Tag Archives: riveting

More front seat construction

Hours: 4

With one front seat assembled, time to complete the other one.

I got an AN3-6A bolt from a friend while waiting to get a replacement from TAF, so I was able to put together the seat locking mechanism for the seat.

Completely assembled seat locking mechanism, ready to rivet

EDIT: after reading the Sling 4 instruction manual, I now believe the cable goes on the other side, so I’ll move it down before I close it up and rivet it in.

Now having figured out the complete assembly, I also assembled the mechanism for the second seat, but unfortunately, the steel cable assembly for the second seat is too long, so I put in an order for a replacement.

Second seat locking mechanism put together, but unfortunately the cable on this one is much too long.

So one mechanism assembly completed, the other on hold.

Then I completed assembling the second seat itself. When I built the other seat I noticed that I was missing some screws for the hinges and put in an order to get the missing screws, but I also remembered that I got some various metric screws from boltdepot a while back and luckily I had some countersunk M4x12 screws . Ialso found that there’s a typo in the instruction manual, which says they are M4x10, but the part number is HW-CAS-412-X-X-0 and they are actually M4x12. So I was able to put together the side hinges with those.

Riveting the headrest
Riveting the seat hinge

Now I just need some upholstery to make them a bit more comfortable to sit on. I ordered the upholstery a few weeks ago, so they should arrive in a few weeks hopefully.

Building a Front Seat

Hours: 3

It’s time to replace the now empty box of parts in the Garage with another full one. I moved on to the Fuselage box to get started with the interior of the Fuselage assembly. First order of business was finding all the parts for the seats.

After a bit of digging I found all the parts for the seats based on the inventory checklist in the box.

Laying out parts for the seat assembly

Once I had all parts in order, I started laying out the headrest based on the manual.

Ribs for the headrest
Ribs for the headrest clecoed

Then I clecoed it all onto the seat back and started riveting from the seatback.

Riveting the front of the headrest

Following the backside, riveting the front side of the headrest.

Headrest riveted

With the headrest completed, time to make it look like a seat. I checked out the detail diagrams for the hinges and put everything together. The holes of the hinges needed a tiny bit of enlarging which I did using a simple hand deburring tool.

Seat hinges needed minimal enlarging to fit the linkage

Once I had the side hinges completed, I cleoed and riveted the bottom hinge of the seat in place.

Riveting the bottom seat hinge
Riveted the bottom seat hinge

Almost looks like a seat:

Seat almost completed

Assembling the bolt mechanism

The only thing left is the bolt mechanism that allows the seat to lock in place inside the Fuselage.

Laying out the bolting mechanism

Unfortunately, this is where I found out I was missing something. The bolt that allows the pulley to pull the cable wasn’t quite long enough. It should be a AN3-6A bolt, but as it turns out, it’s a 5A bolt, so it’s missing the mark by just a hair.

That bolt is unfortunately only -5 long

Also I only got one bolt, set of washers and screws for the hinges, which (if it was the right length) is only enough to complete one seat, so I put in an order for the few parts and will give them a call in Torrance to see if they can send they few screws so I can complete the seats.

Here’s a picture of test fitting the mechanism with the slightly too short bolt:

Half assembled mechanism to see how it functions.

Building the Left Aileron

Hours: 1.75

With the right Aileron completed, time to build the left Aileron.

Since I figured out the order of assembly last time with the right Aileron, the completion of the left one was very straightforward.

I set in the ribs, then added the balance tube and then went to work clecoing everything together.

Ribs clecoed to the bottom and balance tube inserted in the front.
Top side clecoed and ready to rivet.

And from there it was just riveting everything together.

Bottom done, top ready to rivet

Another quick alignment check before riveting the front line and then I riveted the front line and completed the left Aileron.

Both Ailerons completed

Timelapse of building the Ailerons

Finishing the Right Aileron

Hours: 2.5

With the ribs for the ailerons prepared, time for me to complete and rivet the ribs and the skins to make a complete Aileron.

The instruction manual on the Aileron is still a bit light, so I first had to figure out the order of things. After first doing it wrong and placing the balance tube in first, I realized that this doesn’t allow to place the ribs. So back out with tube, and in with the ribs first.

Lining up the ribs inside the aileron

After I aligned all the ribs I inserted the balance tube and lined it up with the rivet holes. Then I clecoed both sides to start riveting the top and bottom of the skins.

