New: Rotax/Sonex Cooling Kits Available!
Posted: Fri Jul 12, 2024 12:38 am
by Skippydiesel
The new system looks great BUT seems only to address half (Coolant) the liquid cooling requirement.
Where is the oil cooler? - hidden in the ducting? or somewhere else entirely?
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Fri Jul 12, 2024 1:07 am
by Murray Parr
The oil cooler looks to be in front of the coolant radiator, I wonder if you could put the oil cooler behind instead. My oil takes forever to heat up enough for takeoff but the coolant quickly overheats and could possibly help speed up warming the oil. Maybe they tested this already or maybe not.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Fri Jul 12, 2024 3:55 am
by Skippydiesel
Ahhh I should have looked further at the additional photos.
Oil cooler appears to be where you found it. It wouldn’t be hard to fit a small, pilot condoled, flap/shutter to the exit air - that would certainly speed the warm up.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Fri Jul 12, 2024 11:36 am
by ampzapper
Their full install kit includes an oil thermostat. That could help with warmup.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Fri Jul 12, 2024 6:10 pm
by Skippydiesel
ampzapper wrote:Their full install kit includes an oil thermostat. That could help with warmup.
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.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 1:02 am
by CaseyCooper
Hello folks,
The cooling assembly houses both the oil cooler and radiator. The thermostat opens at 180f and weighs about 8 ounces. When warming up my engine, whether summer or winter, it takes exactly 5 minutes on the dot to achieve operating temperature. With a peak oil pressure of 70 psi while the valve is restricted and bypassed (it allows 10% of the oil to flow through oil cooler until warmed up and the rest to flow through the engine normally) and a minimum oil pressure of 55 psi, the system works perfectly within Rotax’s specifications. While you could add a manual baffle of some kind, a thermostat is automatic, recommended by Rotax, less complex, and the same weight if you were to design such an assembly. While flying just this evening with 105 degrees OAT, I was seeing max temps of 225 for CHT’s and 210 OT. With hundreds of hours on this combination, I have complete faith in the system.
We’re gearing up for our 4th trip to Airventure this year and looking forward to seeing everyone there!
PS: I hope you’re enjoying building some time in your Waiex Murray! That thing looks wonderful!
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 2:33 am
by Skippydiesel
Hi Cadey,
“…a thermostat is automatic, recommended by Rotax,”
Please give me the Rotax manual/chapter/page where Rotax recomend the installation of an oil thermostat?
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 2:34 am
by Skippydiesel
Hi Casey,
“…a thermostat is automatic, recommended by Rotax,”
Please give me the Rotax manual/chapter/page where Rotax recomend the installation of an oil thermostat?
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 3:38 am
by sonex892.
Skippydiesel wrote:Hi Casey,
“…a thermostat is automatic, recommended by Rotax,”
Please give me the Rotax manual/chapter/page where Rotax recomend the installation of an oil thermostat?
I found it recommended in the 214 page rotax install manual. Its at page 184.
I’m going through all this at the moment trying to fit radiator, oil cooler etc in a sonerai.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 1:44 pm
by CaseyCooper
Skippy,
Steve beat me to it! There’s some fine print to it but SL912-011 will help clear things up.
Steve! A Rotax powered Sonerai is going to be a blast. I can’t wait to see how your project progresses.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 5:26 pm
by WaiexB22
Will it fit a B model?
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 7:21 pm
by 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.
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 8:06 pm
by 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!
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 8:13 pm
by Skippydiesel
CaseyCooper wrote: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
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sat Jul 13, 2024 8:39 pm
by Skippydiesel
CaseyCooper wrote: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!
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sun Jul 14, 2024 2:09 am
by 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?
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Sun Jul 14, 2024 3:47 am
by 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???
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Mon Jul 15, 2024 4:44 pm
by Murray Parr
CaseyCooper wrote:
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!
Re: New: Rotax/Sonex Cooling Kits Available!
Posted: Tue Jul 16, 2024 4:29 pm
by WaiexB22
Thanks Casey! Where can I get more dimensions and technical info?
I hope to see you at Oshkosh again this year.