Assembling the rear seat

Hours: 2

With the front seats almost complete apart from the lock pin mechanism, time to assemble the rear seat.

First order of business was to remove the protective plastic and do some inspecting and deburring of the edges and holes.

Laying out the ribs
Ribs deburred

With that out of the way, time to assemble the main rib structure.

Lining up the rib structure of the seats
Backside of the seats with ribs clecoed

On the bottom rib there was a minor misalignment of the rib. The rib extended a little bit beyond the skin, but the holes were all drilled fine.

bottom rib extended a bit too far

So I trimmed off the small part that extended too far.

Sanded it down to finish up with the skin

And on to more ribs to make it a really solid seat.

Complete rib structure clecoed to the back

The last part was to put on the front skin and make sure everything lines up. When I first clecoed it on some of the ribs didn’t align, so I unclecoed the skin again, then centered it and clecoed it again and everything fit well.

Both sides of the skin clecoed in place

Next step will be to rivet it all together.

Figuring out cabin air assembly

Hours: 2

Last week I finally received the cabin air parts after the lockdown in the past few months that put a hold at the factory for sending out new parts, but they are back up and running.

The cabin heat assembly for the TSi has a mixture of forced air from a NACA duct getting air from the outside when the plane is moving, together with an actual radiator heater, for those times where you don’t want cold outside air and instead heat it. To shut out the outside air, the TSi has a butterfly valve that’s operated by a handle from the panel.

I am planning to replace the manual handle with a servo instead and also replace the front standard plastic vents that come with the kit, with some ball vents typical in airplanes.

I got the Aveo Air Maxi Vents in black since the front is black leather, so it blends in nicely.

Aveo Air Maxi Vents

Butterfly valve servo

The servo I’m going to use is from TCW that comes with a linear servo from Actuonix, together with TCW’s control board with the control knob to operate the servo.

The first thing I had to figure out is the travel of the butterfly valve, it is around 40mm long. I made a small cardboard panel, clamped it to the bracket of the box that houses the butterfly valve. Based on the maximum extension I then mounted the back of the servo onto my cardboard panel. Then I tested that retracting and extending works correctly from that position and made small adjustments to the travel distance.

Here’s a small video of testing the operation:

With the operation figured out, then I went to check for alignments in the cabin.

First I had to figure out where exactly the vent box sits inside the cabin. Some quick measuring for the distance based on the construction manual.

Marked where the valve box attaches to the skin

Then I put in the channel that moves air to the rear passenger seats to make sure there is no interference wit the operation.

cabin box held in place, along with the channel that pulls air to the rear passengers

Looks all good. Next step will be to fabricate the bracket out of aluminum.

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

Installing the Pitot Tube

Hours: 8

After a couple of weeks of taking some time off active building while life happens and figuring out and planning out some things, I’m back to actively riveting on the airplane.

Time to finish the Pitot Tube after having cut the inspection panel hole and running the wiring a few months ago and lots of learnings about new tools, from the wiring, to flaring the tubes and connecting AN fittings.

I’m using the Garmin GAP 26 heated & regulated Pitot Tube (GAP 26-20). This version automatically controls whether the Pitot Tube needs to be heated using a regulator controller that is mounted next to the Pitot Tube and will only apply heat if needed based on outside temperatures.
This basically will allow me to always turn on the Pitot Tube in my panel as part of my standard operating procedures and the regulator will control whether it actually needs to be heated to prevent icing.

The installation instructions for this can be found in the Garmin G3X installation Manual.

After studying the installation manual to make sure I install it correctly, I measured the tube and had to figure out how far I have to cut it in order to fit.

Fitting the Pitot Tube

The Pitot and Angle of Attack (AOA) mast are over 12 inches out of the box, and that won’t fit. I made an initial guess and cut a bit shorter, but I was still too long so I made a series of shortenings and test attaching the fittings until I had it dialed in.

First test fit shows that the masts are too long and need to be cut further.

In the end, I had the masts cut down to right around 8 1/2 inches. The Garmin manual says to keep a minimum of 8 inches between the probe and transition to non-metalic tubing, so I had a little bit of margin.

