Assembly Tasks

Posted on by Neal

This week I made multiple trips to the hangar to work on various tasks.

Wing attach bolts

I finally torqued the wing attach bolts. The night before, I tested out my torque wrenches to ensure they were reading correctly, and they were both very close. I used a vice to hold the wrench, and then secured a weight over the arm and measured the distance from the fulcrum. For weight I used a 1 Gallon plastic jug filled with carefully measured amounts of water. The nuts were easy to torque, I only found one where it took a second to figure out how to torque it. I ended up using a socket extension that allowed some movement, so I could torque the nut without fear of bending small bits of aluminum that were close by.

Pitot tube:

I finalized the wiring and install of the pitot tube. I used butt splices to connect the pitot heat wiring, replacing the original molex connector. In the process I included a service loop to help with any future maintenance.

I also trimmed the pitot and AOA pneumatic lines at the wing root, inserting them both into the connectors under the seat. I still need to test the system for leaks, and to verify I didn’t switch Pitot and AOA at any point in the system.

Strobe lights:

I did some troubleshooting on an issue with the wing tip strobe lighting. Both sets of strobes are flashing, but weakly. There is only 6.6V at the wingtip, so I’m losing half the voltage somewhere in the system. I tried the easy tasks such as unplugging and reconnecting connectors, but no luck.

VOR Antenna

I completed the VOR antenna wiring, and was happy to tune in a nearby VOR and see a positive ID and a needle on the CDI. The reception seemed good, even though the antenna isn’t well grounded (I don’t have all the screws in the wingtip, and they provide the ground path). The job was quite simple, I just needed to cut the cable to length and install a BNC connector, then plug it into the fitting I had previously installed under the passenger seat. I added a service loop, for ease of maintenance. At the right wingtip I connected the ring terminals to the antenna and torqued them up. I also tidied up the wing tip wiring and then secured the wingtip fairing. I then fired up the instrument panel, turned in the Julian VOR and was happy to see the reception, even on the ground in a metal hangar at 20 miles, and without a properly grounded antenna.

The main spar wing attach bolts, final torqued
One of the aft wing attach bolts
Signs of life from the VOR antenna. The Nav radio is tuned to 113.75, and the green line on the left hand screen (PFD) is pointing to the VOR station
The VOR antenna connection under the passenger seat
Right wingtip wiring. With the wingtip off, I found I could rotate it and set it on its aft edge, balanced against the wing. This made working on the wiring much easier.
Service loop for the pitot heater wiring. Insulated butt splices are visible here and would be the recommended place to disconnect the pitot wiring for any maintenance
Another angle of the pitot tube install. Note, the pushrod is disconnected to allow more room to access the pitot tube wiring.

Safety wiring panel connectors

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Over the last few evenings I have spent time inspecting the wiring behind the panel. I made a few adjustments to ease bend radii, address some potential chafing, and finally to safety wire the connectors into the various components behind the panel. This required removing a few plugs for access, and then making a best effort to safety wire the connectors screws. Given limited access, it’s not my best safety wiring work, but it’ll get the job done.

Some of the plugs that needed safety wiring. In this case I’ve removed a few plugs to gain access to these.

Pitot Static Check

Posted on by Neal

Tonight I checked another item off the to-do list by testing the pitot and static lines for leaks. Good news – both the pitot and static lines were leak-free. I wasn’t able to test the AOA lines, but will have to do that sometime down the road.

I started with the pitot line. By removing the pilot seat floor panel, I could access the ports where the pitot and AOA lines will connect once the wings are attached. I used a piece of flexible tube, and attached one end to the Pitot connector. I gently blew into the other end until the airspeed registered, and then folded over the tube and held it for a minute. The airspeed indications on the G3X and the G5 held steady for a minute, which met the standard.

Flexible tube plugged into the Pitot connector under the pilot’s seat
Airspeed indication holding steady at 146 knots

For the static line test, I ended up taping over the static ports, then disconnecting the G3X static line where it joins a t-connector. Using the flexible tube again, except this time gently sucking air, I was able to demonstrate steady altitude on the G5 for over a minute. I guess there’s a small chance of a leak between the t-connector and the G3X, but at least I know the G5 has no leaks.

Altitude holding steady at 5000 feet
Squeezing the tube sealed the end well enough to conduct the test

Pitot Static

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Tonight I installed t-connectors on the Pitot and Static pneumatic lines, and routed all lines to their respective ports on the G5 and ADAHRS unit.

With that done, the panel wiring is complete!

