Tag Archives: alignment

Riveting the Elevator skins

Hours: 3.5

With the final preparations and alignments of the Elevator done, the last task is to rivet up the Elevator skins.

Horizontal Stabilizer and Elevator temporary joined for alignment and looking good

The process is pretty straightforward, but there are a lot of rivets to be pulled, so it’s a lot of repetition, so I spread the work out over a few sessions.
Setting up rivets Almost done with the left underside Finished left underside

I first did the half of the bottom, both left and right side, and then finished up the left side completely, followed by the right side.
Setting up the final few rivets for the right underside Bottom of the entire Elevator completed

For the Trim Tab control tabs I had to get out the close quarter wedge.
Using the close quarter wedge to be able to attach the rivets for the Trim tab Control

After I finished the entire bottom half of the Elevator I flipped it around and put a small padding onto the Trim Tab control so it can’t dig into the Elevator skin.
Protection for the Trim Tab control

Final Elevator fitting

Hours: 2.5

After reinforcing parts of the fiberglass tips for the Elevator for the front section that is countersunk to support the flush rivets, I finished fitting of the right side of the Elevator.

When I finished the alignment of the left side of the Elevator, I ran out of clecos, so I bought a couple more when I was at Oshkosh so I could properly put the Elevator together and get everything to align correctly.

So the first order of business was to finish clecoing everything including the (correct) control tabs for the Trim Tab.
Time to cleco the right side of the Elevator Everything clecoed together including the Trim Tab

With that out of the way, I moved on to do the fitting for the right side fiberglass piece. It took a little bit of aligning and filing away a tiny bit from the back so that the fiberglass piece can slot into the metal.

Once that looked all good, I started to do the match drilling of the holed into the fiberglass.

Time to drill some holes into the fiberglass tip First hole drilled and clecoed Continuing the match drilling All holes drilled

Now the only last part to do was to countersink the front parts of the fiberglass tips in order to allow the flush rivets to sit in there. It took a bit of back and forth to calibrate my microstop countersink attachments to ensure I had a good flush fitting.

Marked out for the holes that need to be countersunk Finished countersinking the holes Flush fit of the left side Alignment checks on the right side

Elevator Trim tab & left fiberglass tip fitting

Hours: 4

With the two main skins fitted onto the Elevator, I started looking at the trim tab and the side fiberglass tips.

First I figured out the correct orientation of the hinge that connects the Elevator and the trim tab and the right orientation of the trim tab. I temporarily clecoed them together to check that the clearances are good and it moves all fine.
Elevator trim tab temporarily mounted

Then I was searching for the brackets that go on top of the trim tab and realized that I got two different looking brackets. Since this looked off to me, I tried to squint real hard at the instruction manual to figure out which bracket is the right one. I also checked the Sling 4 instructions and asked Matthew if he had a picture of his brackets and with that figured out that I must have received one TSi and one Sling 4 bracket, so I put in a note with the factory so I can get the right bracket for my TSi.
This looked off to me - I figured out it's one TSi and one Sling 4 Trim tab bracket
Investigative work to figure out which bracket belongs

Securing the trim tab piano hinge

With that out of the way, I focused on thinking about securing the piano hinge that attaches the trim tab to the elevator. Since there is no natural stop for the pin that goes through the hinge on either side, it could happen that it becomes lose from vibration and thus could come out during flight, which would be bad. I research a bit on the topic and found this article from EAA on the use and installation of piano hinges.

One of the ways to secure the hinge is to drill a small hole through the last part of the hinge and install a safety wire. My hinge was luckily cut in a way that makes this approach very easy to achieve. I got out a small drill bit, mounted the hinge in my bench vise and drilled a hole on each side so I could run a safety wire through it.
EAA diagram to safety the hinge Hinge mounted in my bench vise to drill the hole for the safety wire Hole drilled for the safety wire Safety wire in place to test free movement while connected to the Elevator

Using the safety wire approach makes it easy to still remove it in the future, but ensures that the pin stays securely in the hinge.
Testing free movement of the trim tab with the safety wire in place

Fitting the left side fiberglass tip

For the last part of the day, I started on fitting the last part of the skin and the fiberglass tips. Since this requires moving around the tip from both sides, I moved the Elevator over onto some saw horses so I could access the bottom more easily.

First I clecoed the top skin in place and then I slowly fitted the fiberglass tip in place. In order to get the fiberglass tip to fit, I had to file a tiny bit at the back, but it was much easier than the Rudder tip fitting.

Once I had it in place, I started to hold everything tight together and started match-drilling holes into the fiberglass tip. I used liberal amounts of clecos to get a tight fit and everything looks good. Now I just need to repeat it on the other side.
Top skin clecoed in place Fiberglass tip fit in place and ready to match-drill Marking drill holes Fiberglass tip match-drilled

Finishing the Flaps

Hours: 6

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.
Completed ribs laid out along the right Flap

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.
Ribs clecoed in place to the bottom of the Flaps skin Clecos in place to close up the right Flap

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.

