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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.
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.
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.
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???
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???
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,
in the air as we "speak" 09:18 EDT August 28, 2020
NICE pic!
NICE pic!
Unkind folks used to say that the Shorts was "the box that the Dornier 328 came in!"
Love the fat boy short...looks like it just ate 3 little planes
The Skyvan can carry a vehicle driven up the rear ramp.
The Irish Concorde :)
ACTIVITY LOG
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Date | Aircraft | Origin | Destination | Departure | Arrival | Duration |
---|---|---|---|---|---|---|
30-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:47AM MST | 04:05AM MST | 0:18 |
29-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 06:20AM MST | 06:40AM MST | 0:19 |
29-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 05:54AM MST | 06:13AM MST | 0:19 |
29-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:47AM MST | 04:00AM MST | 0:12 |
29-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:27AM MST | 03:40AM MST | 0:12 |
28-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 05:36AM MST | 05:57AM MST | 0:21 |
28-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:34AM MST | 03:59AM MST (?) | 0:24 |
27-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 07:03AM MST | 07:25AM MST | 0:21 |
27-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 05:38AM MST | 05:59AM MST | 0:21 |
27-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 04:05AM MST | 04:22AM MST | 0:16 |
27-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:37AM MST | 04:05AM MST | 0:27 |
27-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 02:52AM MST | 03:13AM MST | 0:21 |
27-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 02:24AM MST | 02:52AM MST | 0:27 |
26-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 07:07AM MST | 07:49AM MST (?) | 0:42 |
26-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 05:58AM MST | 06:16AM MST | 0:17 |
26-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 04:34AM MST | 04:49AM MST | 0:14 |
26-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 04:13AM MST | 04:34AM MST | 0:21 |
26-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:30AM MST | 03:46AM MST | 0:15 |
26-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 03:04AM MST | 03:23AM MST | 0:18 |
23-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 08:34AM MST | 09:48AM MST | 1:14 |
23-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 06:13AM MST | 06:36AM MST | 0:23 |
23-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 05:35AM MST | 06:12AM MST | 0:36 |
22-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 07:12AM MST | 08:06AM MST | 0:53 |
22-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 06:08AM MST | 06:27AM MST | 0:19 |
22-May-2025 | Unknown | Coolidge Muni (P08) | Coolidge Muni (P08) | 05:33AM MST | 06:08AM MST | 0:34 |
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