We also connected the remaining wires to the alternator regulators, and regretted again installing them behind the subpanel due to the gymnastics required to do this:
Alternator regulator with wires connected to it
Alternator regulators with all wires bundled up and connected to them
Lying upside-down to organize and connect the alternator regulator wires
I also finished installing and torquing the engine grounding straps:
Grounding strap secured to both engine and mount
I tested the LED strip position to see if I'd need to cut it to reduce glare (apparently not), and ran the wire through the panel with the tiniest snap bushing I could find, which turned out to be 0.19" OD. The wires will be hidden between the metal and carbon fiber parts of the panel:
Testing LED strip with white light
Testing LED strip with red light
LED strip wires running through the panel and connected to the strip
The Mountain High O2 system has an emergency O2 valve - the valve itself is in the regulator (attached to the tank), but it's pneumatically actuated (supposedly so it works even in a total electrical failure?), so I had to run the tubes for the emergency O2 switch into the panel:
Emergency O2 control tubes connected to the switch
Emergency O2 control tubes running through the panel to the switch
In case you're wondering if I'm fully done with avionics - of course not :) the wiring never ends...
To prevent issues with a hot tunnel, we insulated the forward part of the tunnel with fiberfrax and titanium foil - much like the firewall, except on the inside. This does mean that we're not protected from an engine fire opening a hole in the skin, but during normal operation this should keep the tunnel cool.
Titanium foil + fiberfrax protection for the forward tunnel
We then tightened the fuel hoses to the valve and firewall, in the right position for the fuel pump to be dropped in, while avoiding the heat tee servo:
Fuel hoses attached to firewall fittings
Fuel hoses attached to fuel valve
It was then time to attach the fuel pump, and secure the fuel return hose to it:
I had to figure out where to attach the heat tee control servos so as not to interfere with fuel lines and cables (but still have the right angle and range of motion). This is what I came up with:
Fuel hose around forward heat tee
Servo (roughly) positioned to move the tee's flap without interfering with the fuel hose
Aft heat tee servo (roughly) positioned to move the flap without interfering with the rudder cable
I had the option of mounting the aft servo at the bottom, which would keep it out of the way, but decided that'd be not just harder to install, but harder to service, plus a broken servo attachment at the top means the rudder cable may rub against it (not great but probably doesn't lock the rudder), whereas a loose servo at the bottom could irremediably bind the elevator pushrod. This position also called for a slightly shorter actuator (you can see it's almost fully retracted above with the lever in the far position), so I switched to a 30mm equivalent, and in order to make it easier to run the wire to the servo controller on the center console, I switched it to the right side.
I also terminated the wires to the forward servo, and re-terminated the servos themselves to use Molex SL connectors that have a locking tab.
I replaced the arms of the heat tees with almost-identical ones, except with smaller holes for the servo (#8 instead of #10) and the aft one with a slightly smaller arm. I also made a doubler for where the aft servo bracket will go in order to use a countersunk screw to attach it (but the forward one is too far out of sight for it to matter), and will use the CNC shock mount from ServoCity as a bracket for the servos:
Heat tea servo arms, bracket and doubler
Securing the servos in place was slightly annoying (notably the forward one which is harder to reach), but they ended up in good positions, avoiding the pedals, cables and fuel hoses:
Forward heat tee servo secured in place
Aft heat tee servo secured in place
SCAT tube connecting the aft heat tee to the Aerosport fuel valve bypass
Center spar protective rubber layer where the SCAT tube lies
Forward heat tee SCAT tube secured in place
We also ran the forward SCAT tube from the firewall to the Aerosport fuel valve bypass, and secured it to the tunnel cover (which was a little annoying to do, but we managed it, and it cleared the pedal arms nicely):
Firewall-to-fuel-valve SCAT tube secured to firewall
Attaching the SCAT tube bracket to the tunnel cover
Attaching the SCAT tube bracket to the tunnel cover
Firewall-to-fuel-valve SCAT tube secured in place, well clear of the rudder pedal arms
We then had to calibrate the limits of all the servos so they don't stall - the aft tunnel servo was well within range even at its extremes, but the forward servo needed limiting, which I did by using a borescope to watch the flapper move towards its limit, while adjusting the tiny trim pot on the controller:
Heat tee right position during servo calibration
Heat tee left position during servo calibration
The tailcone servo for the overhead air also needed adjustment, to both the wires holding the arms, and to the controller, and we then installed the duct to the overhead console:
Tailcone overhead air valve connected to the bulkhead flanges
Finally, we riveted the forward NACA vents, with sealant and the metal doubler:
Forward NACA vent riveted in place
Forward NACA vent riveted in place, with metal doubler
With this, the only two things left for ventilation are the tailcone vent-to-valve duct (which we're holding off on installing since that makes it even harder to get into the tailcone), and connecting the forward intakes to the panel.
For grounding the engine (and thus the starter and alternators) I decided to both install the Vans-recommended (OP-37) grounding straps, and one to the firewall grounding block - that gives me redundancy (it's still an electrically-dependent airplane), and has little chance of creating a ground loop. I drilled up the engine mount tabs for AN5 bolts (did I mention drilling hard steel in a hard-to-reach spot is a pain?), removed the powder coat from approximately the contact area of the ground strap terminal, and attached them:
Engine mount hole for grounding
Engine mount hole for grounding, with powder coat removed
Grounding strap between engine and engine mount
Grounding strap between engine and engine mount
Grounding strap between engine and firewall
We also used ProSeal to seal all the antennas - this made a bigger mess than expected and required quite a bit of cleanup to get a smooth fillet (a hint we didn't see or think of in time was to apply masking tape to the antennas to make a clean edge):
Sealed COM, Stormscope and ELT antennas
Sealed GPS antennas
Sealed TAS antenna
Sealed transponder antenna
Sealed GPS antenna before cleanup
Sealed GPS antenna after cleanup
We installed several more ClickBond fasteners, for the forward and tailcone servo wires, the top forward conduit wires (away from the screws that attach the cabin cover), and the remaining overhead console fasteners:
Heat tee servo wires secured to tunnel wall
Tailcone vent servo wires secured to the ceiling
After installing the fuel pump, we ran the remaining wires through the forward tunnel, connecting the GHA15 and the stick grip connectors on both sides:
Tunnel wiring secured around the fuel pump
Stick grip connectors secure in place in the tunnel
Stick grip connector coming out of the tunnel
There's not a lot left to do with avionics (well, at least compared to how much we've done so far) - once the tunnel is fully closed up, the alternator regulators are connected, and I update the firmware on the O2 sensor controller, the main things left will be securing the firewall-forward wiring, installing the overhead console inserts, and actually installing the panel and avionics permanently in place.
