Firewall Interior Heatshield/Upholstery

When we purchased our kit, we also elected to purchase the "premium upholstery" option.  This included a piece that is placed on the interior firewall being attached by velcro strips.  Now that we've just about completed our firewall attachments, it was time to see how this piece fit.  It is actually nicely done, including an insulation layer that should help with both engine heat and a sound deadening layer.  Problem was that it was too tall and interfered with our wiring and heater core installation.  After talking several measurements the  part was cut down to fit.  Had to break out the sewing machine to hem the edges that were now exposed.  Two areas on each side had to be cutout to accommodate the rudder return spring attach points.  The velcro attach points had to be re-done as well.  Four (4) new pieces of velcro was sewn on to the small part.

Hours: 4

Newly Resized Firewall Upholstry Piece

Velcro Strips, the two diagonal we old attach points 

Checking for fitment in the cockpit.

Battery vent, brakes, wiring

The battery vent hose routing was completed.  This directs any unwanted gases from the battery out the airplane in the unlikely event of a (lithium) battery failure.

Battery vent tubing installed

More wiring bundling and cleanup was completed.  We are pretty much done with the wiring now until we get the chance to put the wings back on, in which case we will wire up the navigation lights and magnetometer.

Wire bundling behind the instrument panel

Wires bundled and routed behind pedals

Wire bundling in back of airplane

We ran into a few issues with the brakes.  When attempting to bleed the brakes, we found some problems.  One is that the parking brake valve was reversed.  This was corrected.  But then we realized an issue that we should have found sooner.  Our brakes have 2 master cylinders, one attached to the backside of each of the pilot's pedals.  The top of the master cylinders need to be at the highest point in the hydraulic system because they have an integrated resevoir for the brake system.  Unfortunately this was not the case because our parking brake valve sits much higher on the firewall.  We figured there are 2 ways to fix this.  Either change the brake system to add an auxiliary resevoir at a higher point (also requires us to change 2 cylinders), or just remove the parking brake.  To keep the parking brake, we figured we'd have to spend another $500 or so, and add more weight.  This didn't seem worth it since the parking brake is not required, so we decided to remove the parking brake.  Kind of a pity since so much time was spent on this, but we both think this is the best decision in the end.  We can always add it back later if we change our minds.

Michael bleeding the brakes

Lastly,  four nutserts were installed for the fuel on/off switch.  This will allow us to install the plate with simple 8-32 screws instead of the sheetmetal screws that were part of the original plans.  Hours: 20

Firewall passthru, wiring cleanup, hoses, labels

Two firewall wiring pass-thru plates were fabricated from 1/8" titanium plate. A ledge was milled into each piece so that they have some overlap where they meet in the center.  There are 3 holes, two for the large Rotax engine harness HIC cables, and one for other sensor wires and the alternator cable that pass through the firewall. Silicone grommets were used to seal around the cables, and the high temp sealant (Permatex 27036) was also used to seal around the titanium pieces.

Titanium pass-through plates

Our EarthX lithium battery has two vent ports that need to be connected to hoses that can exhaust fumes outside the cabin.  This provides a path for unwanted gases in the unlikely event of a battery failure.  A vent outlet was installed on the bottom of the fuselage.  Teflon tubing will be used to make the connections. Per the manufacturer, nylon fittings can be used if more than 2' from the battery, and brass fittings are needed for closer connections. 

Vent outlet, bottom of baggage compartment

Vent opening, bottom of fuselage

We also ran one additional wire from the battery to the front to accommodate a line from the EarthX lithium battery that provides an indication of a battery fault.  

Additional work is being done to organize, bundle, and clean-up the wiring.  Still quite a bit of work to go here, but we are making progress.

Wire bundling underway, back of fuselage

Wire organization/bundling underway

Rerouting of a coolant hose was completed to provide more clearance, and Adel clamps were also installed to help hold it in place at the Rotax ring mount.  Still need to attach some fire-sleeve material at locations near the exhaust, but at least the routing is completed.

Lower coolant hose rerouted

Panel switch labels were also reprinted to reflect the current switch locations and functions. Hours: 24

Panel switch labels updated

Antennas, wiring, radiator hose, misc

The Garmin GPS was installed in the back of the plane, along with the Garmin Transponder.  These are installed along the side of the fuselage, just behind the baggage compartment.

Garmin GPS mounted in bracket next to transponder

An aluminum ground plane was installed for the GPS antenna; glued to the fabric aft of the turtledeck.  We were originally going to put the GPS antenna towards the back of the turtledeck, but determined that there would not be enough separation between the COM antenna and GPS antenna if we did that. so another small aluminum ground plane was glued to the fabric further back after first attaching a fabric backer "doily" for abrasion resistance.  The GPS antenna was then installed with 4 screws that went into nut plates that were attached to the aluminum ground plane.

Small ground plane for GPS antenna

GPS antenna installed on top of fuselage

We are in the process of modifying the routing of the coolant hoses that run from the pump to the radiator.  This radiator hose was routed between the Rotax ring mount and the Just aircraft engine mount, without a lot of clearance.  We were concerned that movement of the engine on the vibration isolation pads (shock mounts) could cause wearing on the side of the hose.  For this reason, we will be shifting it up to give more clearance.  Not a trivial task because we have to remove and remount an aluminum elbow that is screwed into the water pump to change the angle of exit first.  

Original radiator hose routing

All the avionics are now wired up, so we started to do a little cleanup of the wiring, too.  Some wires were bundled with spiral-wrap covering which does a nice job of bundling them together.  We have a lot more bundling to do, but at least we started this part of the job.  Hours: 25

Some wires with protective spiral wrap covering