Assembly Tasks

Posted on by Neal

This week I’ve continued with various assembly tasks.

Lighting:

I resolved the issue with the strobe lights, finding I had mis-pinned a molex connector on the wingtip. Once I corrected the pins, everything worked just fine. It took longer than I care to admit to troubleshoot and find the problem. I learned that it’s useful to start by validating assumptions around where your wires are going by measuring impedance and verifying there is a good electrical connection. Then start measuring voltage drop, once you know your wires are going where you thought they were going.

Comparing this picture to the diagram below, you can see the difference in the pinout. This is actually how I left the connector. Previously the female molex connector actually had the correct pins, but the male was incorrect. Rather than switching the male pins, I just changed the female.
How it’s supposed to be wired. I had the right hand side of this correct, and the left hand side incorrect. I changed the right hand side to match the left .
Lights are all working as expected now.

Aileron Attach:

With help from a saw horse with adjustable leg height, I was able to quite easily install the ailerons. I used new hardware, except for the bushings, since I’ve had these on and off a few times. I was wondering if the install would be more difficult than when the wings were in the stand, but I found it the same, or maybe slightly easier.

I installed and final torqued the aileron pushrods, verified they were correctly rigged using the templates. The templates allow for the pushrod between the aileron and the bell crank to be correctly sized to establish the correct neutral point. Later in the week I rigged the stick-to-wing root pushrods per chapter 41, and adjusted pushrod length until I had the neutral point on both ailerons aligned with a level stick base. I was then able to test the stick clearance, and found I need to trim more off both sticks to avoid hitting the throttle (pilot side) and mixture (passenger side).

I hung the flaps and connected the pushrods, adjusting them to get both flaps all the way up, then verified they have enough clearance from the fuselage.

I also secured the wiring for the magnetometer. I had installed this a couple of years ago but hadn’t finalized the wiring. I had plenty of length so I created a large service loop and secured it out of the way of the pushrod.

Flap pushrods
Calibrating the pushrods took an iterative approach but I eventually got it
Wing tip template helps keep the aileron neutral
Flaps on and configured
Getting the washes onto the bolt that secured the pushrod at the stick base was a challenge. Note, this picture was taken before I torqued up the nut
Passenger side stick interference
Pilot side stick interference

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.

Wing Tip

Posted on by Neal

Last night I fitted the left wing tip’s rib. This involved locating some holes on the rib and on the fiberglass, so that the web of the rib is flush with the edge of the wingtip.

I miscalculated one hole, and needed to fill it once I was done with locating all of the other holes. holes are then countersunk, and the rib deburred and primed.

Tonight I riveted the rib into position. This required the rivet gun, as the flange of the rib is facing inside the wingtip (i.e. outboard). The riveting was quick and easy.

Rib taped into position, and drilling underway.
Once the rib was installed, the wing tip was completed, except for trimming the rear edge. I installed it and marked the line where it will need to be sanded back

Wing tip nut plates

Posted on by Neal

Tonight I installed the wingtip nutplates on the left wing. I had to order a few extra from aircraft spruce the other day, because I was 5 short of the number I needed.

I found one nut plate where the holes weren’t quite aligned, so I filled one of the holes and will re-drill, countersink, and rivet the nutplate on tomorrow. Otherwise I finished the task.

Clecoed nutplates. The one in the foreground has one hole filled to fix a misalignment problem
Nutplates riveted on both sides
Installing the wingtip and measuring the aft edge (where the arrow is pointing). The aft edge needs to be sanded down until it’s flush with the aileron trailing edge.