First order of business for the Elevator skin was inspecting all edges and holes and there were a few edges that needed some deburring action.
After deburring everything that needed attention, we wrapped the skins around the rib structure. Since the Elevator is a pretty big part, it was very helpful to have a second pair of hands for this.
The last thing I had to do before I can start on closing up the skin is to install the backing plate for the Trim motor inspection plate. The plans call for 1/8 rivets, but the holes were actually 3/32, so I had to first up-drill them. There’s also another small error in the plan, in that it says to rivet all 8 holes, but actually only 7 should be riveted, since the top hole is for the screw that holds the inspection plate in place.
Time to finish off the Empennage and get the Elevator structure going. I received the replacement ribs that are bent just that little bit more in order to properly align with the reinforcement plates and skins and went to work to drill out the bad ribs and put in the replacements.
After that, I went to work and torqued the bolts that connect the control rod and counterweight to the Elevator. There’s also a small support bracket that reinforces the center rib to spar attachment, which is a pretty tight fit, so I had to get out the manual hand riveter.
My brother is currently visiting and is enjoying the riveting experience.
Once the center ribs were finished, we moved on to put the rest of the rib structure in place.
After that I realized there’s a mistake in the plans as they instruct to rivet the edges that hold some of the side counterweights on, but there’s another small end rib that actually has to go on there as I found out after I checked the overall plan for the Elevator. Quickly drilled out the rivets and riveted on the part. A nice trick I learned from another builder for drilling out the rivets without damaging the holes they go through, is to only drill out the top of the rivet (the donut ring) and then use the center punch to push out the back of the rivet. This way you have less chance of enlarging the hole.
With the rib structure in place, time to work on fitting the skin.
With the ribs for the Flaps out of the way, I am ready to finish the flaps. First order of business is to ensure that I have the ribs all in the right order.
Once that was figured out, I first clecoed the ribs in place to the bottom of the skins and then closed up the skins and clecoed the top as well.
After checking that everything is aligning properly with the skins, I started riveting the skin. The top side is pretty straightforward. For the bottom side, there are a couple of tight spots next to the hinges, so the close quarter rivet wedge came in handy for a couple of the rivets.
With the right side Flap finished and closed up, I then repeated it all for the left side Flap. There was also a couple of the edges where the hinges sit that needed a bit of deburring attention.
After I finished the top skins, I did one quick alignment test fit on the wings and everything looked good, so then I finished up both sides by riveting the front rivet lane that closes the skin against the other side.
Final alignment check
Once I finished all the riveting, I did one final test fit onto the wings. I used a bit of mason string and my laser level and everything is looking good. Now onto finishing the Elevator.
With the priming of the Flaps ribs out of the way, I got started riveting the Flaps. First order of business was laying out all the ribs in the correct order.
After laying out the ribs in the correct order, I started laying out the right hinges to go with each rib. There is one interesting rib that needs to be riveted in two steps as one part goes on top of the other:
Once I figured all of that out of the right side Flaps, I repeated the steps for the left side Flaps:
I received the missing rivets for the assembly the other day, so now I was able to finish the riveting all of the hinges to the ribs to actually complete the flaps.
With the wiring finished and the Antenna fitting done, I am now finally able to close up the Vertical Stabilizer and rivet the skin.
To begin, I closed up the left side of the skin and held it in place with clecos, since this is the side where the Antenna slides through the enlarged rivet hole, while on the right side I had to create the custom notch so that I can pull the skin around the Antenna.
Once that was done, I riveted on the support plate for the Antenna onto the top rib of the Vertical Stabilizer.
Now that the structure is complete, time to mount the Antenna permanently in place. Using two 20mm long M4 screws, washers and Nyloc nuts and some medium strength threadlocker I mounted the Antenna in place. Here’s the Antenna mounted in place and the wire connected to the Antenna using the BNC connector I crimped onto the wire.
Riveting the skin
With all the prep work finished, I closed up the right side of the skin, made sure everything fits correctly and clecoed it in place. There are two holes on the bottom on each side that are not riveted, but instead I have to install Rivnuts in them, so I marked out those holes, so I don’t accidentally rivet them.
There were two rivets that I had to shorten in order for them to fit flush near the Antenna. So I made a small template for the dept through a piece of wood and then shortened them accordingly.
After that, it was just a matter of pulling the many rivets on both sides of the skin to close the Vertical Stabilizer up for good.
The last part was to install the two rivnuts on the bottom on each side, so after enlarging the holes using my step drill and reaming them out using my hand reamer, I got out my rivnut puller and high strength loctite and put those in place.
With the Vertical Stabilizer completed, I then did a quick test fit and mounted it on top of the Fuselage and also attached the Rudder for a moment – almost looks like an airplane.
After finishing attaching the rivnuts to the rear spar parts the other day, I put everything together and did a brief test fit with the Fuselage where it attaches into.
After putting together the rear spar, I also enlarged the holes in the spar so that the M4 screws can actually be screwed in and enlarged the bottom two holes so that the bottom rivnuts sit flush with the spar. ,
Looked all good, so onto riveting together the inner structure of the Vertical Stabilizer.
I also enlarged the holes for the wiring and added snap bushings since the inside won’t be accessible once it’s closed up and the snap bushings have a better durability than rubber grommets.
