Making a heater valve bracket

Hours: 1.5

Time to turn my cardboard prototype into a permanent bracket for the heater valve.

Since this bracket will sit freely, I decided to use 0.05in thick aluminum to give it some strength.

Just like the standard bracket that would usually hold the bowden cable, I designed the bracket to mount into the heater valve unit. So I added the size of the screw mount portion of the original bracket to my cardboard bracket part.

rough outline of the bracket and adding some indicators for the 90 degree bend

With the outline made, I got out the aviation snips and started cutting out the bracket.

Bracket cut and 90 degree bend location marked

Next step, releasing some tension. To make the bend, I mounted the bracket along the bend line in my bench vise. And then gave it some gentle (read strong) taps with the rubber mallet to form the bend.

Bracket mounted in my bench vise with some wood to bend it along

Whacking the bracket to form the 90 degree bend (very satisfying)

And here it is, a nicely formed 90 degree bend.

New bracket along with the original bracket to check the bend is aligned

Next I deburred all the edges and rounded out the corners.

And then I match-drilled the holes to mount the bracket to the heater valve using the original bracket.

Match-drilling the bracket holes using the original bracket as a template

Finally, time to mount the servo to the new bracket. Quick test fitting with a clamp to get the travel distance right.

And then I drilled and mounted it to the bracket.

And here it is in action:

More Cabin air servo work

Hours: 2.5

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With my cabin air servo mount worked out for the right side, time to translate it to the left.

I started with my cardboard pattern to match everything up for the left side. Everything looked good, so I started cutting out the bracket out of 0.032in aluminum stock.

I recently ran across this very helpful video on how to properly use aviation snips. This made it a lot easier to cut things like the bracket.

Cutting the bracket using some of the tips from the video to cut a sacrificial strip of metal to keep everything straight.

Cutting the bracket out of 0.032in aluminum

Cutting a sacrificial strip to keep the rest straight

Once I completed cutting it, I removed the protective plastic and rounded the corner and edges.

Then time for the final test fit in the airplane before match drilling the holes.

match drilling the holes that attach the bracket and vent to the side skins

All worked well, here’s the completed test fit in action:

Cabin Heater fluid valve

The third and final modification I’m making in the cabin air department is the valve that controls the heater fluid that runs through the heater.

The standard installation controls this valve using a Bowden cable connected to a plastic switch to be mounted in the cabin.

So on to some prototyping to figure out a bracket to operate the valve using the servo instead.

Figuring out the travel distance of the valve

With the travel distance figured out, time to mock up a bracket

Mock bracket mounted and servo "installed" to test it working all together

Looks viable, here’s the cardboard prototype in action:

Fabricating the air vent servo mount

Hours: 1

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As I mentioned a while back, I am going to use a servo to control the butterfly valve that controls the flow of outside air for the cabin instead of the manual “school bus handlebar” that the kit is designed with.

With the assembly of the Rudder pedals that sit right below it done, I now moved on to actually putting this together.

I temporarily placed the dash in place to make sure there won’t be any interference with the bracket I designed for the servo mount.

Temporarily mounting the dash to check placement

All looked good, so I moved on to fabricating the bracket I designed earlier out of cardboard.

I decided to use some 0.032in thick aluminum to give the mount some stability and rigidity.

Tracing the template onto my 0.032in aluminum sheet stock

cut out aluminum bracket, waiting to be deburred

After that I match drilled the hole for the servo mount through the template, marking the hole using a center punch.

Then I mounted the bracket in the plane using some clamping clecos in order to match drill the holes from the air vent.

clamped in place to match drill the marked holes through the cabin skin and the bracket

With both holes drilled I then clecoed the air vent in and mounted the servo for final testing.

air vent clecoed to the side wall and bracket and servo installed

I’ll shorten the screw of the servo mount as it’s a bit longer than it needs to be as can be seen above so it won’t interfere with the parachute cable.

Here’s a video of it in action:

Now I just need to replicate it for the left side and then I need to install it permanently.

