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 pushrodsCalibrating the pushrods took an iterative approach but I eventually got itWing tip template helps keep the aileron neutralFlaps on and configuredGetting 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 nutPassenger side stick interferencePilot side stick interference
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 torquedOne 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 seatRight 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.
Over the course of a couple of evenings this week I checked out the lights and installed the pitot tube, checking the heater function. I’m trying to fully test the electrical system so I can start troubleshooting and addressing any issues.
The pitot tube installation went mostly according to plan. The Vans plans include a simple, unheated pitot tube, and a lot of builders opt for an upgraded pitot tube with AOA and heat, as I have done with the Garmin pitot tube. One of the considerations for the builder is how to bend the pitot and AOA aluminum tubes coming out of the top of the pitot unit to avoid interference with the aileron push tube. My bends were good, and no changes were needed. Installing the 90 degree aluminum fluid fittings was a bit challenging as access is somewhat limited. I was able to torque them sufficiently so hopefully they won’t leak.
The pitot mast and tube during installation. You can see the end of the pushrod emerging from the darkness directly above the pitot mastA blurry picture of the aluminum pitot and AOA tubes bending around the pushrod and connecting to the flexible tubes via 90 degree fluid fittingsI had chatGPT clear up my blurry photo above. Not too bad, although it’s added some details that aren’t in the original
The wiring was where I ran into a problem. I had previously set everything up, and all I needed to do was insert the crimped pins into a molex connector, then plugging it in. Unfortunately, the pins were slightly too large for the molex connector, and in the process of trying to make it work, one of the pins pulled off the wire. I’m going to need to redo the wiring, so I’ll be looking into other options. I may just use butt splices and ditch the molex connector. I was able to rig it temporarily so I could test the heater unit using the panel switch, and everything worked as expected.
The rest of the aircraft lighting mostly worked as expected, although I had a list of squawks to troubleshoot and resolve. The first issue was the FlyLED Combo spotlights on the right wing were not illuminating. This was a lost connection, and fully seating the molex connector resolved the issue.
The second problem was the tail light not working. This turned out to be an inadvertent switching of the wiring polarity, and switching the pins in the tail fixed the issue. I had previously wired up a small molex connector and successfully tested the tail light. What I hadn’t considered at the time was that the wires need to pass through a small hole in the Vertical Stabilizer, and I had to remove the molex connector. Rather than messing with a molex connector (just another possible point of failure), I used d-sub pins and insulated the pins with heat shrink. This is when I had switched the wires and introduced the issue. The biggest pain was the lack of access to wiring. With the tail spring right under the forward end of the tail fairing, the fairing can only be moved about half an inch, and I had to flex the side of the fairing to reach in and grab hold of the service loop and then remedy the issue.
That leaves two lighting issues to troubleshoot, 1. One row of red LED position lights isn’t illuminating and 2. The wing tip strobe lights are very dim.
I reached out to Paul at FlyLED and he has pointed me in the right direction to start troubleshooting to isolate the problem. Hopefully some investigation will identify the issue and I can get these problems resolved.
With the navigation and landing lights on, the lighting is extremely bright.
Next I’ll be testing the trim system, and eventually the magnetos.
I also heard back from Vans about an interference issue I’m seeing between the fuel tank bracket and the fuselage side skin. I’m planning to trim the corner off the bracket, which I hope to do with some careful use of a small cutoff wheel.
The red circle indicates the area where the tank bracket is contacting the fuselage. It’s the same on both sides, so it doesn’t appear to be caused by a wing alignment issue. I plan to trim the corner off the bracket to create some space
Today my friends Jeremiah, Trey, and Sam helped me mount the wings onto the fuselage. Everything went well, and it’s now looking like a real airplane!
I arrived at the hangar early, and spent time preparing for the event. Jeremiah drove down from LA, and within 5 minutes of his arrival, Trey and Sam landed after flying in from Carlsbad. We got started right away, and things went according to plan.
To prepare for the operation, I had laid out all the necessary hardware, plus the lubricants needed, and the tools I planned to use. I chocked the wheels and raised the tail into a level attitude, and set up some sawhorses to support the wing.
