Turbo props running in feather before shutdown

[RightSeatGirl]

100's mostly, but hot starts due to a quick turn can happen on the 300 as well.

[smig]

But being a free power turbine, the engine temps don't really change with with prop in feather. The NH and ITT are about the same. That is the point that has me confused about this temp stabilization thing.

[bareman]

Originally Posted by smig

But being a free power turbine, the engine temps don't really change with with prop in feather. The NH and ITT are about the same. That is the point that has me confused about this temp stabilization thing.

You said the answer - Stabilization. I understand it to be primarily for cooling of bearings etc (not temps that you find on a gauge). You are not producing thrust which I suppose is good if you are parked at a gate. Realistically at idle with props unfeathered, it really doesn't matter though.

[FOD]

I remember the dash mx manual saying something about leaving them at start/feather for 30 seconds before shut down, so that you can get an adaquate oil check.

Also, know that if you dont wait the 30 seconds, the prop will be hard to spin by hand. Noticeable when spining the blades during preflight.

[SpiraMirabilis]

In Phoenix in the summer its not uncommon to have to wait till around 25% Nh to introduce fuel, or slightly higher than that. Usually I wait until the ITT is below 200' then introduce fuel.

[///AMG]

Originally Posted by Polar742

Free-power turbines, such as the PT-6 on the King Air and the GE on the SAAB, don't require that the prop turns in order to start the engine. So it's easier to let them bleed off to feather, or some procedures (I'm reaching way back) and systems are designed to place the prop to feather prior to shutdown. Usually bringing the condition levers to cutoff will feather the engine as it shuts down (I think this is the way it was in the King Airs - again, I'm reaching deep in the memory, so I could be completely off base)

Yes, this is correct WRT the PT6. On the -25A the prop will return to feather somewhere in the 10-12 psi oil pressure range, so as the engine is shut down by pulling the cond. lever back to FUEL-OFF, the prop will slowly return to feather as the oil comes back out of the hub and pitch-change assembly.