Month: January 2020

I received a shipment of electrical supplies today from steinair.com, which enabled me to finish the left elevator. Instead of using a molex connector, I went with Stein’s recommendation on using dsub pins, and heat shrinking the wires. I picked up some crimping tools and a decent wire stripper, along with the dsub pins and some heat shrink.

I crimped the male and female pins, then slipped on the heat shrink, and pushed the pins together

Then slipped the heat shrink over the pins and used a heat gun to shrink the wrap making a nice tight seal.

Then I installed it in the left elevator, using some Velcro to hold the wires securely inside the elevator.

With that done, I hooked up the trim tab, and then installed the counterweights, putting some thread marker to ensure I can tell if the nuts ever back off.

Here’s the finished product:

Today I attached and safety wired the trim tab to the left elevator, trimmed and applied silicone to one of the trim tab molex connectors, and fitted the counterweights.

The trim tab fits perfectly, and the hinge is snug against the rear spar. I safety wired the hinge pin into place. I ended up redoing the safety wire after I took this picture, getting a tighter fit and a few less turns

Next job was to trim the corners off a molex plug, then seal it with silicone. This will be exposed to moisture, so the sealant is important. I bought some electrical-grade silicone sealant to ensure it doesn’t react with the wiring in any way.

Then it was onto the final step in the elevator plans, attaching the counterweights. I drilled out the holes to #12 using my drill press, then deburred the holes. I marked and trimmed the weights using a hacksaw and emery file. This was easier than I anticipated, and I soon had the weights ready to attach.

Starting with the right elevator, I bolted on the weights, then torqued them to 28 inch pounds. I used some thread marker to ensure I can tell if these ever back off. With that, the right elevator is finished!

Installing the left elevator weights was more challenging. After some trial and error, I realized that there is an alignment issue with the holes on the tip ribs. These holes are 0.03 inches too far apart, which is causing the bolts to splay out, and preventing them from being able to attach the inboard weight. I carefully filed the bottom hole to allow the bolt to pass, but ran out of time to secure the weights.

Today I flush riveted the trailing edge of the right elevator, and then rolled and riveted the leading edge.

I used a new tool, the safety-pin angled squeezer dies from Cleveland tools, and squeezed all the right elevator trailing edge rivets. These were partially set previously, and I was really happy with the way the edge came out. It looks perfectly straight, and there is less surface scratching than I was getting with back riveting. I should have bought these earlier, and would recommend them. It’s a shame this is the only place I can use them on the aircraft.

Then I set the aft 3 rivets along each edge of the elevator, too and bottom. The last two on each side are pop riveted because of the lack of clearance.

Then I rolled and riveted the leading edge. Having done the rudder and left elevator, this seemed to be much easier. I used my highly specialized tools from earlier (popsicle stick on a piece of tube) and was able to get good rivets into each hole.

I did make a mistake unfortunately, and placed the bottom skin over the top skin on the very outboard section. This is a bummer, because fixing it will be very hard without making a real mess. I guess this will be a distinguishing feature on my plane. It won’t be very visible to the casual observer.

Last night I rolled and clecoed the left leading edge, and tonight I riveted it together. I also drilled a 1/16 inch hole for safety wiring.

Rolling the skins was generally easier than it was for the rudder. The experience from the rudder helped, and the process went faster. I used a 3/4 inch pipe and duct tape to get a good grip and a nice even bend. Using a couple of pipe wrenches helped, and I was pleased with how it turned out. It’s definitely a non-precision exercise though, and it seems like there should be an easier way.

I made up a couple of tools to assist with the riveting, by attaching some popsicle sticks to lengths of tube and aluminum channel. These were helpful is holding the bottom skin (the inside skin) against the top skin, which forms the outside of the join. Without any pressure from inside, it’s hard to keep the two skins close together when setting the rivets.

I’ll be interested to see how much adjustment will be needed once the elevators attach to the horizontal stab.

Just a few minutes in the garage tonight, so I riveted the close out tab on the left elevator. These pop rivets were easy, but the last squeeze didn’t remove the rivet stem, so I carefully cut it off using some cutters.

Today I riveted the left elevator trailing edge. I followed the vans recommendations and did this in two steps; slightly setting the rivets, then coming back and fully setting them. I used a squeezer to apply just enough pressure to get the rivet to grip the skins, then alternated sides and holes, distributing the rivet squeezing across the holes. This helps keep the trailing edge straight. Once done, I checked it for straightness, then set up my back-riveting plate. I used a long 8 foot length of steel, and set it up on several blocks of wood. I taped the trailing edge to the back riveting plate, and clamped the plate to my workbench. It’s not great since it’s not an angle, and so it sags and bends if not supported. Since the left edge is short, I wasn’t too worried. I also tried to prevent scratching by putting a thin piece of masking tape along the very edge of the back riveting plate. Setting the rivets was easy, and it worked out, but I did some some abrasions on the trailing edge top skin, which is annoying. I also realized that my trailing edge breaks are excessive, and I shouldn’t have used as much pressure as I did.

Here’s a picture right before back riveting. At this stage all the trailing edge rivets have been partially squeezed.

Tonight I riveted together the servo and the cover plate. The cover plate screws into the bottom of the left elevator, attaching to the plate nuts on the reinforcement plate. The servo is attached to the cover by two C channels, which sit on either side of the servo and orient it correctly. This was a quick and easy step, except for the countersinking of the plate. I spent some time enduring I had my countersink set correctly, because the plate is right at the minimum thickness for countersinking. I’m fairly happy with the way it came out, although one of the rivets is sitting very slightly proud of the plate. I’m not sure why that happened, but it’s not an issue.

With that done, I went ahead and removed the backing on the elevator trailing edges, and set weighted boards on each. Letting this bind overnight will help ensure the edge stays straight. I’m using a shelving support C channel from Home Depot to keep the edges straight. This channel has holes that are perfect for clecoing, and allow you to keep a very straight edge, while the tape’s glue sets overnight. I also added a weighted board to hold it down flat.

While the tank sealant cures, I worked on the next few steps. I shaped the hinge pin by bending according to the specs. It took a few bends before I had a shape that works satisfactory. I definitely need some more practice bending these things.

Then I counter sink and dimpled the trim tab servo attach plate. This plate is attached by screws to the left elevator. On the top of the plate sits the trim tab servo, which is riveted to the plate. I should be able to finish up this piece over the weekend. It’s interesting to finally get into some wiring and electronics for a change.

Tonight I glued in the foam ribs on both elevators. I mixed up a batch of tank sealant, then applied with a gun and a popsicle stick, getting a smooth even coating. I started with the left elevator, then the right, and then weighed down the top skins to ensure the skin stays in contact with the ribs while the sealant cures. I’ll let these sit until the weekend, then can start riveting the trailing edges.

I realized the plans don’t have a step for riveting the final outboard holes in the rear spar, so I went ahead and riveted them.

Then I set the trailing edge up for riveting by cleaning the wedges, applying double sided tape, and locating them on the bottom skin. I used a couple of channels to keep the trailing edge straight while the tape cures overnight.