Well almost complete, I still need to:

– safety wire some more connectors

– throughly inspect all wiring and fix all potential chafe points

– route the firewall-forward wires up to and through the firewall

– upgrade the battery-vertical power wire from #8 to #6 AWG

The Pitot (Blue tubing), Static (Red and clear tubing), and AOA (white tubing) plumbed into the G5 (left) and ADAHRS (right).
Thinks looking much tidier under the panel now

Pitot Static

Posted on by Neal

Tonight I installed a couple of adel clamps to hold the pitot static lines, keeping them clear of the sharp edges they pass near under the panel. The routing is a little weird because I don’t want to put too sharp of a bend in the tubes. The tubes come up out of the wiring channel, pass over the wiring frame I built, come out the bottom of the forward side of the sub panel, then up through a gap between the panel and sub panel. I plan to install t-connectors on the top of the shelf behind the PFD, sending air to both the G5 and the ADAHRS unit mounted on the back of the PFD..

I then mixed up some epoxy resin and glued some zip tie holders onto the shelf.

Two adel clamps holding the pneumatic pitot, static, and AOA tubes where they pass under the sub panel and back up to the shelf behind the top of the panel.
The pitot static lines emerging onto the shelf. Note the black zip tie holders glued to the shelf to support the t-connectors

Panel Wiring

Posted on by Neal

Over the last week I’ve been chipping away at the panel wiring in the evenings. It’s hard to measure progress sometimes because I’ve been spending a lot of time on very small tasks, and/or doing something one way only to do it again a different way.

The main accomplishment, however, has been installing the wiring channel that connects the center tunnel to the sub panel. This is a lightweight frame that allows the wiring and pitot static lines to neatly fit inside, keeping all the wiring out of sight and out of the way of the occupants. This was not as easy to install as I hoped. The problem is access to the rivets that attach the frame to the sub panel. On one side there is an existing frame, and on the other side are the many bundles of wiring. I ended up drilling out the rivets and removing the frame that was blocking my access. Then I set pop rivets in place, then reinstalled the frame I had removed.

Once I had that channel in place, I installed the cover and checked for clearance on all sides. I found the connector for the standby battery was just touching the connector for the CO detector. The standby battery is installed on a panel above the fuel pump, just forward of this wiring channel. The CO detector is installed on the backside of the cover that sits on the wiring channel.

To solve the issue I relocated the CO detector mount, moving it sideways and up. This required drilling out some rivets and making some new holes, but it was no big deal. It’s now in a position where the two connectors and their wiring runs are not contacting each other.

With all that work done, the whole area is looking much cleaner and tidier.

The wiring channel painted black and clecoed into position. Note the top of the channel fits in a narrow gap between the sub panel and another aluminum bracket, just visible at the top of this picture.
Test fitting the wiring channel cover. At this point I’ve already identified the conflict between the two connectors, drilled out rivets, and I’m testing a new location for the CO mount.
View of the forward side of the wiring channel, looking aft. The two arrows indicate the connector locations, and you can see the gap that now exists.
The wiring frame connecting center tunnel to the sub panel, pop riveted in position after an aluminum bracket has been removed to allow access. Note the Note the rectangular standby battery behind the frame.

Panel Wiring

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Over the course of the last week, I’ve spent time installing the wiring frame between the sub panel and firewall, and the slowly working to zip tie and secure the various wiring bundles onto the frame. Lots of time spent on my back with my head under the panel making slow but steady progress.

There has been plenty of trial and error as I’ve tried to secure the bundles, and simultaneously untangle things. Most the the antenna cables ended up unplugged, re-routed, and then plugged back in again. I experimented with gluing zip tie holders onto the sub panel, but ended up removing most of those, as I found it better to use clamps and/or to secure the zip tie around or through a piece of aluminum. The zip ties are good for keeping the bundles together.

It’s finally starting to look a bit more tidy now.

Panel wiring

Posted on by Neal

Tonight I installed an adel clamp to hold the wiring bundles on the right side of the sub panel. I also worked on safety wiring the various connectors on that same side of the panel. The safety wiring is going to be a challenge for some of the connectors behind the MFD, but I’ll figure something out I’m sure.

Some of the safety wiring visible on a couple of the connectors. I had to redo some of these because I wasn’t happy with the original attempt
Adel clamp to keep the wiring bundle together, keep it away from sharp edges, and provide some strain relief on the connectors

Panel Wiring

Posted on by Neal

The last couple of evening I’ve been using trial and error to work out the right structure to support the wiring behind the sub panel.

One of the changes I’ve made is to rivet together two pieces of channel to reduce the sharp edges.

I also installed an adel clamp bracket on the right side of the subpanel to hold several wiring bundles.

Getting ready to rivet the two halves of the cross beam

Panel Wiring

Posted on by Neal

Tonight I started on the daunting task of trying to tidy up the wiring under and behind the panel. It’s a giant, heavy, ball of spaghetti right now, and I’m not sure if I have enough length to position things where I need them.

I decided I needed some kind of frame behind the subpanel to support the main wiring harness. Using some spare channel, I mocked up a frame and started trying to figure out a solution. I eventually settled on two channels running from the sub panel to the firewall, and a cross beam made from another length of channel. I should be able to rivet the fore/aft channels on the sub-panel end, but not sure I’ll be able to get rivets in on the firewall end.

The scary mess
The basic structure I intend to install