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Re: FW: Crankshafts

To: tstrange@sbcglobal.net, sbarr@mccarty-law.com, jerrybarr@charter.net
Subject: Re: FW: Crankshafts
From: Fubog1@aol.com
Date: Wed, 19 May 2004 18:21:08 EDT
In a message dated 5/19/2004 12:25:47 PM Pacific Daylight Time, 
tstrange@sbcglobal.net writes:


> "Barr, Scott" <sbarr@mccarty-law.com> wrote:
> << You can tell that by actually measuring piston travel vs crank rotation. 
> It's pretty lazy up to about 90 degrees up the bore, then really speeds up. >>
> 
> Isn't this the opposite of what you'd expect? I would think that the up/down 
> piston travel would actually DECREASE in speed at the top and bottom of the 
> stroke as the rotation of the crank is more sideways (in cross-section) than 
> up and down. I would assume that the highest piston speed would occur where 
> the crank throw is at 90 degrees and 270 degrees from TDC. Am I wrong about 
> that?
> 
> 

If you look at the distance that the piston travels in the top half of the 
stroke, compared to the bottom half, it is much greater on the top. It has to 
accelerate/decelerate the reciprocating mass more distance for a given amount 
of 
crank rotation. This translates into more inertia load.
Glen

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