Tonight I made a couple more access panels for the wings. I had originally made enough, but I had used one to mount a Dynon pitot heat regulator, which involved drilling and dimpling 4 holes in the panel.
I then added the nut plates to the bottom outboard skin around the access panel openings.
I also countersunk the aileron attach bracket, where the pushrod attaches to the aileron. The pushrod is attached via an AN509-10 countersunk bolt.
Access plates ready to be primedAfter installing the nut plates around the access holesIn the bottom center of the picture is the countersunk hole
Tonight I finished riveting the bottom wing skin. Overall, it all went very smoothly. There are a couple of over driven rivets in there, but nothing that I felt worth removing and re-doing.
Because it’s not possible to see the ship head or bucking bar when setting the rivet, I used a couple of spacers (small blocks of wood taped to the bucking bar) to help brace against nearby rib or spar flanges to help align the bucking bar. It helps to be ambidextrous with the rivet gun, and to have a long reach.
The finished bottom wing skin. The pile of colored rags were used as padding on top of the wing spar, in case I dropped the bucking bar.
The last two nights I’ve continued riveting the bottom, outboard, left wing skin. Nothing to report, other than a minor issue when I realized the j-channel (short) that was installed by the quickbuilders was not match drilled. This makes sense, because it probably needs to be match drilled through the skin and j-channel. The annoying thing is that Vans doesn’t mention match drilling the j-channel at all in the instructions, so it’s easy to miss this step. Anyway, because I already had the skin half riveted on by the time I realized these holes were not there, I was limited in options, particularly when I comes to dimpling. I match drilled the holes, reamed them to #40, then used my pop rivet dimpler to dimple through the skin. This resulted in just enough of a dimple on the j-channel.
After the initial sessions, I had riveted across the aft spa, and a couple of rivets down each ribAlmost to the j-channel (the horizontal row of rivet holes in the middle of the skin)
Last night and tonight I got started riveting the bottom skin onto the left wing. With the quick build wings, the inner skins are already riveted, as are the top and leading edge skins, so this one outboard skin is the only one that needs attaching. I had previously match drilled the j-channel, so I could jump right into riveting.
I started by clecoing the skin on and carefully checking the clearance with the leading edge skins. I’ve found that there’s a tiny amount of sag in the wings, which is corrected when the ribs are all aligned and clecoed to the skin. Getting the skin on, and then getting the ribs all straightened out by clecoing everything allows for some checking of clearances. I found that there’s outboard 18 inches of the bottom skin needed about 1/32 of material to be removed, so the skins can butt up to each other with no overlap.
Once I had the skin trimmed and rechecked, I got started riveting. It’s a bit of a stretch by yourself, but totally doable. I made sure to put plenty of padding down on the spar in case I dropped the bucking bar.
After two sessions (last night and tonight), I’m about 1/4 of the way through the riveting. I’m hoping I can knock this out within a week, it just depends on how much time I can spend in the garage.
Just about to get started rivetingThe yellow tape helps hold the skin away from the ribs and spar to help access
Tonight I finalized the pitot wiring. I have a separate connector at the wing root for pitot heat. Since I had previously planned for a regulated pitot tube, I had three wires run to the pitot tube. With the unregulated model, I don’t need to use the third wire, so I’m leaving it in place as another spare wire.
I unpinned the pitot heat wire from the standard Vans wiring harness and connected it to the separate Pitot heat molex connector, then ran another ground wire from the pitot heat molex connector to the ground point on the fuselage. At the pitot tube end, I installed pins on the wires from the pitot tube, but held off on installing them into the molex connector. I need to wait until I have installed the mast, and the pitot tube, routing the wires through the mast in the process. If I install the connector now, there won’t be enough room to fit the molex connector through the mast.
Anyway, it was a fairly quick job to get this all finalized.
The four connectors at the wing root are a little overkill. The two on the left are standard Vans wiring harness. The third from left is the pitot heat connector, and the right hand connector connects spare wiring that runs to the wingtip.This is where the pitot mast will attach. The wiring will plug into the molex connector on the right. The Pitot and AOA lines will attach to the white and blue lines respectively.Feeling pretty good about progress so far.I went ahead and retrieved the bottom wing skin from storage. This has some history, having been partially attached to a different left wing earlier in the build. I was very careful when I removed it from the original wing, and it’s in great shape.
Tonight I bent, flared, and fit the Garmin pitot tube. Doing this for the second time (first time was Dynon) was a lot faster, and easier because I could use the Dynon tube bends as a reference.
There are some interesting differences in the Dynon and Garmin pitot tubes. The Dynon is noticeably longer. The tubes are marked “pitot” and “AOA” on the Dynon, but unmarked on the Garmin. I added some heatshrink labels to identify the tubes, after gently blowing through them to confirm which was which.
