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  #1  
Old 10-13-2021, 06:45 AM
Rich Pulman Rich Pulman is offline
 
Join Date: Oct 2018
Location: CYQA Canada
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Default Propeller orientation

Does it matter how a propeller is oriented when installed? I.E. with #1 cylinder at TDC, should the propeller be installed in the vertical, horizontal, or somewhere in between? I’m just wondering if there’s a “best practice” or recommended procedure out there. FWIW, I’m installing a WhirlWind GA200L on a Lycoming O290D2.

Any suggestions and/or anecdotes are much appreciated.
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  #2  
Old 10-13-2021, 06:55 AM
Jab Jab is offline
 
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Hi Rich

Yes, it does make a difference. See attached.

Gary

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  #3  
Old 10-13-2021, 07:05 AM
Freemasm Freemasm is offline
 
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In general, prop clocking matters; possible harmonics, torsional vibrations, etc.

The only opinion here that really matters is the prop OEMs. PP OEMs tend to be silent on said applications and I can't blame them.

Stay within your prop manufacturers recommendations. They may not have a restriction. Any anecdotal evidence by anyone else, "trouble free for xxx hours", should be ignored IMO. Potentially serious problems associated with the aforementioned probably won't give any indications of pending issues; i.e. it will probably reveal itself in very dramatic fashion. If you do consult the prop OEM, let us know what they say.
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  #4  
Old 10-13-2021, 07:25 AM
BillL BillL is offline
 
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Location: Central IL
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A two blade Hartzell should be aligned with the crank throws, at TDC it would be basically horizontal. The engine won't stop at TDC, but in-between anyway.

There are no hard rules, though, different props, # cylinders and measured vibration with mounts all have an influence on airframe vibration. The basic reason for the 4 cylinder is torsional and blade dynamics. A 6 is a different animal. Sometimes prop vibration is traded for airframe, but not without data.

An airplane in a 4-5 G arc will have the 2-blade alternate from a maximum and minimum mass inertia compared to the arc axis. Index with prop aligned with throws has the minimum inertia aligned with the firing pulse. Remember what happens when you try to rotate the axis of a spinning bicycle wheel? A composite like the WW will be minimal effects on the engine compared to aluminum or wood.

Top prop manufacturers work with engine manufacturers for their index recommendations. It appears WW has a locating lug per their instructions.
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  #5  
Old 10-13-2021, 08:42 AM
rmarshall234 rmarshall234 is offline
 
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As others have said, yes it does (or may) matter, find out what the manufacturer suggests.

Having said that, and more to your point...

The convention is to clock the prop at Ten / Two o'clock. 2 o'clock when viewed from the pilot seat and 10 o'clock if you are the guy "hand propping". Since you have a 2 bladed prop on an O-290, having it clocked properly for hand propping may come in really handy one day.
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  #6  
Old 10-13-2021, 08:47 AM
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Mel Mel is offline
 
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Default Clarification...

Quote:
Originally Posted by rmarshall234 View Post
As others have said, yes it does (or may) matter, find out what the manufacturer suggests.
Having said that, and more to your point...
The convention is to clock the prop at Ten / Two o'clock. 2 o'clock when viewed from the pilot seat and 10 o'clock if you are the guy "hand propping". Since you have a 2 bladed prop on an O-290, having it clocked properly for hand propping may come in really handy one day.
This orientation would be for the engine coming up on compression. Not TDC.
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  #7  
Old 10-13-2021, 08:47 AM
sjhurlbut sjhurlbut is offline
 
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Default Whirlwind

You installation manual for Whirlwind should say Cyl#1 TDC, prop as close to 10 o'clock. That what my 74HRT says. Won't necessarily shut down at this position.
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  #8  
Old 10-13-2021, 12:35 PM
Ralph Inkster Ralph Inkster is offline
 
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Your prop manufacturers instructions would be your first source for this.

It may or may not conflict with Lycoming SI 1098G. Caution- when reading this Lycoming document, note that they are not referring to a TDC position, but to the position of the #1 connecting rod bearing when describing prop bushings & clocking position.
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  #9  
Old 10-13-2021, 04:32 PM
blaplante blaplante is offline
 
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Another source of info -
I found that the Cessna 172 manuals describe how the prop is supposed to be clocked to the engine.
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  #10  
Old 10-14-2021, 01:13 AM
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rv8ch rv8ch is offline
 
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Lots of discussion on this on VAF over the years:

https://www.google.com/search?q=site...e.com+clocking

I didn't re-read the threads but IIRC, there were some that said they had good results by clocking in a non-standard way.
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