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Water thermostat RV12iS

SH_Embedded_Wasser_Thermost.jpg



Yes, it would keep the coolant temp 80-85 C
 
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I believe Rotax chooses to not use T-stat in the cooling system as one less item that can fail...
 
I have a thermostat-mixer from Silent Hektik im my current plane and like it al lot. There is no warming up and always perfekt temps on oil and water. No problems in almost 200 hours.



So I will put it in my current built, the RV-12iS. It will go in the next week and I can post pictures and data if someone is interested.



https://www.silent-hektik.de/UL_912_Thermo.htm
 
There is no minimum coolant temp. The only reason I can think of for a coolant thermostat is if you want cabin heat from the coolant.
 
You should pretty regularly get over at least 212 F / 100 C for a period of time to drive the moisture out of your motor oil as a by product of combustion of gasoline.

Only the heads are liquid cooled on these engines. Oil temp would be the big concern.
 
There is no minimum coolant temp. The only reason I can think of for a coolant thermostat is if you want cabin heat from the coolant.

If you really want cabin heat, install the RV-12 Winterization Kit which consists of a sliding baffle for the water radiator and a selection of three different baffle plates to block off the oil cooler.
 
I have a thermostat-mixer from Silent Hektik im my current plane and like it al lot. There is no warming up and always perfekt temps on oil and water. No problems in almost 200 hours.



So I will put it in my current built, the RV-12iS. It will go in the next week and I can post pictures and data if someone is interested.



https://www.silent-hektik.de/UL_912_Thermo.htm

Yes, please, i‘m very much interested. Thank you.
 
You should pretty regularly get over at least 212 F / 100 C for a period of time to drive the moisture out of your motor oil as a by product of combustion of gasoline.

Not true.

Yes, it speeds up the process but moisture in the oil will be expelled at 185 degrees just as well as at 212 (especially at higher altitudes). It will just take a bit longer for any given amount.
 
I have a thermostat-mixer from Silent Hektik im my current plane and like it al lot. There is no warming up and always perfekt temps on oil and water. No problems in almost 200 hours.



So I will put it in my current built, the RV-12iS. It will go in the next week and I can post pictures and data if someone is interested.



https://www.silent-hektik.de/UL_912_Thermo.htm

There is a dramatic difference in cold weather warm up time between a 912ULS and a 912iS. The iS is much quicker.

Since the limiting factor is oil temp, not coolant temp., a coolant thermostat will have little influence on the operation of the engine.

Oil temp is limiting factor.
 
Not true.

Yes, it speeds up the process but moisture in the oil will be expelled at 185 degrees just as well as at 212 (especially at higher altitudes). It will just take a bit longer for any given amount.

I haven't forgotten my vapor pressure lessons of liquid to gas from chemistry.

The important part is that the temps are high enough to drive the moisture out of the motor oil, to prevent corrosion of internal parts, cams, followers, valve train, etc. Although I understand the bore of the Rotax is silica treated aluminum, as used on Porsche racing engines, for expansion contraction thermodynamic properties very close to that of the piston material, and not affected by corrosion from moisture in the motor oil. Which then allows very tight tolerances in the piston to bore measurements in the engine construction.
 
I asked about 912iS Vs. 912ULS oil warm-up time over in the RotaxOwner forum. If I get an answer I'll share soonest...
 
Bill Hertzel over in RotaxOwner Forum sent this...

Be sure you are comparing Apples...
The 912is installations may be more "Sophisticated."

My 912is has both an Oil Thermostat and a Coolant Thermostat.
It warms up quickly due to the fact that both coolant systems are essentially disabled by the thermostats until the temperature reaches 185°F.

If the ULS engine is installed with Open Loop Cooling, You will see slow warmups and owners taping over the radiators during cold weather in order to keep the engine from being Over-Cooled.

Contrary to common belief, the thermostat is Not there to keep the engine Cool, it is there to keep the engine HOT!
 
cooler question / real live temperatures RV-12iS

Like mentioned earlier I am intending to use a SilentHektik F1204 mixer thermostate with my 912iS. Yes I know the pros ans cons, but it workes like a charme in my Savannah-S. So I would like to have it in my RV too. The biggest hurdle is that the water cooler has to be able to take the additional load from the missing oil cooler. The original Rotax cooler can usually do this on most 912ULS instalations and if not the sport-cooler with 2 more rows will do. But no Rotax cooler will fit the RV-12iS. I just found out the left water outlet is interfeering with the exhaust pipe. The Vans cooler is coustom made and has both outlets on the south end of the cooler. Does anyone know if this cooler has enough reserve to take 25% extra load? How does it comparee to stock Rotax cooler? Real life climb out themperatures of a 912iS RV-12 could help calculate. The additional load should add about 35F. Any ideas?
 

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