SonexBuilders.net

Guys,

Thanks- excellent info: a lot to consider!

Two lever operated 1/2” Hegars, one master for each wheel caliper, seems an acceptable way to go. I am a little unsure if I should either adapt the long Sonex brake handle, or put in a complete Hegar setup. Your thoughts on this?

Thanks
Kai

Two lever operated 1/2” Hegars, one master for each wheel caliper, seems an acceptable way to go. I am a little unsure if I should either adapt the long Sonex brake handle, or put in a complete Hegar setup. Your thoughts on this?

Thanks
Kai

My thoughts would be to try them as supplied and if you need to change the handle geometry you can do that during testing.

Murray

Murray,

Duly noted: I guess I’ll have to start somewhere! I’ll order the setup from Hegar to set the wheels in motion. The installation will probably be a winter project- at least one wing will have to come off for access.

Thanks
Kai

Zack wrote:The larger spinner and redesigned cowling will really change the profile of the aircraft. Mace Aviation created a 7 page PDF slide show I can share with other views, but I'm not sure the best way to post it.

Here is the cowling attached.

Zack wrote:Here is the cowling attached.

This is the front view. Oil cooler up top and ducted radiator below.

That does it. I'm never posting a picture of my cowling :-)

Rusty (Frankencowl)

Zack wrote:

Zack wrote:The larger spinner and redesigned cowling will really change the profile of the aircraft. Mace Aviation created a 7 page PDF slide show I can share with other views, but I'm not sure the best way to post it.

Here is the cowling attached.

I am just at the stage of using;
The Sonex supplied vertical split cowling, suitably modified to fit my set up
OR
Making a cowling from scratch.

My Sonex has a Rotax 912 ULS driving an an Airmaster CS 3 blade prop (large spinner/back plate).
Coolant radiator is mounted just below lower firewall and will be cooled by cowling exit air - cowling will need to be a good fit to facilitate cooling system.
Oil cooler mounted directly behind right cowling inlet(may over cool)

Size of inlets will be critical to achieve adequate ground ops cooling while not creating undue drag in flight.

Any additional information you can supply will be very much appreciated

Skippydiesel wrote:I am just at the stage of using;
The Sonex supplied vertical split cowling, suitably modified to fit my set up
OR
Making a cowling from scratch.

My Sonex has a Rotax 912 ULS driving an an Airmaster CS 3 blade prop (large spinner/back plate).
Coolant radiator is mounted just below lower firewall and will be cooled by cowling exit air - cowling will need to be a good fit to facilitate cooling system.
Oil cooler mounted directly behind right cowling inlet(may over cool)

Size of inlets will be critical to achieve adequate ground ops cooling while not creating undue drag in flight.

Any additional information you can supply will be very much appreciated

This cowling is for a 13" spinner with a 1.5" distance to flange. The airmaster AP332CTF-WWR64W (if that's what you're using) can use spinners of the following sizes according to the website: 8.3, 9.0, 9.5, 10.3, 11.2, 12.2, 13.0in. I don't know the distance to flange of the airmaster, but with spacers you should be able to fit this engine / prop / spinner combination without modification.

I'm having the exhaust fabricated next week. The bed mount will make this challenging and I haven't selected a design yet. 2-1 out the sides, 4-1 or 4-2-1 out the bottom will be largely determined by available space. I'm working with a motorcycle exhaust fabricator and will use in-line mufflers instead of the standard Rotax log muffler. I'll provide another update on this in a few weeks.

The oil cooler is mounted just under the propeller and will create positive cowling pressure.

The radiator is inside, with two ducts to keep airflow separate from the air inside the cowling. This will be neutral to cowling pressure. I will tune the outlet size to give the necessary cooling without added drag.

The front air inlets and oil cooler will be vented using the stock Sonex side vents. Since the radiator airflow is self contained, I will undersize these side vents so I don't have excess drag.

I spoke to Mark and Sonex is planning a split radiator Rotax installation using the side vents to draw air through. They mentioned they are considering blisters to add to the universal cowl to accommodate the Rotax installations. My large 13" spinner would require moving the inlets in the front further to the sides. I didn't want to do all the custom work required for the spinner, oil cooler and radiator so I started from scratch.

Great stuff Zack. Thanks for all that. Did you manage to work out how to post the pdf file you referred to??

Getting closer... I moved the 912UL Onex to the hangar today (finally). I just got the last part for the prop installation today, and the engine just needs fuel and a turn of the key aside from that. I hate the cold, so realistically, it won't be ready to fly until early spring.

Rusty