Engine operational limits on hot/cold days

[pilot9248]

Hi,

I know this is a basic question. I'd just like to make sure I have understood everything correctly.
When operating a gas turbine engine on a cold day (e.g. -5 °C OAT), max thrust/torque is limited by max shaft rpm with respect to material strength withstanding the centrifugal forces.
On a hot day (e.g. 30 °C OAT), the limiting factor is either max EGT, ITT, or TGT, depending on the specific temperature monitoring system installed on the engine. As long as this temperature stays below the specified design limit, the turbine blades and nozzle guide vanes will stay intact.
Is this correct?

[de facto]

Sounds pretty convincing to me:)
TREF for a jet engine comes to mind where available thrust decrease with an increase of temp.

[pilot9248]

Cheers mate!
You're right about TREF, though I meant to focus on mechanical and thermal loads as a limiting factor.

[Old Fella]

Maybe I don't understand where you are going with the original question, but in terms of operational power limitations I have not seen a difference in allowable RPM's based on ambient temperatures. Published RPM limits, EGT limits, EPR limits etc are all the same regardless of the ambient temperature as far as I recall. Thrust/RPM limits apply in respect to lubricating oil temperature in some cases but that is not only applicable to turbine engines.

[pilot9248]

Fella,
You're right, the limits do stay the same regardless of the outside air temperature. Though my original question was which limit will be reached first, with respect to OAT.

[Old Fella]

Operating a gas turbine engine, whether it be a turbo-prop or turbo-jet engine, it is usual that in colder temperatures the maximum torque (turbo-prop) or thrust, say EPR, in the turbo-jet will be achieved before the limiting TIT or EGT is reached. On a Flat rated engine temperatures below, say 30 degrees C, will enable the engine to reach a limiting thrust figure before limiting EGT whereas in temperatures above 30 degrees C it is likely that the limiting EGT will be reached before the limiting thrust. At least that is my experience. Of course RPM limits also have to be observed.

[pilot9248]

Thank you. I guess our points are congruent.