X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from access.aic-fl.com ([204.49.76.2] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 972880 for flyrotary@lancaironline.net; Mon, 06 Feb 2006 19:10:16 -0500 Received-SPF: none receiver=logan.com; client-ip=204.49.76.2; envelope-from=unicorn@gdsys.net Received: from b9k4u9 (unverified [204.49.76.30]) by access.aic-fl.com (Rockliffe SMTPRA 4.5.6) with SMTP id for ; Mon, 6 Feb 2006 18:07:57 -0600 Message-ID: <001001c62b8c$77ac6380$1e4c31cc@b9k4u9> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Single rotor smooth as silk now Date: Mon, 6 Feb 2006 18:15:27 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01C62B49.4E976730" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C62B49.4E976730 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Monday, February 06, 2006 8:52 AM Subject: [FlyRotary] Re: Single rotor smooth as silk now Would a single with no dampers put the resonance beyond the useful range? Good question Ernest. I thought about trying the RD-1C drive with a = solid plug where the rubber dampeners normally live, but when I = considered that all the normal gear lash play would still be there, I = realized it was probably not going to be much of a test. =20 How much gear lash is there on a typical Hirth, or Rotax gear box? =20 Cheers, Rusty=20 There are two issues to cope with, one is resonances and the other is = transferring the torque pulses. The torque pulses are transferred = completely in a indefinitly stiff system. We do not want that, because = of the internal forces involved. That leaves the resonances created by = coupling and element flexing properties. I believe the only way to stay = out of the resonances is to keep them low. This is what ROTAX is doing, = a 582 has gear rattling around idle. When you watch a ROTAX starting up = it is very obvious when the rattling occurs. I have not observed any = rattle on my C-Box with the SOOB. My ROTAX C box has about 1/8" gear lash at the tip of th 72" prop. I = have seen the same on others, seems to be normal. Richard Sohn N-2071U =20 ------=_NextPart_000_000D_01C62B49.4E976730 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Monday, February 06, 2006 = 8:52=20 AM
Subject: [FlyRotary] Re: Single = rotor=20 smooth as silk now

Would a single with no dampers put the = resonance
beyond the=20 useful range?

Good=20 question Ernest.  I thought about trying the RD-1C drive = with a=20 solid plug where the rubber dampeners normally live, but when I = considered=20 that all the normal gear lash play would still be there, I = realized it=20 was probably not going to be much of a test.  =
 
How much gear lash is there on = a typical=20 Hirth, or Rotax gear box? 
 
Cheers,
Rusty
 
 

There are two issues to cope with, one is = resonances and=20 the other is transferring the torque pulses. The torque pulses are = transferred=20 completely in a indefinitly stiff system. We do not want that, because = of the=20 internal forces involved. That leaves the resonances created by = coupling and=20 element flexing properties. I believe the only way to stay out of the=20 resonances is to keep them low. This is what ROTAX is doing, a 582 has = gear=20 rattling around idle. When you watch a ROTAX starting up it is very = obvious=20 when the rattling occurs. I have not observed any rattle on my C-Box = with the=20 SOOB.

My ROTAX C box has about 1/8" gear = lash at the tip=20 of th 72" prop. I have seen the same on others, seems to be=20 normal.
 
Richard Sohn
N-2071U
 
 
 
 



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