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912/4 Oil temperature rise from cold

in General Tech Discussion 13 years ago
I've just fitted a water/oil heat exchanger instead of the oil/air cooler.
On a 5°C day it took 4 mins 20 secs to get the oil from 5°C to 50°C with the engine running at about 2100 rpm.
The oil temperature follows the water temperature rise but lags about 3 to 4°C behind.
If you are like me and live in a cold climate I'd recommend this.
Mike G
Datasheet.pdf (You do not have access to download this file.)

  • Re: 912/4 Oil temperature rise from cold

    by » 11 years ago

    How does it work on very hot days ??? I live in northern BC and have trouble getting up to the recommended oil temp as i have a pusher with no cowling.
      
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  • Re: 912/4 Oil temperature rise from cold

    by » 11 years ago

    Hi Mike,
    Down in Arizona I just had a Zephyr aircraft with a heat exchanger and they were always way over temp this summer. They just removed it and put in the oil cooler. It will be interesting when your summer comes back around. I would love to know more about how it works out next summer. Keep us informed.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
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  • Re: 912/4 Oil temperature rise from cold

    by » 11 years ago

    The problem with a coolant/oil exchanger is you lose redundancy. For certification, one of the main reasons Rotax has air cooled cylinders is that in the event of a coolant loss is the engine will continue to make enough power to get you home (it will continue to run at up to 75% power for a long time, not so long at 100% so don't try and take off again).
    With a oil/coolant exchanger what will happen to the oil if you lose all your coolant?
      
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  • Re: 912/4 Oil temperature rise from cold

    by » 11 years ago

    To my knowledge Zephyr quit using them because of high temp issues in the warmer climates. They have gone back to the oil cooler.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report

  • Re: 912/4 Oil temperature rise from cold

    by » 11 years ago

    Bob's comment is very valid. I fly a pusher gyro and if I ever lose power for any reason landing in a field is not a big deal, but for those of you flying aircraft that prefer longer runways it's very valid and should be considered before making the change to an oil/water heat exchanger.

    My setup is with a 3-way thermostat (from a landrover, lightweight plastic) and it just keeps the water at 85°C and the oil at about 90°C on cold days regardless of outside temperature. I would like to get a hotter thermostat to get the oil up to 100°C but I haven't found one yet.
    My water radiator is a bit too small (my error when I purchased it) and on hot days (I fly in the north of France and a hot day for us is like 25°C) the temperature creeps up to about 110°C oil and 100°C water, depending on the load and airspeed. I usually fly very slow, (less than 110 k/h, 70 mph) because that's the great thing about gyros and as a result the rad doesn't get much air. I am thinking of moving to the south of France where a hot day is like 35 - 40°C and I'll have to fit a bigger radiator if I do.

    I cannot see how this doesn't work for any installation so long as the water radiator is sized to handle the heat load from BOTH the oil and water systems and of course the oil/water exchanger is the right size with the right orifice and installed in the right place in the water circuit. I've seen some pretty goofy installations of these things suggesting that some people really didn't know what they were doing.

    That being said If you're in a hot climate you may not need to add the thermostat and exchanger simply because you don't have to wait that long for the oil to get to 50°C. I fly often on 0°C days and without the thermostat and oil/water heat exchanger it took anything up to 10 minutes to warm up the engine.
    Mike G
      
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