There was one spot on the rear spar where one rivet was very close to one of the rivnuts and I had to use my manual hand rivet gun to pull the rivet as the head of the Milwaukee was too large to get in there.
Completed inner structure of the Vertical Stabilizer:
After putting the Elevator construction on pause due to the alignment issue of the center rib. I decided to get started on putting together the Vertical Stabilizer. I’ve heard back from the Factory and it turns out that they’ve changed the Rib and will be sending me the correct new versions of the ribs (EL-RIB-001-C-E-1 & EL-RIB-101-C-E-1), so I’ll have to wait until I get those.
So onto the Vertical Stabilizer – the bottom of the rear spar holds a lot of M4 Rivnuts, so it was time to updrill the holes to the correct size in order to fit the rivnuts.
Using the step-drill bit I enlarged the holes just a bit smaller than the Rivnuts and then finalized it to the exact size using a hand reamer since you don’t want the hole to be any larger than the not so it gets a tight fit.
After all that was done, I put together the spar with the brackets for a quick test fit. While doing so I also found an error in the instructions, which say to rivet the hinges on the bottom with 8 (4 a side) 4mm rivets, but actually, only the center one (where I have black clecos) should be riveted, the outer ones will be bolted to the Fuselage (which is why they have larger holes already and I temporarily used the larger golden clecos to hold it in place), so I sent the Factory a note to correct the instructions.
With the weather warming up, I got to spend some time sitting in a bit of sun with the garage door open and preparing, deburring, cleaning and then priming more parts of the Elevator.
Assembling Elevator center spar
The first thing I put together was the Center Spar itself, which I had primed already together with the counterweight the other day. Setting everything up was pretty straight forward as usual and while I was working on it I had a visit from another builder of the EAA chapter I’m part of who actually happens to live very close by and is building an RV. And then another friend was visiting and I happened to have some rivets ready to be riveted, so I continue my new tradition to have guests pull a rivet on the plane and sign it.
Assembling the center structure to the spar
After the priming from yesterday had some time to dry and set, I went to work to put together the center rib assembly with the center spar. There are a lot of pieces that slot together in there, so it took some time to figure out what slots into which piece. for the center channel to go on:
Unfortunately I encountered a problem with the alignment of the holes on the center Rib, both left and right, with the plate as seen below:
In trying to figure out which piece is wrong, I started putting together more of the structure temporarily with clecos and the strange thing is that the other holes on the ribs are aligned fine (the black clecos below), so then I thought that it must be the top center plate.
But then I took off the center plate to check its alignment with the outer skin and there the holes of the top center plate align correctly with the holes on the skin. So this in turn then lead me back to determining that the top (and bottom) holes on the Rib 1 must be the culprit.
It is very strange since the misalignment is pretty severe. It definitely doesn’t look like this could just be resolved by up-drilling the holes, so I sent a note to the factory to ask how to proceed. My guess is going to be that I need new center ribs.
While I was waiting for some parts to complete the ribs for the Vertical Stabilizer, I got started working on the Elevator. Since there are a lot of parts to the Elevator I broke it down into smaller tasks, first preparing the parts of the center counterweight and then I’ll continue next with the other parts of the structures.
So onto another session of preparing the parts, deburring holes and edges and cleaning with Simple Green & degrease with MEK. After that was all done it was back into my small paint booth to prime everything.
Riveting the Elevator Counterweight
After all that had time to cure for a day I went to work to put together the center counter balance weight support (that’s a mouthful).
I found a small error in the instructions that say that there are 14 rivets in the center, but it’s actually 16 rivets. Sometimes with these small errors I wonder if they are intentional to keep us builders on our feet to make sure we “measure twice and drill once” – I sent the Factory a note to correct the error in the instructions for the next iteration.
So after I laid out all the parts I put everything together using clecos and the two AN3 bolts and then went to work riveting it together. A friend was visiting from Ireland as well, so after a tour of the garage and everything he also pulled his first rivet and I had him sign his name under it.
Rudder Timelapse video
I also recently finished editing together the work on the Rudder, so here’s the completed Timelapse video:
After having primed the inner surface of the Rudder skin the other day, I had all the pieces together to start working on finishing the rudder.
I attached the skin onto the structure and clecoed it into place.
Fitting the fiberglass tip
Once that was done, I went to work to fit the fiberglass tip onto the skin. I had to trim a little bit away from the bottom of the fiberglass. I made a first rough measurement, trimmed it away using my Dremel and then tried to fit it in.
After aligning it all, I did a second small pass to trim a tiny bit more, placed it into the skin again and then it looked all good.
Since the instructions are very explicit to make sure that the alignment of the rudder is perfect, I checked the alignment from all sides and it all looked good.
After all that looked good and triple and quadrupple checking that the fiberglass tip sat flush in the skin I made marks for match drilling the holes and then went to work and carefully drilled the holes into the fiberglass.
Countersinking the front of the fiberglass tip
Once that was done, it was time to countersink the holes in the front. The instructions contradict themselves – only the first 7 holes get countersunk rivets, which mathematically adds up properly to the 32 rivets (2 x 7 on the top and 2 x 9 on the bottom = 32). So after counting all the holes and re-checking the instructions and doing basic math, I decided to only countersink the first 7 holes. I sent an email to the factory yesterday and they confirmed that I was right and they’ll fix the instructions in the next iteration.