Assembling the Rudder Pedals

Hours: 3

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So with me moving on working in the Fuselage I did some rearranging of my garage workshop.

I moved the wings back into the corner. I also turned the Fuselage around to have easier access to the flight deck. (The latest FAA’s handbooks says that even a small Cessna 150 is now a flight deck and not a cockpit 😀).
To get around easier, I also moved one of the work tables up and formed a T-shape.

I am going with the standard Sling configuration of T-bar rudder pedals and the central brake instead of differential braking.
This makes the installation and setup simpler without the hydraulics in the pedals. When I did my test flight of the TSi it was easy to steer it without differential braking.

I inventoried all the parts for the rudder pedals the other day. It took a bit to find the pedal hardware bag. But luckily Juliana found it buried in my mountain of hardware bags on the table in the background.

I noticed that the right side pedal bar had cleaned up attach points, but the left side was missing it. So I had a bit of shaving it off to do. It was pretty easy using a utility knive and then a bit of sand paper to finish it off.

Before removing the paint for the control points

After removing the paint for the control points

With that bit cleared up, all I had to do was slowly build it all up. I had to do a lot of moving left and right of the Fuselage to be able to reach down to put everything in.

The empty bracket for the rudder pedals to install into

clecoing the brackets that hold the pedals in place

With the bottom brackets installed I started putting it all together.

Pedal bars in place and moving freely with the removed paint on both sides.

Top of the brackets clecoed in place that lock the pedal bars in place and final testing for easy free moving of both bars.

With the brackets in place, I then temporarily put together the stops with the AN bolts. That way I don’t have to go looking for the hardware later when I attach the rudder cables to the pedals.

Temporary installation of the stops with the AN bolts (but not tightened, since the rudder cables will connect to them).

The next step was to rivet the brackets in place. This was trickier than I thought due to the tight space. In retrospect I should have temporarily put the brackets together before putting them in, which would have made reaming the holes a lot easier since I couldn’t fit my drill in properly, so I had to turn the reamer bit with my hand for a bit.

And finally, attaching the pedals to the bars. There are 3 possible depths and I’m not sure yet which will be the best fit. For now I put them on loosely until I have fit the seats and can do a test sit.

Completing the rear seat

Hours: 4

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After a bit of a hiatus, back to building.

With the help of my other half, we completed the bottom part of the rear seats and put it all together to finish it. This was truly one of those tasks where 4 hands can finish it all in half the time.

With everything clecoed together and fitted, time for some rivets.

Once that was all riveted together, we combined the bottom and top bench with the hinge.

Clecoing the bottom and top halves together

Riveting the top seat back to the bench from the back.

One piece of note here as the instructions don’t quite call out what orientation the hinge should be put in place. I did a lot of test fitting to get the ideal hinge-fit for this.

Based on my testing, here’s what I did:
I riveted the top bench from the back as seen in the above picture. And the bottom bench from the front to back, in order for the bench to be able to fold forward completely without interference like this:

Riveted the bottom of the bench from front to back in order for the seat back to be able to fold down without interfering with rivets.

And here’s the happy completed picture:

Assembling the rear seat

Hours: 2

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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.

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

Lining up the rib structure of the seats

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.

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.

Next step will be to rivet it all together.

Figuring out cabin air assembly

Hours: 2

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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.

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

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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.

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

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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.

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

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

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

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.

Almost looks like a seat:

Assembling the bolt mechanism

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

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.

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

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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.

And from there it was just riveting everything together.

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

Sarah's Sling TSi Build Log

Documenting the journey of building a Sling TSi aircraft in my garage.

Making a heater valve bracket

More Cabin air servo work

Cabin Heater fluid valve

Fabricating the air vent servo mount

Assembling the Rudder Pedals

Completing the rear seat

Assembling the rear seat

Figuring out cabin air assembly

Butterfly valve servo

More front seat construction

Building a Front Seat

Assembling the bolt mechanism

Building the Left Aileron

Timelapse of building the Ailerons