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haveblue1(at)mac.com
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 Posted: Tue Jun 28, 2011 5:55 pm Post subject: Prop pitch |
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Gary, and group,
As a fixed pitch propeller accrues hours, does the pitch stay the same? Or does it change based upon the propulsive load it generates?
Thanks.
Bruce Smith
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teamgrumman(at)yahoo.com
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| Posted: Tue Jun 28, 2011 6:49 pm Post subject: Prop pitch |
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Bruce,
That's a very good question. My opinion is that there is enough elasticity in the blade that it should not change pitch over time. That is just a guess.
Why? Do you have a prop with mixed pitches?
Gary
From: Bruce Smith <haveblue1(at)mac.com>
To: teamgrumman-list(at)matronics.com
Sent: Tue, June 28, 2011 6:52:23 PM
Subject: Prop pitch
[quote][b]
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haveblue1(at)mac.com
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| Posted: Wed Jun 29, 2011 3:02 am Post subject: Prop pitch |
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Gary,
No personal experience with this. It was a topic that came up over a fly-out dinner to Reading PA the other day. It seems that with all the load components (centrifugal and lift), the blades might change.
Bruce
On Jun 28, 2011, at 10:46 PM, Gary Vogt wrote:
| Quote: | Bruce,
That's a very good question. My opinion is that there is enough elasticity in the blade that it should not change pitch over time. That is just a guess.
Why? Do you have a prop with mixed pitches?
Gary
From: Bruce Smith <haveblue1(at)mac.com (haveblue1(at)mac.com)>
To: teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)
Sent: Tue, June 28, 2011 6:52:23 PM
Subject: Prop pitch
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href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/contribution
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michael(at)flightsked.com
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| Posted: Wed Jun 29, 2011 4:26 am Post subject: Prop pitch |
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Navy steam turbines exhibit something called blade creep - they will get longer over life due to the centrifugal force and thermal cycles they experience. However, those turbines are in continuous operation for long periods of time, we're talking about the fine tolerances of turbine assemblies, and it still takes a ship's lifetime to show up. The metallurgy's very different between steam turbine blades and our propeller blades, but I still kinda doubt it happens to a noticeable degree given the lack of a high temperature environment and relatively low duty cycle of our props.
Thanks,Michael
Michael W Meyer
michael(at)flightsked.com (michael(at)flightsked.com)
m: +1 781.248.7550
(sent from my iPhone, please excuse the brevity)
On Jun 29, 2011, at 3:59, Bruce Smith <haveblue1(at)mac.com (haveblue1(at)mac.com)> wrote:
[quote]Gary,
No personal experience with this. It was a topic that came up over a fly-out dinner to Reading PA the other day. It seems that with all the load components (centrifugal and lift), the blades might change.
Bruce
On Jun 28, 2011, at 10:46 PM, Gary Vogt wrote:
| Quote: | Bruce,
That's a very good question. My opinion is that there is enough elasticity in the blade that it should not change pitch over time. That is just a guess.
Why? Do you have a prop with mixed pitches?
Gary
From: Bruce Smith <[url=mailto:haveblue1(at)mac.com]haveblue1(at)mac.com (haveblue1(at)mac.com)[/url]>
To: [url=mailto:teamgrumman-list(at)matronics.com]teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)[/url]
Sent: Tue, June 28, 2011 6:52:23 PM
Subject: Prop pitch
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[b]
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teamgrumman(at)yahoo.com
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| Posted: Wed Jun 29, 2011 10:44 am Post subject: Prop pitch |
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Bruce,
I know they change in flight. I've seen high speed video of a prop in flight. Trust me, something you don't want to see. What I am not sure of is whether the prop takes a new set after repeated loadings. I'm calling my prop guy now. . . . . . . . . Mike says that the metal will relax some and flatten out the pitch over time but it is usually only a very small amount. Mike has been doing props for 30 years.
Gary
From: Bruce Smith <haveblue1(at)mac.com>
To: teamgrumman-list(at)matronics.com
Sent: Wed, June 29, 2011 3:59:12 AM
Subject: Re: Prop pitch
Gary,
No personal experience with this. It was a topic that came up over a fly-out dinner to Reading PA the other day. It seems that with all the load components (centrifugal and lift), the blades might change.
Bruce
On Jun 28, 2011, at 10:46 PM, Gary Vogt wrote:
[quote][b]
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teamgrumman(at)yahoo.com
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| Posted: Wed Jun 29, 2011 10:59 am Post subject: Prop pitch |
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Hi Mike,
Long time no see.
Talking about turbine blades . . . . while going to school at the Von Karman Institute for Fluid Dynamics in Belgium, we did flow visualization using fine dust particles, smoke, and lasers. We watched the flow separation and turbulence at the blade tips on a jet engine turning 10 to 10,000 rpms. It was pretty cool. I don't recall the gap to the wall but I know it was close.