Time for flaring the tubes. The AN fittings use a 37 degree flare, so I got a Rigid 377 flaring tool and a metal tubing cutter to cut the tube. Before doing this on the real Pitot Tube, I made some test flares on a spare tube I bought from Aircraft Spruce.

Make sure you put the AN fittings onto the tube before you do the flaring (I may or may not have forgotten it the first time and cut and redo the flare once).
Make sure you put the AN fittings onto the tube before you do the flaring (I may or may not have forgotten it the first time and cut and redo the flare once).

After I had that dialed in, I did another test fit to get the length correct, accounting for the bend towards the tube and then mounted the fittings.

Mounting the fittings to the tube.

Final fit and connecting to the nylon tubes inside the wing after having cut the nylon tubes.

Final fit and connecting to the nylon tubes inside the wing.

Installing the regulator and wiring

With the Pitot Tube itself installed, time to finish the regulator and wiring that controls the heating of the Pitot Tube.

As I explained previously, I plan to mount the regulator unit onto the inspection panel plate, so I did some measuring and orienting to make sure the twist action of the round plate wouldn’t interfere with the wires coming out of the regulator.

Here is the final orientation that I figured out would work best (the screw will mount to the bottom, so the wires will come out the top):

Here is the final orientation that I figured out would work best (the screw will mount to the bottom, so the wires will come out the top).

I contemplated between screwing or riveting it on, but I figured that it’s unlikely that it will need to be changed out frequently, so I riveted it onto the plate.

Completed inspection panel plate with the Garmin Regulator mounted.

The last part was to create a connection from the regulator to wires I ran through the wings. I used some weatherpack connectors for this, which create a waterproof connection and a solid crimp, similar to the Delphi GT 150 that Midwest Panel uses to connect the wiring harness.

Crimped wires to connect to the regulator (blue connects to the panel to communicate with the G3X to see whether Pitot heat is active)

Final completed connection between the regular, the Pitot Tube and the wires running to the center.

Final completed connection between the regular, the Pitot Tube and the wires running to the center.

Installing the plate to the wing

The last and final part of the installation was to mount the inspection panel plate onto the wing. I did this last to prevent scraping up my arm while I had to do all the mounting inside the wing, since the backing plate that holds the plate in place has a series of pokey corners that love to eat airplane builder blood.

First I lined up the plate with the wing and then did the match drilling of the holes:

First I lined up the plate with the wing and then did the match drilling of the holes.

The I dimpled the plate and the matching holes on the wing and riveted it in place.

The I dimpled the plate and the matching holes on the wing and riveted it in place.

And here is the completed and closed up Pitot Tube and Inspection Plate that holds the regulator:

And here is the completed and closed up Pitot Tube and Inspection Plate that holds the regulator.

Timelapse of the entire installation

How to get started

I had an email conversation with a new future Sling TSi builder over the past two days. While he is waiting for the kit to arrive, there is the hard question of “how to get started”. This question comes up for every new builder, and those that haven’t made up their mind yet, but need some guidance on what it would take to actually get started.

Getting Started

I remember from my own journey of when I got started, that the sheer amount of information out there can be overwhelming and finding some kind of guide-posts can be helpful to make a start.

So I’ve written up a page on my blog on how to get started, from considerations about the workshop, to a few books I found helpful and the large list of tools you’ll need.

I hope this will be helpful to future builders and those evaluating their options.

Walkthrough of my workshop

It’s been a while in the making after a few requests over the past several months, so I finally took the time and do a walkthrough of my Workshop where I’m building my Sling TSi.

Apart from walking through my garage workshop setup and a bunch of the tools I’m using throughout the build, I’ve also given a small update on my current tasks. I’m waiting for the balance tube to finish off the ailerons and I’m currently finishing up the installation of the pitot tube, after running the electrical wiring the other day.

I’ll make a separate post on the installation of the pitot tube when I’m done, but here’s a preview picture of the first fitting to figure out the length of the tubing:
Fitting the pitot tube to figure out the correct length of the tubing