Rotax 912ULS Static Run Temperatures

by Denis Ranque in General Tech Discussion 10 years ago

Hi,

I was wondering if the cooling system of the rotax 912ULS is capable of maintaining operating temperatures during a high rpm static run?
My engine reaches CHT of 120 degrees celsius at 4000rpm static, and it exceeds the limit of 135 degrees celsius at 5000rpm static. :ohmy:

Is that normal?

Thanks in advance for the answers :)

Denis

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Re: Rotax 912ULS Static Run Temperatures

by Roger Lee » 10 years ago

Roger Lee

126 5.14k 4.61k

Hi Denis,

I could be normal depending on the engine and cowl setup and the OAT.

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

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Re: Rotax 912ULS Static Run Temperatures

by Denis Ranque » 10 years ago

Denis Ranque

5 12 1

Hi Denis,

I could be normal depending on the engine and cowl setup and the OAT.

Hi Roger,
The OAT was of about 28C, and here is a pic of the cowlin:

I am worried that the engine could overheat on climbout.

Photo0070.jpg (You do not have access to download this file.)

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Re: Rotax 912ULS Static Run Temperatures

by Roger Lee » 10 years ago

Roger Lee

126 5.14k 4.61k

Hi Denis,

Climb out temps should be different because hopefully you have good air flow through the system. If you just sit on the ground the engine will continue to heat because there is no air being forced over the engine and through the oil and coolant radiators.

28C (83F) and just sitting static on the ground could get temps fairly high depending on rpm and length of run time. Removing the cowling during a static long run can help reduce some of those temps.

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

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Re: Rotax 912ULS Static Run Temperatures

by Denis Ranque » 10 years ago

Denis Ranque

5 12 1

Roger, thanks for your answers.

It is comforting to ear that this behavior could be normal.
I was assuming (wrongly) that the propeller would produce sufficient airflow to cool the engine.

And also, I heard that you can know a lot about the performance of the engine trough the EGT's.
I can only know if they are within operating range. :unsure:
I ask that because the EGT's of my engine (read on the tow rear cylinders) sometime have a difference of 50 degrees Celsius. How synchronized should the EGT's be?

Regards

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Re: Rotax 912ULS Static Run Temperatures

by Roger Lee » 10 years ago

Roger Lee

126 5.14k 4.61k

First carbs should be synced and provided everything else is normal, EGT temps and temp differential between EGT's will differ with throttle settings. They may be 5F apart or upwards to 100F. Normal can be 10F-80F depending on the throttle, plugs and carb balance. There are a few other factors, but we are considering that there are no other problems.

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

Report

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