atr: why is ITT limited in hotel mode

[stubby1]

hi
was thinking as to why is the ITT limited to 715 in hotel mode. otherwise it can go till 800.
If the prop not running & hence not cooling theory goes : this doesn't hold as with prop rotating, if ITT allowed is 800, so it means that this is the temp it can take. now if the prop was turning or not the temp should be limited to 800, ??????

It appears this may have something to do with the cooling of other parts ( gene, oil cooler etc)

am i missing something ?:hmm:

[Dufo]

Less mass flow perhaps, creating local hot spots? (ITT is not always the hottest temperature inside the engine)

[Papa2Charlie]

My guess would be that it's due to a lack of cooling flow for the air/oil cooler. Higher ITT's would result in more heat rejection to the oil and as there's limited cooling flow over the air/oil cooler, it could result in oil temperature getting unacceptably high.

P2C

[ImbracableCrunk]

How about cooling issues with a static power turbine section? That was the excuse I was given with CT-7s and the prop brake on the SF-340 as to why they were deactivated.

[no-hoper]

More than 700 in Hotel Mode means there is a problem.Idle ITT is below 400,each pack on full hot will give 140 on top.
Oil temp is no issue,old ATR have got a bleed driven venturi device to produce airflow through the oilcooler.Newer ones have a reverse intake airflow via the oilcooler in Hotel Mode.