We started by lifting the left wing onto the saw horses and fine tuning the height by removing layers of padding. I then applied Boelube and we gently moved the left wing into position. The drift pins went in with some gentle tapping, as did the larger bolts. Then the remaining bolts were driven through, and the job was complete. It was a fun moment of truth to remove the sawhorses and marvel at how simple the attachment was, and how much load the bolts will carry.
We then moved onto the right wing and repeated the process. Generally it was easier the second time, because we had the process down, and knew where to position everything. It took slightly longer to align the right wing, but there were no issues installing everything.
The only potential issue I observed were there tank attach brackets. The aft corner of the bracket is contacting the fuselage side skin. Items the same on both sides, and it could be “as designed”, but I sent an email to Vans to check.
I haven’t final torqued the bolts yet, but this can wait for a day or two, as the bolts are loaded in shear vs tension.
Raising the tail. It ended up even higher than this picture shows.Lining up the left wingLining up the left wingThe 2×4 helped tremendously to tap home the bolts. Not a lot of force needed, just some gentle bit firm tapsThis time on the right wing, Trey applying some pressure to keep the spar web from flexing as the bolt threads pass through.Both wings attached!Amazing to see the airplane almost completely assembled now. Certainly a huge milestone todayThe tank attach bracket. The aft corner of this bracket it touching the fuselage side skin
Over the last week I finished up the tasks needed to mount the tail components. This included removing and modifying the Vertical Stabilizer fairing, connecting the tail wheel, final torque for the rudder attach bolts, and installing the rudder bottom fairing.
I popped the Vertical Stabilizer fairing off, and took it home for modifications. I needed to shave about 1/8th off the back edge, which necessitated adding some layers of filler and glass inside the fairing, to build up the aft edge. Then using a curved sanding block, removing the required amount of material from the back edge. I did all the glassing and sanding at home, then test fit the fairing, made another adjustment, then primed and riveted it back into position.
Then I installed the rudder attach hardware and torqued the nuts on the attach bolts. There’s no easy way to get a torque wrench onto the nuts, so I did the best I could to achieve the right torque.
I hooked up the tail wheel using sash chains and springs, and then adjusted the length of the chains to get about the right amount of tension. I found using zip ties to compress the springs, and to hold the tension on the chain helped to hook everything up.
I then wired up the tail light, and coiled the slack cable into the fairing. This is when I discovered that the rudder bottom fairing can’t be installed with the rudder in final position. After some Vans Airforce research, the advice was to remove the bottom two rudder attach points and swing the rudder sideways and aft to allow the fairing to fit, then reassemble. So at midnight on Saturday I felt like I was starting again, undoing the attach points, taking off one of the sash chains, installing the fairing, then putting it all back together.
Anyway I eventually got it all done and headed home in the early morning hours.
The rudder attach hardware is hard to access Sash chains and springsThe forward edge of the rudder bottom fairing can’t be attached due to tail wheel spring (the white steel tube) interferenceEverything finally in place on the tail
Today I was able to install the Vertical Stabilizer and the rudder. Before I started that task, I spent time filing down the elevator horns stops. That is, the deck angle on the aft end and the deck doubler on the forward end.
The filing was tedious as I was carefully working to get the correct amount of elevator travel. I was able to get the prescribed 25 degrees of down travel, but not the full 30 degrees of up. I’m at 27.5 degrees up, and not comfortable removing any more material from the aft deck angle before hearing back from Vans. From what I can tell, I’ll have to remove a significant amount more to gain the addition 2 degrees. All of the dimensions appear to be correct, so I’m not sure why I’m having an issue.
Update: tech support at Vans concur that it’s not worth any further filing to gain a couple more degrees of up travel. I’m going to leave this as-is.
The VS install is easy, and I’ve done it so many times now, I was able to complete the task quickly. I had to torque the bolt heads on the bottom 3 bolts (vs the nuts) due to no real access for a torque wrench, so I added some additional torque to account for the bolt movement.
I did run into an issue with the rudder, there’s some interference between the forward edge of the rudder counterweight arm and the aft edge of the Vertical Stabilizer fairing. Not sure how I didn’t find that earlier, but I’m hoping some light sanding will resolve the issue.
The rudder can pass through it’s full range of motion, but it’s rubbing and binding between the fairings The area of interference that I’ll need to resolveLooking good with the tail installed
