikes! Fortunately, that doesn't mean there are 33 devices behind the panel, because several of them have multiple grounds, including the EFIS's, the 430W, the FPS-Plus, etc. Still, it's a lot. On average, at my speed each one takes about 5 min. to do, what with final routing to the quick tab, heat shrinking, crimping, anti-corrosion treatment, labeling, and logging. Have also been working on last minute tweaks to the "relay board shelf" that goes behind the right side of the panel, installing Click Bond nutplates, wire clamps, etc. I'll need to assemble it completely before installation in order to take comprehensive photos for documentation, because some devices on it will not be readily visible once it's installed. In short, wiring the right side of the panel will be done soon. Final panel lettering should arrive tomorrow, so actual panel and device installation is nearing too.

The diagnosis has been made. I am suffering from wiringitis. It's akin to hoarding. The key symptoms are repeatedly declaring the installation of wires to be complete, and then adding more. There is so much temptation feeding this addiction -- in the form of little wires & pins on the connectors of all the electro-whizzies -- that are just begging to be utilized. "Hook me up, hook me up too!" they scream. And the more whizzies you have, there's an order of magnitude more wires and pins, representing actual or imagined functions, that lure you into installing more wires -- stubbed off, unconnected even -- just in case someday you get around to really "needing" that function.

Perhaps an example will help explain this affliction. I have a CO Guardian Model 353 carbon monoxide detector/alarm. It's a tiny panel mount unit, to be located over on the right. It has a built-in light alert and a high decibel audio alert. You might think that in a little two-seater, that would be enough, eh? But no. You see, it also sports other outputs in its sneaky little D-sub connector. These include two (!) separate relay outputs, for switching something else on an alert, and (ta-da!) even an RS-232 serial data output for the EFIS to display a continuous running count of the actual CO parts per million, whether dangerous or not! At first, I thought the built-in alarm would be more than sufficient. Then I thought, well, it would be nice to at least integrate the alarm with the EFIS alarms, which meant adding a pin and wire to one of the relay outputs, running to the EFIS switched trigger inputs. Fine.

A lot of progress today, first with terminations on the "forest of ground tabs". These are really the first significant terminations done on the cockpit side of the firewall and it does feel good to get going on them. Each termination has multiple layers of heat shrink for strain relief, a label, an overlay of heat shrink covering the connection itself, and each side of each tab has a thin film of Tef-Gel(tm), an anti-corrosion gel.

A very long evening, resulted in the center sections of these cross-panel bundles getting pretty much done. Very time consuming because some of the wires within those crossing bundles are already terminated at one end of the wire (which I call "break points") such as in avionics harnesses, or the through-firewall passage, and some are already terminated to the right, some to the left. They must all be pulled snugly and cleanly from whichever direction is still unattached to get a smooth running bundle. The remaining terminations come later. I'm using spiral wrap on all these lower, crossing bundles for extra chafe protection because they run past airframe component edges... and even though they'll be quite high, they could get inadvertently kicked. About the time these center runs of the various bundles are completed, the panel itself should be ready to begin installing switches and a few small wiring harnesses which will be actually mounted directly to the panel overlay pieces, such as for the bank of annunciator lights above EFIS 1.