PT6 question

[Nolife]

I've heard from various sources that it bad to start a PT6 in feather. Wondering why? No one seems to have a good answer. Since it's a free turbine how would doing so affect the compressor section?

 

[dougdrvr]

I've heard from various sources that it bad to start a PT6 in feather. Wondering why? No one seems to have a good answer. Since it's a free turbine how would doing so affect the compressor section?

Long time since I've flown behind a PT-6 but we always feathered them on shutdown so you would have to start them that way. I've even started one with a mech holding on to the prop. Are you sure you don't mean the Garrett, 'cause starting them in feather or if they slip off the start locks will definately burn one up.

 

[Nolife]

Feather the pt6 on shut down so the blades stop spinning faster. Conventional start is with props forward and they come out of feather quickly. The only book procedure for starting in feather is when using a GPU, but the question remains... why is it bad to battery start with props feathered when you have a free turbine.

 

[twikysmalls]

Start the 67R every time in feather. Only comes out when ready for taxi, and feathered prior to fuel cutoff.

In fact, I have read quite possibly on this board, that it is bad to start a free turbine out of feather. Doing so would unnecessarily pull oil out of the engine needed for starting into the prop hub.

Perhaps an experienced mechanic could confirm or deny, as I am merely a dumb pilot.

 

[Cardinal]

With the prop levers forward for start, the propellor wont aggressively begin to move out of feather until 40-50% N1 anyway, I'd hope there's plenty of oil pressure/volume by then to multitask. But who knows, certainly not me.

 

[deadstick]

Any KA drivers need to get The King Air Book by Tom Clements. It's priceless. He has over 15,000 in the series and use to work for Beech.

I went checking for the answer. He states that it is no problem starting in feather, but you don't want to idle like that for a long time. The exhaust and heat are not getting dissipated. In the big models, this delay can pose a problem because the blades are pushing that hot exhaust up against the fuselage and the plastic windows.

 

[Nolife]

Thx for the post. I'm going to look for that book.

 

[avbug]

Starting the engine with the propeller controls in feather isn't going to hurt a thing.

 

[A&PMECH]

Hi guys,

 

[skysurfer76]

i second the thought on the heat on the plastic D windows when starting in feather....I have noticed the OAT gauge that sits right below the captains D window will be pegged out with a left cross wind start in feather....the exhaust gas drifts right onto the cabin while in feather....I have heard of it actually melting or disdorting those windows as well..

just my .02 : )