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Date: Sat, 09 Feb 2008 15:23:28 -0700
From: Dale Rogers <dale.r@cox.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Rotor Weight Codes
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Umm, guys?  None of the above ... or both?

The rotor does in fact rotate around its own center, which is also the 
center of the eccentric (offset part of the shaft)

Since the eccentric shaft is also rotating, the center of the rotor is 
also in constant motion.  That is why the shape traced by the apex seals 
is called a "trochoid ".

Dale R.
COZY MkIV #0497
Ch. 13


Richard Sohn wrote:
> Sorry Al,
>
> I was not clear, certainly was meaning to say " around the e-shaft 
> lobe center, however, since the lobe center and the rotor center is 
> co-located with the lobe center, it does rotate around its own center, 
> or not?
> Tricky, isn't it.
>
> Richard Sohn
> N2071U
>
>
> ----- Original Message ----- From: "Al Gietzen" <ALVentures@cox.net>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Saturday, February 09, 2008 12:28 PM
> Subject: [FlyRotary] Re: Rotor Weight Codes
>
>
> the rotor is not sliding "back and forth" , it only makes a clean 
> circular
> motion around its own center. The weight only is significant for the
> centrifugal force on the e-shaft lobe.
>
> Richard;
>
> Unless I'm mistaken, or misunderstand what you're saying; the rotor 
> does not
> rotate around its own center.  And the CM of the rotor does not rotate
> around the center of the e-shaft, but rather follows the center of the
> e-shaft lobe.  Watch the animation on Tracy's web site.
>
> Al
>
>
> -- 
> Homepage:  http://www.flyrotary.com/
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>