Chapter 16/22 – Oil heat sub-panel

With my prototype and proof of concept looking good on the oil heat sub-panel, I started off this morning by pulling the trigger on a pair of Korry lights that will show the status of the oil heat exchanger valve on the oil heat sub-panel.

I then removed the left armrest to do some work on it, but before I started work I did a recon of the throttle quadrant to make some mental notes on just how I was going to install the “micro” switches on each side (one that came in from Mouser is definitely NOT micro, but usable nonetheless).  I got some actionable intel doing that assessment and squirreled it away for future implementation.

I then determined the best location for top aft left pilot armrest mounting bracket.  Remember, the plans have these armrests permanently glassed in place, so making them removable is yet another mod.  When I floxed the mounting tabs in years ago, I left the very aft top vertical and also top aft horizontal brackets out since I planned on putting a storage compartment in over the throttle and servo cables, but of course didn’t know that configuration at the time. Now is that time.

I drilled the hole for the armrest mounting bracket and then dug out the foam on the edge around the foam and filled it with flocro.

I also took this opportunity to micro on a foam strip to the outboard top edge where it creates a seam with the sidewall, since that gap is notable.  There’s also a decent sized ~1/16″ gap on the forward edge of the throttle quadrant that I added a thin strip of foam to, also with micro.  I then clamped & nailed the added 2 foam pieces in place.

I found my 0.040″ thick aluminum sheet, cut out a 2.3″ x 4″ piece from that and then prepped it with painters tape before super gluing it to a painters-taped piece of wood… my new favorite work holding method for flat stock.  It was now ready to be machined into the oil heat sub-panel.

I started the machining process by drilling holes into the 0.040″ thick plate… the second pic shows it in the process of being machined to create the oil heat sub-panel.

Not too much later . . . . Voila! The Oil heat sub-panel created.

Here we have the freshly machined oil heat sub-panel all cleaned up. I’ll note that I spent about 10 minutes with a file on the rectangular openings to square the rounded corners.

I then spent a good little bit of time cutting, riveting, making some #6 screw nutplate phenolic assemblies to attach the oil heat sub-assembly to the top of the left pilot armrest.

I then used longer #6 screws and a number of washers (so I wouldn’t have to thread down so far) to secure these nutplate assemblies that I floxed in place onto the underside of the left armrest top for the oil heat sub-assembly, which I also employed to ensure the spacing was spot on.

Since a couple of the screws are right on the edge, as I tightened the screws they would pivot inward and bow the thin 0.04″ plate, so I had to clamp the plate down to keep the screws vertically aligned . . . again, space is SO tight in these birds to cram all this stuff into place!

I then cut the left pilot armrest aft bracket (and the final top mid-point one too…not pictured) and drilled/riveted a #10 nutplate on it as well.  I then drilled smaller holes on the mounting side for flox grips in prep for install .

Over 4 hours later, after I packed the armrest mounting hole area with flocro, I re-drilled the hole, taped up the armrest with clear packing tape, and then mounted the bracket.

Here’s the left pilot armrest aft bracket installed just prior to getting floxed in place to the pilot seatback bulkhead.

Which I did here.  I slathered up the bracket with flox and set it and the armrest in place —Note: to do this it was mandatory that I sand down the foam pieces that I added previously (with micro) to the armrest.  Although I would have preferred to have access to the floxed bracket to clean up any excess flox, etc. I made the decision to leave the removable storage bin in place so I would get no-kidding spacing between armrest, storage bin and newly floxed in place bracket.

I then set the armrest/bracket position by using a spreader clamp and 10-pound weight on top of the armrest.  To be clear, I taped up the surrounding areas on the storage compartment and the cables coming through the front seat bulkhead below to ensure minimized excess flox contamination that might ensue.

With the second to the last mounting bracket floxed in place and curing, I then set my sights on first shooting a coat of primer on the oil heat sub-panel plate.  I then hit it with 3 coats of black paint.  I let that set up for about 30 minutes before then baking it in the oven for an hour at 185º F.  Tomorrow I’ll label and clear coat it so it will be ready for installing the switches, guards and lights the day after.

And with that, I called it a very late night.

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