Clecoing the right Aileron
Starting to rivet the top

After I was done with riveting the top and bottom of the skins, I took off the clecos from the front and did a test fit on the wings to check the alignment.

Checking alignment using a mason line
Checking alignment using a mason line

Everything looks good, so I clecoed the front line again and started riveting to finish the Aileron.

Riveting the balance tube
Clecoed the front line after checking the alignment

And here’s the completed right Aileron:

Completed right Aileron

Aileron Ribs

Hours: 1.5

Time to finish off the external control surfaces with the Aileron. I already primed them a while back, so time to assemble the ribs.

First order of business was sorting the ribs between left and right aileron. Then I checked off all the hardware needed. I already knew from my earlier investigating that the AN bolts for this is in the finishing kit, and the eyebolts are attached to the control rods.

Right Aileron ribs laid out in order

After laying them out, I started riveting the control brackets using the 4.8 mm rivets.

Riveting the hinge bracket 1 to rib 2

Then for rib 7 I laid out both brackets. The instructions are missing details about this rib, but it was easy to figure out that it uses the remaining 4.8 mm rivets (24 total per the part list, 9 are used for bracket 1, and counting out the holes of bracket 2 and 3, it comes to 24). I also noticed that one bracket slightly overlaps the other, which means that first I had to fully rivet the bracket 3:

First riveting the bracket 3

With this completed, I then riveted the hinge bracket 2.

Riveting bracket 2 which floats over bracket 3

The final rib that needs preparation is the assembly of the Eyebolt attachment that controls the movement of the aileron. I put it all together and then torqued it and placed some torque marker on it.

Completed assembly of the control rod attachment.
Complete assembly of the control rod attachment rib and torque marker on the torqued bolt.

Then I repeated everything for the left Aileron ribs. Next step will be to lay all the ribs into the skins and rivet it closed.

Completed left Aileron ribs
Completed right Aileron ribs

Finishing the Elevator

Hours: 2.5

With most of the preparations out of the way and half of the skins riveted, I took one more session to finishing the Elevator.

There was only one extra part I had to do for 3 of the rivets that were on the bottom edge. In order for them to fit correctly, I had to shorten the rivets so they wouldn’t protrude out.
Rivet too long to fit Fitting rivet after I shortened it I mounted the rivet in my bench vise and filed it down to size Shortened Rivets on the right and one with normal length on the left

Aside from that, I just went to town and pulled the rest of the few hundred rivets.
Time to pull some rivets Halfway done riveting the skins Final set of rivets ready to be riveted Riveting the Trim Tab

The last part on the riveting side was the front lip.
Clecoing the front lip Riveting the front lip

One of the holes on the lip has to be enlarged to fit a grommet for the wiring for the Elevator Trim Tab. I enlarged the hole using my step drill bit and then installed a snap bushing.
Marked out the hole that needs to be enlarged for the wiring Marked out the size on the step drill bit Hole enlarged and Snap Bushing installed

The last part was to install the center balance counterweight. I did some test fitting with this, but the AN3-13A bolts that one of the versions of the manual that I have mentioned are too short, so I’ll check with the factory on the proper length.
Test fitting the Balance Counterweight - the bolts are too short

With that being said, the general assembly of the Elevator is completed:

Timelapse of the complete construction of the Elevator

With the Elevator construction completed, I’ve also finished my video timelapse of the process:

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

Elevator skin fitting

Hours: 3

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.
Elevator skin edges needed some filing to remove the burrs

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.
Backing plate goes under the skin Holes are 3/32, so I needed to up-drill them to fit the 1/8 rivets Holes up-drilled and backing plate clecoed in place Quick test fit of the inspection plate

Elevator structure

Hours: 5.25

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.

New ribs in place and a final picture of a few rivets that people that visited helped pull

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.
Torquing the AN bolts Bolts torqued and support plate riveted

My brother is currently visiting and is enjoying the riveting experience.
My brother enjoying the riveting experience

Once the center ribs were finished, we moved on to put the rest of the rib structure in place.Elevator rib structure finished Clecoing the ribs 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.
Error in the plan says to just rivet the endcap, but actually this part needs to be riveted onto the side End rib where it should go Holes drilled out and end rib ready to rivet

With the rib structure in place, time to work on fitting the skin.

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