Main wheel fairing reinforcement and filling

I reinforced the wheel pant holes we had drilled with a couple layers of fiberglass:

Main wheel fairing reinforcements in place

Main wheel fairing reinforcements after curing

It was then time to fill the gaps between the fairings and the bracket, starting with protecting the brackets with aluminum tape and waxing that:

Right fairing bracket wrapped with aluminum tape for gap filling

Right fairing bracket wrapped with aluminum tape for gap filling

Axle extension wrapped with aluminum tape for gap filling

The first batch gave pretty good results, and only required a bit of sanding with the Dremel to get to a final shape:

Main forward fairing aft gap fill before finishing

Main forward fairing axle gap fill before finishing

Sanded right main forward fairing axle gap fill

Sanded right main forward fairing gap fill

When I tried to do the other side by myself, however, the fairings probably moved around too much as I tried to position them, and that made a big mess, so we had to repeat the process to fill the gaps:

Big resin mess around left aft fairing holes

Big resin mess around forward fairing holes

Fixed and sanded gap fill on right main wheel forward fairing

Fixed and sanded gap fill on left main wheel aft fairing

I also started the leg fairings, by using the templates (I printed additional copies of it) to mark the cut lines, then actually cutting them:

Main leg fairings marked for cutting

They fit nicely in place, but we still need to align them (another slightly annoying step):

Main wheel and leg fairings in place

Main wheel and leg fairings in place

We're also getting ready to do the nose gear fairing, so the wheel and brackets are now in place:

Nose gear with wheel and brackets in place

Time lapse:


Total gear leg and wheel fairing time: 38.7h

Main wheel fairings aligned and drilled

Due to the Beringer wheels having different dimensions from the stock wheels (stock wheels are recessed at the center), the axle extensions from Aircraft Specialty needed trimming (reducing the length by 3/4", then deepening the side hole back to 1" of depth), which was easily done on a lathe, except I didn't have one, so a friend was kind enough to do it for me:

Shortened axle extensions

Trimmed axle extension installed in place

With that, we could finally get the the wheel fairings properly aligned - with lots of measurements, markings on the floor (in case it helps anyone, both ends ended up at just about 110.5cm from the airplane's centerline), and a self-leveling laser to help, and slowly opening up the gear leg hole a bit more, we got it aligned just right, then used used magnets to "sight" the hole location from the inside and drill it #40 (with only one minor mistake, which will later get filled with flox anyway) - we used pin punches and drill bits to keep it in place while drilling the other holes:

Measuring the distance from the aircraft centerline

Self-leveling laser marking the horizontal reference for aligning the fairing

Right wheel fairing aligned just right thanks to the self-leveling laser

Right wheel fairing "temporarily attached" with the drill bit itself and a pin punch

I then opened up the holes to #36/#27 and tapped the bracket for screws:

Right wheel fairing screwed in place

Rinse, repeat it all for the left side:

Left wheel fairing in place

We measured and marked the required gaps around the gear legs and the tires, then trimmed the fairings to those markings:

Marking the required gap around the tire is slightly awkward

I then started the nose wheel fairing, with a similar process to make the parts fit together:

Nose gear forward fairing attachment holes marked and drilled

Nose gear fairing center markings

As a last step that I could do before the nose wheel is on (which requires jacking the aircraft a bit higher) was to open up the large hole that the nose gear leg goes through:

Nose gear forward fairing with gear leg hole cut out

Next we need to start filling/reinforcing the inside of the main fairings, and then also align and match-drilled the nose gear fairing.

Time lapse:


Total gear leg and wheel fairing time: 26.0h

Panel wiring harness complete

Continuing the main wiring harness surgery, I remapped the fuse block wires from what SteinAir originally did - eliminating a few more wires from the conduit to the overhead console (e.g. no reason to have separate wires and fuses for the front and rear overhead lights), and adding the Spartan3 AFR sensor (which I kept on the main bus instead of the Bus Manager on purpose - I only want it to start heating the sensor after the engine is running, and it has a mode where it'll start 3 minutes after being powered on, so on my start checklist, turning on the main bus is the last step before hitting the starter (and before that the avionics are powered by the IBBS, while the EFII system is completely independent of the main bus):

Changes to be made to the fuse block wiring

Updated fuse block and wiring

For connecting the door relays, I got connectors that attach together, and wired them directly from the fuse block:

Door indicator relays attached to sockets

Door indicator relay sockets with power wiring

I then chose the position to attach those relays (nutplates will be added later), and laced those wires:

Fuse block, door indicator relays and GAD29 in place, with wire bundle tidied up

I protected the main bus bar (that connects the tailcone solenoids) against accidental contact with heatshrink:

Tailcone bus bar with heat shrink protecting non-contact areas

I also rewired the EDS-4IP's distributors per MH's recommendation, which means a single power wire pair for all of them (the controller's pins are connected together anyway, and all my distributors are near one another, so that saves me a bunch of wiring up to the overhead console:

Updated Mountain High EDS-4IP connection diagram

For the Spartan 3 air-fuel ratio sensor, I soldered a Molex Ultra-Fit (172287-2308) connector to the board - the connector is only 8 pins (vs the original 10), but the last 2 pins are not used anyway. This will be much more secure than the original screw-in connector, and as mentioned on the last post I'll 3D print a custom case for it:

Spartan 3 AFR sensor with Molex connector soldered on

I then moved the main harness back onto the panel to figure out its attachment - with Adel clamps on the VP-X screw holes on the left, and figured out the right places to add holes/nutplates for Adel clamps on the right:

Tidied-up GTN/GNX wire bundle, ready for re-lacing

Right-side main wire harness held in place with Adel clamps

I attached and wired the essential bus bar and fuel pump relay to the back of the panel substrate:

Essential bus bar connected to circuit breakers and fuel pump relay

I then decided I didn't like this :) The wires going all the way down to the relay felt weird, so I swapped the relay and the bus bar locations, whch looked much cleaner:

Essential bus bar connected to circuit breakers and fuel pump relay, but swapped positions

Finally, I re-laced the main wire harness, which gave it a nice and secure finish (I'll also add some edge grommet to the subpanel hole to protect it):

Re-laced GTN/GNX wire bundle going through subpanel (still without edge grommet)

Re-laced GTN/GNX wire bundle

Re-laced main wire harness

The only part of the panel wiring that I'm leaving for later are the EFII wiring (since I don't have the LRUs yet) and the breakout connectors. There's also of course the rest of the wiring that's not behind the panel (back to the tailcone, in the tunnel, and firewall forward).

