New: Rotax/Sonex Cooling Kits Available!

[WaiexB22]

Will it fit a B model?

[Skippydiesel]

Rotax Installation Manual 912 Series, Chapter 79-00-00, Page 6

"When operating at low temperatures, installation of an oil thermostat, parallel to
the oil cooler is recommended."
"
NOTE: "...OPERATING IN LOW TEMPERATURE..."

Service Letter SL-912-011, SL-914-O09 Again this is a recommendation for low temperature operations.

I am unaware of what Rotax would consider LOW TEMPERATURE but would presume its where the operating oil temperatures can not be sustained above 90C.

Once again - While I can see the potential benefit in an oil thermostat, in particularly cold climate. They add significant weight & complexity, to the oil reticulation system, as such should be avoided.

With the exception of very cold weather operations, most Rotax can have temporary (winter) air flow restriction installed, using scrap aluminium/refrigerator/air conditioner tape or some other light weight/simple/low cost system.

[CaseyCooper]

Waiexb22, yes it does!

Skippy,

We can agree to disagree. Those 8 ounces or so are no worry to me. I eat and drink more than that at breakfast so I can afford it. Complexity consists of cutting your oil cooler in and out lines, then putting in your junction block known as an oil thermostat. Just a 15 minute job. I’m just speaking from my experience in the last 4 years and several hundreds of hours with that configuration in the Sonex.

While I do agree with you also, it’s definitely easy to tape up an oil cooler or something of the sort. But it makes a mess, you have to go up and test it. If it’s wrong, adjust it. Try it again. I would just rather it take care of itself and keep my temps up where they should be so I can get all the crud vented out of my oil.

While neither of us are right or wrong, we’ve demonstrated there’s a few different ways to skin a cat. Discussions like this are very constructive I find and give the community varying opinions on matters. That’s what makes aircraft, and most other things, fun!

[Skippydiesel]

Skippy,

Steve! A Rotax powered Sonerai is going to be a blast. I can’t wait to see how your project progresses.

Yep! A Rotax 912 ULS powered Soneri is indeed a "blast"

Check out:

http://worldrecordplane.com/
http://www.worldrecordplane.com/aircraf ... ment-story
https://www.homebuiltairplanes.com/foru ... -ii.34596/
https://en.wikipedia.org/wiki/Monnett_Sonerai
https://www.avcom.co.za/phpBB3/viewtopic.php?t=228964

[Skippydiesel]

Waiexb22, yes it does!

Skippy,

We can agree to disagree............................................................................................ That’s what makes aircraft, and most other things, fun!

I agree - the beauty of homebuilt/experimental aircraft is the pilot is free to customise his baby, any way he/she would like.

The experimentation required to know how much to reduce the airflow, is a once off , in that having found just the right amount of restriction, this can be applied every winter.

No one can refute the fact that the more connection points in a line (fuel/oil/coolant) the more potential failure points there are. Additional joins is often referred to a "complexity". In the sort of aircraft most Rotax 9's power - complexity is to be avoided/kept to a minimum.

As I said, if climatic considerations are such, that an oil thermostat should be fitted ($197-$418 US) fit one - go for it!

If you can get away with sheet of scrap aluminium, or a bit of tape, even better.

On my last 912ULS powered aircraft (900+ hrs/10+ years), I fitted a winter & summer fixed cowl (scrap aluminium) to the exit air. When temperatures dropped to consistently below 25C - I fitted the winter cowl. The summer, when temperatures rose again to consistently above 25C. Lightweight, minimal cost and zero additional complexity. Once made, took only 5 minutes to remove/reinstall. Worked a treat!

[Kai]

I seem to recall that once upon a time there were some employees in the draughting dept of a manufacturing company working for the government, that could not get to grips with persistent coolant losses on some prototypes. Some brighthead finally brought this to the attention of the director of engineering, a Mr Hives. Known for his fortright comments, he grumbled that we only had to make it as good as our toilets!

Surely, when having come to the conclusion that we are qualified to build our own planes, we should prosess the technical knowledge to make something as simple as a fuel- or cooling system leak proof?

[Skippydiesel]

Hi Kai,

"Surely, when having come to the conclusion that we are qualified to build our own planes, we should prosess the technical knowledge to make something as simple as a fuel- or cooling system leak proof?"

If humans can't prevent a leak in a technological marvel like rockets that go into space, it behoves us to keep all our systems (liquid & electrical) as simple (near fail safe) as the job we wish to acheive.

The more joins in a pipe the more chance of a leak - ego avoid joins, unless absolutely necessary.

There would be very few aircarft, operating in the Australian climatic conditions, that would achieve such benefit from an oil thermostat, so as to make the cash investment & additional risk (+ smidgeon of additional weight) worth while.

It seem to be part of human nature to be forever seeking to "enhance" a perfectly workable simple system. Sure if power/drag/safety is improved at a reasonable cost (may even achieve savings) without undue additional complexity - I am all for it.

For the most part Rotax powered aircraft are recreational/simple in nature - why change the tune???

[Murray Parr]

PS: I hope you're enjoying building some time in your Waiex Murray! That thing looks wonderful!

Thanks Casey!

Unfortunately, I haven't flown for the last couple of months. I had major surgery done on my hand and only just now getting enough use out of it to fly again. I used this time to completely rethink my cooling system and have started glassing in parts of the old system on the cowl.

I did some research on the 'Meredeth system' and after lots of measuring the radiator in position, I have now positioned the radiator on the lower cowl in its exact location so I can start designing a ducting system to suit. My early drawings came up with something similar to your system although I am tempted to start with a much smaller inlet and an adjustable outlet. Most likely, this smaller inlet could be perfect in flight but overheat on the ground, but I will try it first. Your system looks awesome, and I am sure it works awesome too! Probably would suit any other liquid cooled setup too and wouldn't need too much reshaping to suit different models/aircraft. Well done!

[WaiexB22]

Thanks Casey! Where can I get more dimensions and technical info?

I hope to see you at Oshkosh again this year.