X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from [65.54.169.61] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 862111 for flyrotary@lancaironline.net; Fri, 08 Apr 2005 15:19:02 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.54.169.61; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Fri, 8 Apr 2005 12:18:17 -0700 Message-ID: Received: from 4.174.3.22 by BAY3-DAV31.phx.gbl with DAV; Fri, 08 Apr 2005 19:18:17 +0000 X-Originating-IP: [4.174.3.22] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: idle speed with RD1 redrives? Date: Fri, 8 Apr 2005 15:18:14 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01C53C4E.2EE14CC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 Seal-Send-Time: Fri, 8 Apr 2005 15:18:14 -0400 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 X-OriginalArrivalTime: 08 Apr 2005 19:18:17.0633 (UTC) FILETIME=[B8057910:01C53C6F] This is a multi-part message in MIME format. ------=_NextPart_000_0010_01C53C4E.2EE14CC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I'm sure it does. I was, of necessity, generalizing. I mentally = compose words slowly and type (with two fingers) even slower. George = lurks on this list occasionally and lives in Sarasota. Tracy Wouldn't the moment of inertia of the prop be a significant factor? =20 Perhaps not since most props will fall into a small window in that = regard.=20 Where is George Graham? How would one get hold of him? ... Jim S. Tracy Crook wrote: > The torsional resonant point is highly dependant on how smoothly the = > engine idles. If you have no misfires, the RD-1C hits resonance at=20 > around 800 rpm. If you have any misses at idle, this immediately=20 > introduces a much higher amplitude and lower frequency excitation to = > the system and it will show up at a higher rpm. > =20 > In summary, the "rattle point" is more dependant on idle quality = than=20 > absolute rpm. Do not be too concerned about this however. It will = > cause no harm to the drive or engine. The drive has been torture=20 > tested for over an hour running on one rotor over the full range of=20 > throttle settings. If you've ever run a twin rotary on one rotor, = you=20 > know how violent this is. George Graham ran his Mazda transmission=20 > redrive on one rotor for about 2 seconds before every gear tooth on=20 > one gear was stripped off.=20 > =20 > Tracy (now canoeing to the post office one last time before=20 > departing for S'nF) > > > Greetings, > =20 > I asked this a couple times, but it was always buried at the end > of long messages, which gives me a clue how few people make it = to > the end of those :-) > =20 > IIRC, the RD1 drives have a low rpm point where they're known to > rattle. I guess this is torque reversals, or something like = that > from the engine. Anyway, can someone confirm that this is true, > and tell me what rpm this is supposed to happen at? I've never > been able to idle below 1500 or so, but now, I could probably = idle > down to 1000 easily. The problem is that I seem to hit this > rattle mode at 1100-1200 rpm, so I've got my idle set at 1400 = for > now.=20 > =20 > Thanks, > Rusty (wondering if I should have inspected the redrive = following > the oil out) > =20 > =20 > PS- TIG and Plasma machines both got 1.5 inches of water before = I > picked them up, but I dried them out yesterday, and they both = work > now (thank goodness). Fortunately nothing expensive was damaged > in the flood, assuming we don't have to replace the carpet in = the > great room. > >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0010_01C53C4E.2EE14CC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I'm sure it does.  I was, of necessity, generalizing.  I = mentally=20 compose words slowly and type (with two fingers) even slower.  = George lurks=20 on this list occasionally and lives in Sarasota.
 
Tracy

Wouldn't the moment of inertia of the prop be a = significant=20 factor? 
Perhaps not since most props will fall into a small = window=20 in that regard.
Where is George Graham?  How would one get = hold of=20 him? ... Jim S.

Tracy Crook wrote:

> The torsional = resonant=20 point is highly dependant on how smoothly the
> engine = idles.  If=20 you have no misfires, the RD-1C hits resonance at
> around 800=20 rpm.  If you have any misses at idle, this immediately
>=20 introduces a much higher amplitude and lower frequency excitation to =
>=20 the system and it will show up at a higher rpm.
> 
> = In=20 summary, the "rattle point" is more dependant on idle quality than =
>=20 absolute rpm.   Do not be too concerned about this = however.  It=20 will
> cause no harm to the drive or engine.  The drive = has been=20 torture
> tested for over an hour running on one rotor over the = full=20 range of
> throttle settings.  If you've ever run a twin = rotary on=20 one rotor, you
> know how violent this is.  George Graham = ran his=20 Mazda transmission
> redrive on one rotor for about 2 seconds = before=20 every gear tooth on
> one gear was stripped off.
>  =
> Tracy  (now canoeing to the post office one last time = before=20
> departing for = S'nF)
>
>
>    =20 Greetings,
>     =20
>     I asked this a couple times, but it = was=20 always buried at the end
>     of long = messages,=20 which gives me a clue how few people make it=20 to
>     the end of those=20 :-)
>      =
>    =20 IIRC, the RD1 drives have a low rpm point where they're known=20 to
>     rattle.  I guess this is = torque=20 reversals, or something like that
>     from = the=20 engine.  Anyway, can someone confirm that this is=20 true,
>     and tell me what rpm this is = supposed to=20 happen at?  I've never
>     been able = to idle=20 below 1500 or so, but now, I could probably=20 idle
>     down to 1000 easily.  The = problem is=20 that I seem to hit this
>     rattle mode at = 1100-1200 rpm, so I've got my idle set at 1400=20 for
>     now.=20
>      =
>    =20 Thanks,
>     Rusty (wondering if I should = have=20 inspected the redrive following
>     the = oil=20 out)
>     =20
>      =
>     PS-=20 TIG and Plasma machines both got 1.5 inches of water before=20 I
>     picked them up, but I dried them out = yesterday, and they both work
>     now = (thank=20 goodness).  Fortunately nothing expensive was=20 damaged
>     in the flood, assuming we = don't have=20 to replace the carpet in the
>     great=20 room.
>

>>  Homepage:  http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
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