Return-Path: Received: from relay03.roc.ny.frontiernet.net ([66.133.131.36] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2944223 for flyrotary@lancaironline.net; Thu, 22 Jan 2004 14:08:12 -0500 Received: (qmail 27573 invoked from network); 22 Jan 2004 19:08:11 -0000 Received: from unknown (HELO frontiernet.net) ([170.215.102.232]) (envelope-sender ) by relay03.roc.ny.frontiernet.net (FrontierMTA 2.3.6) with SMTP for ; 22 Jan 2004 19:08:11 -0000 Message-ID: <40101FCB.A1DE577D@frontiernet.net> Date: Thu, 22 Jan 2004 13:09:00 -0600 From: Jim Sower X-Mailer: Mozilla 4.77 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Torsionals References: Content-Type: multipart/alternative; boundary="------------6691E181A8FACAAAA4BA5694" --------------6691E181A8FACAAAA4BA5694 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit OK. So Tracy's re-drive is loose. Would not rubber bushings make it MORE loose? Or would that turn on more complex considerations such as the elasticity of the rubber, etc.? Lookin' for easy answers to hard questions again? :o) .... Jim S. Al Gietzen wrote: > I realize that these are relative terms, but my opinion is > that Tracy’s re-drive would not be called “tight” tolerance. > There is; what – ˝ back and forth play at the prop tip? As I > recall, Tracy had given this some consideration, and chose to > keep the relatively “loose” tolerance. > Subject: [FlyRotary] Re: Torsionals > Ed, > Assuming (key word here) that Tracy's PSRU can be regarded as > "tighter > tolerances", mightn't rubber bushings effectively "loosen" the > tolerances and > get us INto more trouble than they get us OUT of? > Just wonderin' .... Jim S. > Ed Anderson wrote: > > Hi Greg, > > > > Welcome to the list. > > > > Torsional vibrations and resonance are a fairly complex > topic. .. In > > generally tighter tolerances raises the resonant frequency > of an assembly > > and looser tolerances lower it. Tighter tolerances are > generally more > > expensive than looser. ...By the way, since the rotary does > not have a > > negative torque region in its > > power curve this problem is minimal and can generally be > handled by some > > simple dampeners such as rubber disks, etc. > > > > Ed Anderson > --------------6691E181A8FACAAAA4BA5694 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit OK.  So Tracy's re-drive is loose.  Would not rubber bushings make it MORE loose?  Or would that turn on more complex considerations such as the elasticity of the rubber, etc.?
Lookin' for easy answers to hard questions again? :o) .... Jim S.

Al Gietzen wrote:

I realize that these are relative terms, but my opinion is that Tracy’s re-drive would not be called “tight” tolerance.  There is; what – ½ back and forth play at the prop tip?  As I recall, Tracy had given this some consideration, and chose to keep the relatively “loose” tolerance.
Subject: [FlyRotary] Re: Torsionals
Ed,
Assuming (key word here) that Tracy's PSRU can be regarded as "tighter
tolerances", mightn't rubber bushings effectively "loosen" the tolerances and
get us INto more trouble than they get us OUT of?
Just wonderin' .... Jim S.
Ed Anderson wrote:
> Hi Greg,
>
>    Welcome to the list.
>
>  Torsional vibrations and resonance are a fairly complex topic.  ..  In
> generally tighter tolerances raises the resonant frequency of an assembly
> and looser tolerances lower it.  Tighter tolerances are generally more
> expensive than looser.  ...By the way, since the rotary does not have a
> negative torque region in its
> power curve this problem is minimal and can generally be handled by some
> simple dampeners such as rubber disks, etc.
>
> Ed Anderson
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