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 973084 for flyrotary@lancaironline.net; Mon, 06 Feb 2006 23:00:54 -0500 Received-SPF: none receiver=logan.com; client-ip=204.49.76.2; envelope-from=unicorn@gdsys.net Received: from b9k4u9 (unverified [204.49.76.192]) by access.aic-fl.com (Rockliffe SMTPRA 4.5.6) with SMTP id for ; Mon, 6 Feb 2006 21:58:35 -0600 Message-ID: <003001c62bac$af382760$c04c31cc@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 22:06:44 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002B_01C62B69.9DDA2EC0" 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_002B_01C62B69.9DDA2EC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message ----- Original Message -----=20 From: george lendich=20 To: Rotary motors in aircraft=20 Sent: Monday, February 06, 2006 7:06 PM 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 Richard,=20 Do you have a photo of that donut type damper - is it similar to = the BMW type?=20 Have a look on the internet for Lord Dynaflex Couplings, that's = what Don Dunbar is using and sounds like it is ideal for the single = rotor, I prefer Tracy's set-up for the 2 rotor. George ( down under) George, yes, it is the same in principle as on a BMW. In Europe it is a = GIUBO from Italy. Richard Sohn N-2071U ------=_NextPart_000_002B_01C62B69.9DDA2EC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
----- Original Message -----
From:=20 george=20 lendich
Sent: Monday, February 06, 2006 = 7:06=20 PM
Subject: [FlyRotary] Re: Single = rotor=20 smooth as silk now

 

Would a single with no dampers put the = resonance
beyond=20 the 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=20 it was probably not going to be much of a test.  =
 
How much gear lash is = there on a=20 typical Hirth, or Rotax gear box? 
 
Cheers,
Rusty
 
 

There are two issues to cope with, one is = resonances=20 and the other is transferring the torque pulses. The torque pulses = are=20 transferred completely in a indefinitly stiff system. We do not = want that,=20 because of the internal forces involved. That leaves the = resonances=20 created by coupling and element flexing properties. I believe the = only way=20 to stay out of the resonances is to keep them low. This is what = ROTAX is=20 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=20 observed any rattle on my C-Box with the SOOB.

My ROTAX C box has about 1/8" gear = lash at the=20 tip of th 72" prop. I have seen the same on others, seems to be=20 normal.
 
Richard = Sohn
N-2071U
 
Richard,
Do you have a photo of that donut = type damper=20 - is it similar to the BMW type? 
Have a look on the internet for = Lord Dynaflex=20 Couplings, that's what Don Dunbar is using and sounds like it is = ideal for=20 the single rotor, I prefer Tracy's set-up for the 2 = rotor.
George ( down under)
 
George,
 yes, it is the same = in principle=20 as on a BMW. In Europe it is a GIUBO from = Italy.
 
Richard=20 Sohn
N-2071U
 
 
=


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