Mailing List lml@lancaironline.net Message #55998
From: <Sky2high@aol.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Prop Balance
Date: Thu, 12 Aug 2010 22:54:41 -0400
To: <lml@lancaironline.net>
Wolfgang,
 
The harmonic damper you refer to (12 pounds, bolts to Lyc flywheel) contains a steel ring in viscous silicone.  Its purpose is to dampen negative torque pulses and to provide for more flywheel momentum.  It is especially effective for light wooden props (rpm increase of approximately 100) but also serves it purpose with CS props even though the result appears to be un-measurable.   Review the torsional effects of a 4 cylinder engine here:  
 
 
It contributes nothing to dynamic prop balance :-( 
 
Grayhawk
 
In a message dated 8/12/2010 3:45:09 P.M. Central Daylight Time, Wolfgang@MiCom.net writes:
Or put a silicon filled balance ring at the prop hub :-)
 
Wolfgang

From: "Kent" <kent@tulsaconnect.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Prop Balance
Date: Thu, 12 Aug 2010 14:28:09 -0400
To: lml@lancaironline.net
Vibration sensor is placed on engine to measure how engine is moving in space.
Prop imbalance will make engine move in bigger circle.
So mayny Millivolts are genrated per vibration severity.

Relative location of heavy spot is  signaled by photo cell, or strobe light flash as heavy spot passes and polarity changes.  Up-down = plus-minus.

The prop's static weigh slugs can be adjusted or large area washers can be bolted to spinner bulkhead to counterbalance the heavy spot.

How much depends weigh depends on how much imbalance there was to begin with.

Common to have 10-30 grams of weight for a momento of 100-200 inch pounds.


Kent Felkins
Tulsa Oklahoma

----- Original Message ----- From: "Greenbacks, UnLtd." <N4ZQ@comcast.net>
To: <lml@lancaironline.net>
Sent: Thursday, August 12, 2010 7:20 AM
Subject: [LML] Re: Prop Balance


Could one of you describe the process of dynamically balancing a
typical prop?
My old brain cannot visualize how weights are attached.

Angier Ames
N4ZQ

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