I’m installing the unregulated Garmin pitot tube, so there’s no controller box needed. The switch on the panel will turn it on, and it’ll stay on until switched off on the panel. This is how it works on most aircraft, and since I’ll hardly ever use it, simple seems best.
Working on the pitot tubeTubes need to be bent to allow clearance from the aileron pushrod, without contacting the spar Some thought was required to remember to put the b-nuts on at the right time: after the tube is bent, before the tubes are flared. The messy touchup paint job on the pitot mast. I could have done a better job, but I’ll worry about it later.
I’ve decided to switch back to working on the wings, so I can finish them up and then move them to a hangar. That should give me a little more room in the garage to finish the tail fairing.
It has been a couple of years since I worked on the wings, and a bit of a saga. My original quick build wings were impacted by the Vans primer problem, and I sent them back. But I had already made up the bottom skin for the left wing, including a cutout and holes for pitot mast and reinforcing. I had started riveting the skin on when the vans primer problem was announced. I carefully removed the rivets, and saved the skin. Then I decided to switch from Dynon to Garmin, which meant a new pitot tube. Unfortunately the hole pattern is slightly different and the screws are different sizes between the two. Since the Gretz pitot mast I have is no longer available for sale, I wanted to keep the original mast and bottom skin, and find a way to make it work.
On closer inspection, the holes are in almost exactly the same place. The different is the screw diameter, with Dynon using something like a 3/16 and Garmin a smaller #6-32 screw.
Because the screws carry a sheer load, and because there is plenty of material supporting the screw, I decided to use something JB Weld to fill the void under the screw heads. I coated the pitot tube mount and the screws in boe-lube and then set them into the filler. In the morning the filler had dried, and I backed the screws out, then cleaned up the filler with a file and some sand paper. I painted the filled area with some powder-coat touch up paint. The finish looks rough, but I’ll worry about it when I paint the plane, eventually.
Tonight I switched out the Dynon roll servo and replaced it with a Garmin unit. Originally I had thought I would install a Dynon panel and system, but decided to switch to Garmin. Replacing the roll servo was a job that had been on the to-do list for a long time.
Aside from a couple of different bits of hardware, the units use the same parts. It was fairly easy to do, after finding the right way to get tools on nuts and bolts in the confined space.
The two servos side by side. Dynon on the left, Garmin on the right.The countersunk bolt head has about 1/8 clearance from the baseplate. If this bolt backed off and jammed against the servo, the controls would jam.Pushrod arm installed. The pushrod is the same for both Dynon and GarminInstalled and torquedEverything installed and torquedView looking down (forward) from inside the wing. The wiring run is so short I decided it didn’t need any bracing.
With the aircraft outside, we took the opportunity to test the lights and other systems. I tested the landing lights, taxi lights, navigation lights, strobe lights, wig-wag function, magnetometer, satellite reception, canopy fans, canopy flood light, comm radios, and GPS receivers.
There were some issues with the lighting which I’ll need to investigate and fix: one row of red nav LED lights were intermittent, the wing tip strobe lights were weak, and the right side, leading-edge, landing lights were in-op.
Aside from that, everything else worked as expected.
In order to test everything I made a wiring harness that was 7 feet long and allowed me to connect the wing lighting from both wings while they remained in the wing cradle. I positioned a couple of workbenches behind the fuselage so I could plug in the tail light, and the wingtip lights. It’s possible the extra 7 feet of wiring had an adverse effect on the lighting voltage, contributing to some of the problems, but I didn’t attempt to troubleshoot.
G750 receiving GPS signalGPS signal from the GA-35 antennaMagnetometer connected, but not yet calibrated. Note, all lights are on, and current draw is 16.5AThe wing connection setupI had to drop the left wing down out of the cradle to connect the wiring Nav light test. The intermittent LEDs are on the bottom left of this image, which is actually the top side (the top is upside down here)Right wing nav lights looking good
Tonight I started on the task of running pitot static lines from the wing attach point to the panel. There are two lines that run in from the wing, a pitot line and an AOA line. They will t-off behind the panel with one line going into the back of the AHARS, which is mounted to the back of the PFD, and the other lines running to the G5 backup instrument.
This ribs already have one set of holes running through the seat ribs that is just the right soze for one line. There are other holes too, the outboard ribs have two additional holes for installing gear leg bolts for tri-gear models. The inboard ribs have tooling holes. I enlarged one of three tooling holes on each of three two ribs under the pilot seat, and installed snap bushings. Conveniently, the spar already has two holes I can use to run these lines forward of the spar and into the center tunnel.
I’m planning to install quick connect fittings somewhere under the pilot seat, probably on one of the inboard ribs. I ordered a few fittings from Stein Air and will tackle that when they arrive.
Shavings visible for enlarging the top hole. The angle of the camera makes it look like these holes are closely spaced, but there’s over an inch edge distance.After using the step drill to enlarge one of the tooling holes. I actually drilled a new hole to offset the center of the enlarged hole, ensuring enough clearance