Tidied Up Firewall Forward Wiring

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I got an order from McMaster Carr that included some more silicone adel clamps along with some tefzel zip-ties.  I installed a few to secure all of the wires near the right firewall pass-through.

This nicely tidied up the EGT, CHT, and Lightspeed Ignition wires running across the upper engine mount tube.

I also replaced a bunch of the temporary nylon zip-ties with the tefzel.  Regular nylon zip-ties are only good up to about 185º F.  Black, UV stabilized zip-ties are better at up to 221º F, but tefzel is good up to 300º F.  There are even higher rated zip-ties such as PEEK which is good to 500º F, but they’re over $3 per zip-tie!  All of the wire insulation in the plane is also tefzel insulated, so if it’s hot enough that these zip-ties melt, I’ll have other problems.

I also finished up the Dynon GPS mounting bracket.  I put a gentle radius in the lower flange to follow the curve of the engine mount and drilled a few lightening holes.  I then primed and painted it gloss white.

Installed GPS Mount and Started Instrument Panel

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With the mounting bracket painted, I installed it on the engine mount.

The EGT and CHT wires from cylinders 1 and 3 run under the bracket and pick up the GPS wires.

There is still plenty of access to the back of the engine for oil changes and maintenance.  I like this approach so much better than the shelf that many builders go with.

I then finished up securing the wires along the top left engine mount tube.  This bundle picks up the oil temperature sensor, manifold pressure sensor, oil pressure sensor and fuel pressure sensor wires along the way.

I’ve been working on my panel layout on and off for many months.  I’m happy with it now, so I started transferring it to the panel this afternoon.  You can’t see much here, but my computer model was perfect.  Everything fits exactly as it should with the clearances I determined in the computer.

Here’s a rendering of the panel from the modeling software.  The only thing not pictured here is the hobbs meter.

Resumed Work on Baffles

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With the cowling fit, I resumed work on the baffles.  After a little trimming where the baffles fit around the rocker arm covers, I got everything mounted to the engine except for the part behind the spinner.

I had previously cut off the flange from the aft baffle support since it pushed the aft baffle walls too far back.  I fabricated I replacement from some 1/16″ angle stock and riveted it to the baffle support.

To ensure the aft wall is in the right spot, I clamped a straightedge across it.  I then clamped the bracket to the wall and drilled the holes.

With the aft baffle wall bolted to the support, the back wall becomes very rigid.

I made the preliminary angled cuts on the ramps and made the necessary bends in the forward side baffles.

With a little trimming back of the side baffles, I got the cowl to fit down behind the spinner.  You can see that it’s still nearly 1″ too high, so I’m going to have to cut off quite a bit of material to get the cowl to drop all the way down and then further to have the necessary clearance between the cowl and the baffles.  The engine can move around quite a bit due to the flex of the engine mounts, and you don’t want the baffles to contact the cowl.

The standard way to trim the baffles is to line the top with paper clips and then put the cowl on top.  The cowl will push some paper clips down more than others. You can then measure down some amount from the top of each paper clip to create a cut line that perfectly follows the curvature of the inside of the cowl.

Trimming Baffles

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No pictures tonight, but I went through a few iterations trimming the baffles.  The cowl is quite a bit lower, but still not all the way down.  I probably have at least 1/2″ to go if not more.

I also started trimming the ramps.  I have no idea why they give you so much extra material; you have to cut quite a bit of it off before you can even start bringing the lower cowl up into place.

Ramp Crossing Bends and Instrument Panel Prep

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I trimmed the forward ends of the ramps to within 1/2″ of the final dimension and them marked them for the crossing bends.  These bends allow the ramps to follow the slope of the cowl inlet.  The ramp on the left side is pretty deep since the air filter will be installed here.

The ramp on the right side is quite a bit shorter since the #1 cylinder is farther forward.

From the back side, you can see that the ramp follows the slope of the cowl inlet.  The ramp will get trimmed to be exactly flush with the inlet and a piece of baffle seal material will bridge the gap to prevent air from leaking.

I also trimmed off 1/2″ from the top of the Experimental Air throttle bracket so that I can have a little more knee room.

I’m going to have this TIG welded to the bottom of the instrument panel, flush with the front of the panel.  I’ll grind the weld flat so that this will be a seamless transition once painted.

Finished Tailcone Wiring (For Reals)

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I thought I finished all of the tailcone wiring a couple of weeks ago, but I had forgotten about the OAT probe and ELT antenna cable.  I drilled a new hole in the vertical rib for the antenna cable to avoid too tight of a bend radius.

On the right side of the fuselage, the cable follows the tubing run and then jumps over to the tailcone wire bundle and follows it into the conduit.

I also installed a couple of adel clamps under the seat.  This one supports the wires and tubing as they come out of the front end of the right conduit.

I installed another one on the other side of the same rib to keep the tubing from interfering with the aileron pushrods.

I also installed a couple of zip-tie bases in the aft flap cover to support the flap motor and position sensor wires.  There are not installed permanently right now, but I wanted to anchor them so that I could determine the final wire length.

Finally, I recreated my upper left switch layout with some scrap aluminum to make sure I was happy with the spacing.  I spent a few minutes playing with it and I think it’s perfect.  The spacing I settled on was 1 1/4″ horizontally and 1 9/16″ vertically.

Received Avionics Stack

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I picked up my avionics stack from Aerial Avionics today.  They’re a local company, but they were willing to match a price quote from I got from Stark Avionics.  I got a PS Engineering PMA 8000BT audio panel and a Garmin GTN 635 GPS/COM.

They built the wiring harness as well.  I went through the whole thing so that I could fully understand all of the interconnects.  Other than installing an unnecessary marker beacon antenna cable (which I removed), everything looks perfect.  Despite what looks like a rats nest, these are nicely organized and grouped together according to where they need to be routed in the airplane.  The only mistake I made was forgetting to request that they use red wires for power and black for ground like I’ve done with all of the other avionics in the plane.

Fabricated Avionics Stack Mounting Brackets

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After carefully aligning the trays, I drilled some 1/16″ angle to them so that they can be mounted to the instrument panel.

The 1/16″ angles are set back by the thickness of the instrument panel.  Using a piece of scrap here the same thickness, you can see that the faceplates of the radio will be flush with the front of the panel once installed.  Next up will be to cut the hole in the panel and subpanel for the avionics stack.

Started Cutting Panel

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I wanted to get started cutting the panel tonight.  First up though, I needed to fill two of the holes that are normally used to attach the panel to the ribs.  Since I’m moving the ribs inboard, these will no longer be used.  The top holes on each side (and the one in the middle that is normally used for the canopy ejection handle) all fall within avionics cutouts, but the bottom holes on each side will be visible beneath the SkyView screens.  I countersunk the holes and installed AN426AD5-4 rivets in them.  When I prep the panel for paint, I’ll sand/fill this so that it will be invisible.

I then cut out the hole for the avionics stack.  The hole is really tight vertically now (and just right horizontally).  I’ll extend the bottom edge of the hole down 1/16″ or so to make a little more room.

Along the side, you can see that the avionics are completely flush with the panel.  Once I move the stack down a tiny bit, I’ll line up and cut the holes for the SkyView panels.

Cut Holes for SkyView Screens

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I extended the hole for the radio stack downward by 3/32″ and then cut the holes for the SkyView screens so that the top edges of the screens are aligned with the top of the audio panel.  The holes need a little more filing since the screens are a pretty tight fit right now, but they’re close.  Once I’m happy with the fit, I can drill the mounting holes which will simultaneously lock in the position of the SkyView screens and radio stack mounting rails.  Everything else will be mounted relative to these items.