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Short Skyvan (N196WW) - Short visit to CYHU, 21-08-2020.
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Short Skyvan (N196WW)

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Short visit to CYHU, 21-08-2020.

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CHRIS ROBEY
Left prop is feathered which is unusual on the ground for a Garrett engined a/c. But the R/H prop is in the usual flat (very fine) pitch which reduces starting loads.
Chris, your photo and comment fascinate me and I have been trying to find an answer for years, which is, all turboprops I see when on the ground and starting up, all have their props pitched flat to the air as shown in the left prop, which I would gather would have the most air resistance which doesn't make sense to me.

You indicate and mention that such a flat pitched prop is unusual yet that is how I see them all, when parked and when starting up.

I am obviously not a pilot, but could you or someone explain why they are the way they are when I see them and I assume that is the correct way even though you say it is unusual.

Confused I am. ;-)

I would have thought being flat to the wind would provide a lot of wind resistance to the start-up and make it harder on the starter motors.
Champdriver
First off, Chris Robey is referring to the left engine, NOT the engine in the left side of the photo.
Garretts are normally shut down with the the prop blades in the flat or fine pitch setting.
Pratt and Whitney PT6's are shut down in the feathered setting. It has something to do with the different way they operate and whether it's a free shaft or something.
I only flew Pratts on the King Airs and never flew Garrett turboprops.
Apparently you can shut down a Garrett TPE331 either way though.
Thanks, Jim and I assumed the attention was given for the port (left) engine.

I am just curious why such turboprops always seem to be started up with the blades feathered flat to the wind, not just when shutting down, and doing that actually makes sense.

What doesn't make sense to me is having the blades feathered flat against the wind that would increase the spinning resistance. And is there any reason for doing so???

Or are the props just freewheeling during startup and there isn't any actual resistance on the starter motor engines involved???
CHRIS ROBEY
Hi Patrick. The Garrett TPE331 engines in this Skyvan are fixed shaft turboprops. So there is a direct physical connection between compressor section, turbine and propeller. So this will mean that the lowest starting load will occur with the blades in the normal (for a Garrett) fine pitch (like the actual R/H prop in this shot of N196WW). The PWC PT6A turboprop which is widely used (including on MOST, but not on all Beech King Airs) is a free turbine design where there is only a gas connection between the compressor section and the turbine section and the propeller. These blades normally start out slowly from the feathered position, which has the benefit of being safer for ground personnel.
Thanks, Chris and others, who supplied my brain with some more information it can use,
jesse kyzer
in the air as we "speak" 09:18 EDT August 28, 2020
NICE pic!
adelma
Unkind folks used to say that the Shorts was "the box that the Dornier 328 came in!"
garritt
Love the fat boy short...looks like it just ate 3 little planes

CHRIS ROBEY
The Skyvan can carry a vehicle driven up the rear ramp.
Bob Plested
The Irish Concorde :)
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1998년까지 거슬러 가는 N196WW에 대한 완전한 이력 검색을 원하십니까? 지금 구매하세요. 1시간 이내에 구하십시오.
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