Ken's Sonex 1243

[Bryan Cotton]

Ken,
I found the backing plates were set up for the nosewheel Sonex. Heresy! Somewhere a witch needs to burn or something. So check that, you may need to make a set with alignment for the taildragger.

Also make sure you press in the bearing races with a hydraulic press. If you don't, your aerobrakes will slowly do it for you, meaning you will have to keep tightening the castle nut, adding washers, and generally cursing your lot in life.

I originally used 3/16" hardware but the assembly wore and the wheelpant would rotate back and forth. To make the 1/4" bolt work you will need one of those small all-metal clench nuts - NUT, STOP MS21042-4.

Looks great!

Edit: my post on the topic said this:

In the 3 point attitude the plate was 8 degrees nose down and the airplane was 9.5 degrees nose up. So, our hole pattern needed to rotate 17.5 degrees. We used this simple setup.

The pictures were lost somewhere.

Edit again: I found the picture.

We used a piece of flashing to make a template. The blue lines show the nosewheel configuration, and the red lines are our new tailwheel configuration.

wheel pant plate rotate tooling.jpg (74.17 KiB) Viewed 10205 times

[Sonex1243]

Thanks for the tips Bryan,

A slight diversion from the gear work. I needed to fabricate the battery box and dinked around with modifying the plans drawings as suggested in the Jabiru install guide to use piano hinging to facilitate removal of the battery when needed. After a few iterations, I settled for this one.


The battery will be modified by removing the side post option. You remove the post nut and cut the plastic rivet off.


Layout almost ready for bending. First attempt failed, I forgot to anneal the tabs before bending completely over. They cracked and one snapped off.

[Sonex1243]

I built up the brake caliper assemblies and greased the wheel bearings last night. They fit the backing plates pretty good, will need some tweaking to install on the axles. As Bryan pointed out, the backing plates need to be rotated for a conventional gear, they will stay like this for now and be redone later.

Today I started fabricating the brackets needed to mount the oil cooler to the engine. I finished the oil cooler bracket and have the left oil cooler support marked out for cutting, the right is made opposite of the left from the other angle blank.

[Sonex1243]

Brake assemblies were installed after the stop nuts Bryan suggested using arrived. A slight bevel on the washers did the trick. After installing the wheels, the brake pucks scrubbed heavily on the brake disk with the pistons fully bottomed. I may work them down on the belt sander just enough so they don't interfere and let the wheel spin freely when setting the final axle nut location.

Switched gears and modified the engine oil cooler and fabricated the support brackets. The battery box was finished, down to fabricating the hold down strap and piano hinge segments that will hold it to the firewall and allow easy removal for battery servicing.


Smaller stop nut and washer used to mount the brake and wheel pant backing plates.


Front lower flange removed and support brackets ready for install.


Final battery box fit.

[Bryan Cotton]

After installing the wheels, the brake pucks scrubbed heavily on the brake disk with the pistons fully bottomed. I may work them down on the belt sander just enough so they don't interfere and let the wheel spin freely when setting the final axle nut location.

I'd probably figure out some spacers to move the wheel out a little bit. You may need to do that at some point anyway. I have 2 on the outside of one wheel and 1 on the other. You can either use big washers of the right size or use a couple of holesaws to make your own washers out of aluminum. I've done both.

[Sonex1243]

I'm toying with the idea of cutting down the wheel spacers provided for the original azusa brake install, depends how well I can cut a thin 1/16" - 1/8" off with a hacksaw! I should probably save time and aggravation by matching up some thick washers..

Made some more progress over the weekend, finished the battery box and installed the hydraulic brake master cylinder and brake handle. Went ahead and set her down on the wheels for the first time.

Another big milestone is that my Jab 3300 I inquired/ordered in October 2022 arrived at Arion right after the new year, it has shipped and should be here the 25th. What a crazy story, went from a 2024 lead time to spring 2023 to the new year! Can't say enough good things about Arion and their support staff.

After the engine was ordered back in October, I began sourcing/ordering all the hardware and accessories needed for the install. I have also completed the oil cooler baffle upgrade and it is ready to install on the engine eventually.

[Sonex1243]

Exciting week, the Jabiru 3300 arrived from Arion Aircraft and is a thing of beauty! The engine was inspected and parts inventoried, everything was there. Since it will be in storage for a short time, I threw in a couple bags of desiccant and screwed the lid back on.

To celebrate, I mounted the air filter assembly to the aeroinjector.

[Sonex1243]

Work this weekend was focused on finishing the hydraulic brake upgrade. The brake lines were installed after drilling two exit holes in the firewall and routing each line to the brakes. Once I was happy with the routing, I added some chafe protection inside where feet will be and any close contact with the mount.

Since I removed the glareshield and instrument panel for better access while routing the brake lines, I went ahead and laid out the rudder cables and routed them through the fairleads to the tail.

Switched gears again and dug out the laser cut exhaust tunnels and marked them up for bending. The tunnels and deflector lips will have to be installed after the cowling is fit after the engine is installed. I also made a tool to bend attachment flanges on the tunnels out of a scrap phenolic block.

[Sonex1243]

Finished forming the cowling tunnels and deflectors. Switched gears back to engine install preps and mounted the gascolater with fittings.







Getting close to hanging the engine, still need to find a good location for the voltage regulator and start/contactor that came with the engine.