Rivets in place Close quarter rivet wedge to rivet the tight space next to the hinge Bottom right side Flap ready to rivet Bottom right side flap almost done riveting

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.
Some deburring was needed for the hole where the hinges go through Upside down view of the left side Flap ribs clecoed in place Almost done with the left side Flap riveting

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.
Front line ready to close up the skins of the Flaps for good Almost done riveting the Flaps Completed left Flap Both Flaps completed

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.
Final test fitting and alignment checks Final test fitting and alignment checks

Timelapse of building the Flaps

More Elevator priming & assembling center spar structure

Hours: 5

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.

Laying out and preparing Elevator parts Primed Elevator parts

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.

Elevator Center Spar Elevator Center Spar riveted

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:
Center Channel in place

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:
Rib holes misaligned with the center plate Closeup of the misalignment of the elevator rib

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.

More of the Elevator center structure in place

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.

 

Rudder Tip fitting & riveting the skin

Hours: 2.5

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.Rudder skin clecoed in 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.
First trim mark on the fiberglass tip

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.
Tip fit in place and held in place using some clamps

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.
Rudder checked for alignment using laser level Rear of the rudder checked for alignment using laser level

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.
First few holed drilled into the fiberglass tip Finished drilling all the holes in the fiberglass tip

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.
Instruction error about countersinking

Before I went to work with the countersinking, I calibrated the micro stop countersinking tool using a scap piece of Aluminum to ensure the depth was set correctly and made sure that I had the correct 120 degree pilot cutter in the tool (I made a whole post about why using the 120 degree pilot was important here).
Calibrating the Microstop Countersinking tool Making a test countersink on a scrap piece of metal

After all that was ready, I went to work, mounted the fiberglass tip gently in my bench vise and started drilling the countersink holes.
First countersunk hole drilled Checking depth using a countersunk rivetAll the countersunk holes drilled in the fiberglass tip

All the countersunk holes came out well and everything sits flush now.
Flush fit of the fiberglass tip in the Rudder

Riveting the skin

So after all that I went to work and started riveting some of the skin.Time to rivet the Rudder skin The close quarter wedge came in handy for riveting in this tight spaceRiveted part of the Rudder skin

Rudder skin fitting & Anti-Collision light mount

Hours: 3

Over the past few days I spent some time organizing the next few parts of the Empennage such as organizing the Vertical Stabilizer parts and what I needed to finish for the Rudder.

Fitting the Anti-collision light

I got the Aveo Posistrobe MiniMax anti-collision light to mount onto the rudder tip and started working on fitting it on.
Aligning the strobe light seal to find out where the holes should go Marking center linePilot holes drilled Double checking the holes aligned properly and then enlarging the hole for the wires to pass through
Light temporarily on top and shining bright like a diamond.
Quick test with light on

Mounting plate

The first iteration of the Empennage assembly instructions called out for a mounting plate to go inside the fiberglass tip to add structural reinforcement for the rivnuts, but the latest version of the instructions is missing it, so I sent a question to the factory why.

In the meantime, since I assume that it’s still a good idea since both the Sling 4 instructions as well as the first version of the instruction call for it, I decided to fabricate my own.

I started tracing out the rough dimensions of the area and then measured it down to how it would fit. Then I made a first version out of cardboard to see if the dimensions I estimated would work.
Rough outside dimensions of the strobe light traced Test fit of cardboard cutout

Looked good, so then I copied my cutout onto the sheet metal and went to work cutting it out. I used a OLFA Scoring knive to score the cut, based on a tip from HomebuiltHELP. Since my metal was pretty thick I only scored it with that and then used metal snips to cut it, but for thinner metal you can actually make the whole cut using the scoring knive to make great straight cuts.Transferred cutout onto aluminum sheet Metal piece cut and ready to drill the holes

After that, I deburred all the edges and the holes and then checked the final fit in the rudder tip.Plate fits great in the tip Clecoed in place

Fitting the skin

I also test fitted the skin onto the rudder and checked how the tip will fit in. The skin came on fairly easily, but I will have to trim a little bit of the fiberglass tip so it will fit in.
Skin fitted and fiberglass tip put in place Need to trim off a bit of the rear of the fiberglass tip

I still had to prime the inside of the skin, so now that I know it all fits together fine, I will rivet the skin on and then work on the final trimming for the rudder tip so it fits in and then I will need to match drill the holes into the fiberglass tip and countersink the front holes.

Riveting the Horizontal Stabilizer skin

Hours: 3

The journey of the Horizontal Stabilizer continues with match up-drilling all the dimpled holes to fit the countersunk rivets. So basically this, multiplied by 200:

After I was done, I took off the skin one last time to clean out all the debris from the drilling and check and fix any burrs. After that it was time to put it back together again and do one last check for alignments before riveting using my self leveling laser level.Cleaning out the debris from reaming out all the holes  Alignment checked using my laser level

And then at last, time to start the riveting. I managed to finish the bottom of the right side, so 3 more sides to go next time.

One small problem I encountered while doing the riveting was, that because I was riveting straight down, it happened twice that some of the mandrels of the 3.2 mm rivets got stuck in the rivet gun, so I had to take it apart and push/pull out the mandrels.

Mandrels stuck in the rivet gun