So, Mike, How are things? Stop by some time and bring the Mrs.
Gary
From: Michael W. Meyer <michael(at)flightsked.com>
To: "teamgrumman-list(at)matronics.com" <teamgrumman-list(at)matronics.com>
Sent: Wed, June 29, 2011 5:23:16 AM
Subject: Re: Prop pitch
Navy steam turbines exhibit something called blade creep - they will get longer over life due to the centrifugal force and thermal cycles they experience. However, those turbines are in continuous operation for long periods of time, we're talking about the fine tolerances of turbine assemblies, and it still takes a ship's lifetime to show up. The metallurgy's very different between steam turbine blades and our propeller blades, but I still kinda doubt it happens to a noticeable degree given the lack of a high temperature environment and relatively low duty cycle of our props.
Thanks,Michael
Michael W Meyer
michael(at)flightsked.com (michael(at)flightsked.com)
m: +1 781.248.7550
(sent from my iPhone, please excuse the brevity)
On Jun 29, 2011, at 3:59, Bruce Smith <haveblue1(at)mac.com (haveblue1(at)mac.com)> wrote:
| Quote: | Gary,
No personal experience with this. It was a topic that came up over a fly-out dinner to Reading PA the other day. It seems that with all the load components (centrifugal and lift), the blades might change.
Bruce
On Jun 28, 2011, at 10:46 PM, Gary Vogt wrote:
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[quote][b]
| | - The Matronics TeamGrumman-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?TeamGrumman-List |
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michael(at)flightsked.com
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| Posted: Sun Jul 03, 2011 8:29 am Post subject: Prop pitch |
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Hi Gary,
That would be a really cool thing to see.
I'm doing well - Ali and I are in Kansas right now to see my family over the Fourth. Ali had never seen the grand canyon, so we flew over on one of the low-altitude sightseeing corridors.
Today looks like it's going to be the BBQ extravaganza - my brothers have been smoking all sorts if stuff the last few days.
What's new with you?
Thanks,Michael
Michael W Meyer
michael(at)flightsked.com (michael(at)flightsked.com)
m: +1 781.248.7550
(sent from my iPhone, please excuse the brevity)
On Jun 29, 2011, at 13:56, Gary Vogt <teamgrumman(at)yahoo.com (teamgrumman(at)yahoo.com)> wrote:
[quote]Hi Mike,
Long time no see.
Talking about turbine blades . . . . while going to school at the Von Karman Institute for Fluid Dynamics in Belgium, we did flow visualization using fine dust particles, smoke, and lasers. We watched the flow separation and turbulence at the blade tips on a jet engine turning 10 to 10,000 rpms. It was pretty cool. I don't recall the gap to the wall but I know it was close.
So, Mike, How are things? Stop by some time and bring the Mrs.
Gary
From: Michael W. Meyer <michael(at)flightsked.com (michael(at)flightsked.com)>
To: "teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)" <teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)>
Sent: Wed, June 29, 2011 5:23:16 AM
Subject: Re: TeamGrumman-List: Prop pitch
Navy steam turbines exhibit something called blade creep - they will get longer over life due to the centrifugal force and thermal cycles they experience. However, those turbines are in continuous operation for long periods of time, we're talking about the fine tolerances of turbine assemblies, and it still takes a ship's lifetime to show up. The metallurgy's very different between steam turbine blades and our propeller blades, but I still kinda doubt it happens to a noticeable degree given the lack of a high temperature environment and relatively low duty cycle of our props.
Thanks,Michael
Michael W Meyer
[url=mailto:michael(at)flightsked.com]michael(at)flightsked.com (michael(at)flightsked.com)[/url]
m: +1 781.248.7550
(sent from my iPhone, please excuse the brevity)
On Jun 29, 2011, at 3:59, Bruce Smith <[url=mailto:haveblue1(at)mac.com]haveblue1(at)mac.com (haveblue1(at)mac.com)[/url]> wrote:
| Quote: | Gary,
No personal experience with this. It was a topic that came up over a fly-out dinner to Reading PA the other day. It seems that with all the load components (centrifugal and lift), the blades might change.
Bruce
On Jun 28, 2011, at 10:46 PM, Gary Vogt wrote:
| Quote: | Bruce,
That's a very good question. My opinion is that there is enough elasticity in the blade that it should not change pitch over time. That is just a guess.
Why? Do you have a prop with mixed pitches?
Gary
From: Bruce Smith < (haveblue1(at)mac.com)[url=mailto:haveblue1(at)mac.com]haveblue1(at)mac.com (haveblue1(at)mac.com)[/url]>
To: (teamgrumman-list(at)matronics.com)[url=mailto:teamgrumman-list(at)matronics.com]teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)[/url]
Sent: Tue, June 28, 2011 6:52:23 PM
Subject: TeamGrumman-List: Prop pitch
|
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[b]
| | - The Matronics TeamGrumman-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?TeamGrumman-List |
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