Time lapse:


Total avionics rivets: 59
Total avionics time: 76.3h

Panel assembly and more wiring surgery


I riveted the VP-X attachment extension, then attached the essential bus bar to the panel substrate, right next to where the circuit breakers sit:

Essential bus bar attached to panel substrate

Continuing with the wire harness surgery, I was worried about having enough space for all the wires and cables in the conduit to the overhead console. The Mountain High EDS-4IP (oxygen system) had four 4-wire shielded cables which was kinda bulky, but 2 wires in each of those were power and ground, so I checked in with them and they told me it's fine to run a single power and ground unshielded pair to all of them (since they'll be in the same general area), so I took all of those out and will replace them with four 2-wire shielded cables which seems a lot easier to fit. On the cable to the tank valve, SteinAir also hadn't run a wire for the regulator pressure sensor (controller pin 20 to valve pin 8), so I reused one of the 4-wire cables to do that (replacing the previous 3-wire they used for the tank valve):

Reworking the Mountain High tank valve and distributor wires

I wired the battery fault LEDs, by adding Molex SL connectors (so they can be easily removed from the panel, and splicing the main harness wire that went from the GEA24 to the batteries to connect those:

Battery fault LEDs with Molex SL connectors attached

Battery fault wires attached in place

Last but not least, of the 4 wire bundles that connect to the GEA24, 3 (J241, J243, J244) have some or all wires that need to go into the main harness, so I bundled them all into a single harness and routed the wires to the right exit point, while also adding the EFII connections (RPM, fuel flow, fuel pressure, AFR) and removing an unnecessary Molex connector between the bundles:

GEA24 bundle including most of the J243 and J244 connector wires

(J242 only connects to the engine sensors, so I kept that one separate, and also left other wires that will go into the engine compartment outside the bundle)

Next I need to rework the fuse block wires, and then I can finally mount the bundle into the panel again, this time figuring out attachment points and re-doing the lacing (though there are still a few details/wires to figure out, like what I'll do about yaw trim). I can also probably start running the side wire bundles in the airplane (and adjusting/trimming their sleeving since they'll be mostly inside conduits).

Time lapse:


Total avionics rivets: 59
Total avionics time: 55.5h

Wire bundle surgery, power wires and LRU nutplates

Lots of wiring harness surgery...I kinda wish I hadn't paid Stein for hand lacing since I'm having to remove/redo so much of it...

To re-consolidate the VP-X wire bundles (move all wires that should go into the main bundle into it, and move all the wingtip wires out the side the same way), I had to de-pin the Molex 150L connector, which was quite annoying to do, at least with the pin that Stein provided:

Removing VP-X connector pin using SteinAir-provided pin tool

I then got the official Molex tool, and unsurprisingly, it easily removed the remaining pins - the tip was just slightly rounder than the one from Stein, which did the trick:

Molex MX150L pin removal tools - SteinAir-provided (white) and Molex official (black)

I also moved the stick grip and flap wires into the tunnel bundle for simplicity:

Tunnel wire bundle

(Also, did you know that Spruce sells heat shrink by the 4ft piece, and not by the foot? Guess who didn't realize it when ordering and will now have a ton of leftover heat shrink? 😄)

For the EFII's AFR sensor, I got the Spartan 3 which seems to be good in terms of firmware and sensor, but I wasn't happy with the connector they use for power and data (screwed-in wires, specifically a OSTTE100104) so I chose a Molex connector with the same pitch but with a latch (172287-2308), and redesigned the case to fit it:

Spartan 3 AFR controller in original box, without original connector (left) and replacement connector (right)

AFR box model with connector and board

Center section of the AFR box

I also tried a right-angle connector, but ultimately didn't see a reason to use that:

Right-angle connector version of the AFR box

I'll eventually 3D print that (probably PC+CF filament?).

I received my main battery cables from Aircraft Specialty, and they actually fit as intended (caveat that they use white wires and only color the heatshrink, but the terminations are really high quality which makes it worth it):

Box of wires from Aircraft Specialty

(mock) battery, contactors and external power port with wires near their intended spots

(mock) battery and contactors with wires near their intended spots

After a batch of primer, I riveted all the LRU attachment nutplates, to the tailcone avionics tray and the subpanel:

Tailcone avionics tray with LRU attachment nutplates

Subpanel parts with LRU attachment nutplates

I also riveted the VP-X attachment parts:

Riveted VP-X attachment hinge and bracket with nutplates

Coming up next: more wiring work, need to check/complete the GEA24 discrete inputs, rework the fuse block wires (I consolidated a few that go up to the overhead console, added the AFR sensor, etc.), connecting the trim position and ELT wires to the side breakpoint connectors, and simplify a lot of the O2 wiring (MH told me it's OK to run a single power wire to all the overhead distributors, so I'll do that instead of having 4 shielded sets).

Time lapse:


Total avionics rivets: 49
Total avionics time: 45.2h