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  #1  
Old 10-29-2022, 04:17 PM
Bill Whitefield Bill Whitefield is offline
 
Join Date: Jun 2021
Location: Houston
Posts: 18
Default Poor performance and possible prop connection

As part of the recent condition inspection of my RV-8A, the Whirlwind RV200 prop was sent back to Ohio for the 6 year tear down inspection. The plane performed the same as before the condition inspection for roughly 2-3 hours. On a recent local flight I noticed that the plane did not accelerate as normal, sluggish, on the take off roll and at 1,800 feet, 27 inches of manifold pressure, and 2500 RPM the plane was only indication 130 Knots. At this altitude and RPM it would normally take 19 inches of manifold pressure to get 135 Knots. In the pattern the plane was much slower for any combination of manifold pressure and RPM when compared to all previous flights. The prop does cycle properly and responds in flight as it is adjusted. Could have something happened with the prop to result in these performance changes? It was the only thing changed during the condition inspection.
Bill
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  #2  
Old 10-29-2022, 04:37 PM
rv8ch's Avatar
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 5,116
Default

What kind of engine and ignition? Do you have an engine monitor with data that you could potentially upload to savvyaviation.com? Might help identify the culprit.

Based on the information you have given, sounds like something with the fuel delivery or ignition, not the prop.
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  #3  
Old 10-29-2022, 06:49 PM
Chipper G Chipper G is offline
 
Join Date: May 2020
Location: Savannah GA
Posts: 147
Default

Quote:
Originally Posted by Bill Whitefield View Post
As part of the recent condition inspection of my RV-8A, the Whirlwind RV200 prop was sent back to Ohio for the 6 year tear down inspection. The plane performed the same as before the condition inspection for roughly 2-3 hours. On a recent local flight I noticed that the plane did not accelerate as normal, sluggish, on the take off roll and at 1,800 feet, 27 inches of manifold pressure, and 2500 RPM the plane was only indication 130 Knots. At this altitude and RPM it would normally take 19 inches of manifold pressure to get 135 Knots. In the pattern the plane was much slower for any combination of manifold pressure and RPM when compared to all previous flights. The prop does cycle properly and responds in flight as it is adjusted. Could have something happened with the prop to result in these performance changes? It was the only thing changed during the condition inspection.
Bill
I have a whirlwind prop on my mustang and there is a prop nut in the hub that adjust the pitch! Not sure on yours but call Jay and he can walk you thru it or shoot me a call and I can talk about it but the pitch needs to be set
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  #4  
Old 10-29-2022, 07:03 PM
Bill Whitefield Bill Whitefield is offline
 
Join Date: Jun 2021
Location: Houston
Posts: 18
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Who is Jay and how do I get hold of him?
Bill
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  #5  
Old 10-29-2022, 08:55 PM
Chipper G Chipper G is offline
 
Join Date: May 2020
Location: Savannah GA
Posts: 147
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Quote:
Originally Posted by Bill Whitefield View Post
Who is Jay and how do I get hold of him?
Bill
Jay is with whirlwind in Ohio. He is also the prop guy for my Mustang. Send me your number and e can chat tomorrow about it
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  #6  
Old 10-30-2022, 09:03 AM
lr172 lr172 is online now
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by Chipper G View Post
I have a whirlwind prop on my mustang and there is a prop nut in the hub that adjust the pitch! Not sure on yours but call Jay and he can walk you thru it or shoot me a call and I can talk about it but the pitch needs to be set
That nut DOES NOT adjust the pitch. The pitch is controlled via oil pressure sent from the prop governor. That nut simply sets either the min or max pitch that the blades can move to. Don't know WW props, so can't say which. The fine pitch stop is, generally speaking, never touched with the engine running in the air, except on initial TO roll and at very low power / speed, like in the pattern.

Larry
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Last edited by lr172 : 10-30-2022 at 09:14 AM.
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  #7  
Old 10-30-2022, 09:08 AM
lr172 lr172 is online now
 
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Not a lot in the prop to go wrong 3 hours after tear down to cause these symptoms and your description doesn't point to a prop issue. My guess is that it is coincidental and something in the engine has changed and now producing less power. Check compression, study both the fuel and ignition systems for problems. My guess is a fuel delivery issue or something killing compression.

Larry
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Last edited by lr172 : 10-30-2022 at 09:11 AM.
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  #8  
Old 10-30-2022, 10:12 PM
Chipper G Chipper G is offline
 
Join Date: May 2020
Location: Savannah GA
Posts: 147
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Quote:
Originally Posted by lr172 View Post
That nut DOES NOT adjust the pitch. The pitch is controlled via oil pressure sent from the prop governor. That nut simply sets either the min or max pitch that the blades can move to. Don't know WW props, so can't say which. The fine pitch stop is, generally speaking, never touched with the engine running in the air, except on initial TO roll and at very low power / speed, like in the pattern.

Larry
Yes it does. The prop nut up front sets initial pitch of the blades. I know this because my mustang after overhaul would not make power due to way to much pitch being dialed in at the prop shop. I understand how a cs prop works. You are corr3ct that oil pressure does it, however in this case he needs to adjust that nut and hub to set the proper pitch to start THUS THE NUT CONTROLS PITCH.
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  #9  
Old 10-30-2022, 10:14 PM
Chipper G Chipper G is offline
 
Join Date: May 2020
Location: Savannah GA
Posts: 147
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At least I would start there before I do anything. I have had this issue before and thatís what it was.
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  #10  
Old 10-31-2022, 09:02 AM
lr172 lr172 is online now
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 8,062
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Quote:
Originally Posted by Chipper G View Post
Yes it does. The prop nut up front sets initial pitch of the blades. I know this because my mustang after overhaul would not make power due to way to much pitch being dialed in at the prop shop. I understand how a cs prop works. You are corr3ct that oil pressure does it, however in this case he needs to adjust that nut and hub to set the proper pitch to start THUS THE NUT CONTROLS PITCH.
OP said it worked just as before for 3 hours then got worse. Are you suggesting that somewhere during this time the nut moved and changed the fine pitch stop to be too course?

FYI, words are important. The pitch stop adjustment DOES NOT set the prop pitch in flight nor does it set the initial pitch. It ONLY sets the maximum or minimum pitch angle that prop can be moved to by either the governor or the prop's internal springs. Yes, without governor involvement, the spring will be causing the pitch to be at the fine stops on a non-aerobatic prop and I am sure this is what you meant. I do agree that having the fine pitch set too course WILL prevent the governor from reaching it's RPM target and therefore see a reduced performance, but that does not appear to be the case for this poster as it performed as expected for 3 hours then changed.
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Last edited by lr172 : 10-31-2022 at 09:16 AM.
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