912 Warm up

[Sporo]

I have a 912 ULS in my Savannah. The POH requires oil temp at 50 Celsius before taking full power for take off. On my gauges this takes forever say 5 to 10 mins. How long should it take before the motor is ready to go?

[James Bentley]

Yes, it does take at least 5 to 10 minutes and is dependant on the ambient temperature at start up

Winter at least 10 minutes and summer it is quicker to reach the 50 degree minimum

the reason for this recommendation is that at low oil temperatures it is still quite thick and with an increase in engine RPM the resulting high pressure will open the bypass valve and not all of the oil will be filtered

fitting a thermostat into the system will make a huge difference to the warm up time

[Morph]

Without an oil thermostat takes significantly longer. I typically would start up and as soon as the mgl gauge starts moving, usually at about 25 deg C I would start a nice slow taxi to the holding point. By the time I get there it is over 50 and ready for mag checks

[Sporo]

Thank you for your advice, much appreciated.

[Turbo]

What size oil cooler are you running?
What temperature does your oil run at once you are in the air on a hot day?

The reason I ask is because in my cheetah, the oil temps run around 80-90 deg C and rotax recommend 90-110deg C
Here's a quick fix for winter, if you don't have the time, money or ability to fit a thermostat. Block off 30% of the oil cooler fins with sticky Velcro tape. This will increase oil temps quicker and keep the operating oil temp higher to rid the oil of any moisture during operation.

A quick update on the boiling point of water at the reef, it boils at 94 degrees C on the ground, the higher you go, the lower the boiling point. It is bad to have you oil running too cold due to moisture build up. I blocked me rope 4 row on my oil cooler and the oil temps are now running at 100deg C. In summer i will remove the tape, but will install a thermostat for sure