Return-Path: Received: from mail.zutrasoft.com ([66.11.174.123] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2944258 for flyrotary@lancaironline.net; Thu, 22 Jan 2004 14:29:42 -0500 Subject: RE: [FlyRotary] Re: Torsionals Date: Thu, 22 Jan 2004 14:28:38 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C3E11D.EF6C5B80" Message-ID: <9F7CCD5AA88D1B46A911658D80F960B805510F@zserver2.Zutrasoft1.zutrasoft.com> X-MimeOLE: Produced By Microsoft Exchange V6.0.6375.0 X-MS-Has-Attach: X-MS-TNEF-Correlator: content-class: urn:content-classes:message Thread-Topic: [FlyRotary] Re: Torsionals Thread-Index: AcPhGxtlc25MPPmOShOpE+zhGTYWPAAAhoOA From: "Peter Zutrauen" To: "Rotary motors in aircraft" This is a multi-part message in MIME format. ------_=_NextPart_001_01C3E11D.EF6C5B80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable From what I understand, in addition to lowering the resonant frequency = it would also dissipate some of the resonant energy through flex-induced = heating - thus damping the system somewhat.... Exactly what one would = want (verses springs which dissipate very little). Other damping schemes = which I have heard of include both springs and hydraulic damping in = combination. =20 Cheers, Pete Europa builder and single rotor dreamer. =20 =20 PS- anyone out there care to comment on my previous question of whether = single-rotors do indeed experience torque reversals? =20 =20 -----Original Message----- From: Jim Sower [mailto:canarder@frontiernet.net]=20 Sent: Thursday, January 22, 2004 2:09 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Torsionals =20 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.?=20 Lookin' for easy answers to hard questions again? :o) .... Jim S.=20 Al Gietzen wrote:=20 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 - =BD = 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 ------_=_NextPart_001_01C3E11D.EF6C5B80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

From what I understand, in addition = to lowering the resonant frequency it would also dissipate some of the = resonant energy through flex-induced heating – thus damping the system = somewhat…. Exactly what one would want (verses springs which dissipate very little). Other = damping schemes which I have heard of include both springs and hydraulic damping = in combination.

Cheers,

=

Pete

Eur= opa builder and single rotor = dreamer.

PS- anyone out there care to = comment on my previous question of whether single-rotors do indeed experience torque reversals?

-----Original = Message-----
From: Jim Sower [mailto:canarder@frontiernet.net]
Sent: Thursday, January 22, 2004 = 2:09 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: Torsionals

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 – =BD 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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