X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4178938 for flyrotary@lancaironline.net; Thu, 25 Mar 2010 17:46:42 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id 9F404173570 for ; Fri, 26 Mar 2010 05:46:07 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id BD442BEC009 for ; Fri, 26 Mar 2010 05:46:06 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Adaptor plate rivets Date: Fri, 26 Mar 2010 07:30:33 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0049_01CACCB6.3867EE90" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100325-1, 03/25/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0049_01CACCB6.3867EE90 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable No one has mentioned it yet but I'm wondering if heat could be a = factor, one of them anyway. George( down under) BTW, did you have visible smoke trails? I don't. I wonder if there = was some sort of change in the way the riveting was done. =20 Dave; There were maybe a couple very slight trails on the flange side = (toward the re-drive). On the other side (I guess the head side of the = rivets) where I could only see about 4-5 of them through the holes in = the flywheel (ring gear); all had distinct dark trails. It's possible that power is the main issue (average torque), but it = seems to me that peak torque and torque variation amplitude are what are = going to matter most. You and Mark are going to have lower peak torque = than those of us with turbo engines, and with 20B's you are are going to = have lower torque amplitude than even those with n.a. 13B's. =20 One would think that is true; but you can't be sure. It is possible = the 20B may have some harmonics (resonance vibration) somewhere in the = range of operation that the 13B doesn't have. Seems unlikely with the = snubbers and the 'play' in the system, but . . . We need more feedback = from all the users with more than 150 hours, or so, to see what the = pattern is. I'm not aware of rivet changes - Tracy? Mark and I both have constant speed props and I think Al does also. = Don't see how it could make any difference but worth considering in the = investigation. Bobby I have a fixed pitch Catto. The mass of the prop would likely be a = factor - if there is some torsional vibration involved. My Catto only = weighs about 16 lbs; plus 3-4 for the extension and spinner. I have 180 = hours and barely detectable rivet wear; Mark apparently has more wear at = about 150. Al ------=_NextPart_000_0049_01CACCB6.3867EE90 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 No one has mentioned it yet but = I'm wondering=20 if heat could be a factor, one of them anyway.
George( down under)

BTW, did you have visible = smoke=20 trails?  I don't.  I wonder if there was some sort of change = in the=20 way the riveting was done. 

Dave;

 

There = were maybe a=20 couple very slight trails on the flange side (toward the re-drive). =  On=20 the other side (I guess the head side of the rivets) where I could = only see=20 about 4-5 of them through the holes in the flywheel (ring gear); all = had=20 distinct dark trails.

 

It's = possible that=20 power is the main issue (average torque), but it seems to me that peak = torque=20 and torque variation amplitude are what are going to = matter=20 most.  You and Mark are going to have lower peak torque than = those of us=20 with turbo engines, and with 20B's you are are going to have lower = torque=20 amplitude than even those with n.a. 13B's. 

One=20 would think that is true; but you can=92t be sure.  It is = possible the 20B=20 may have some harmonics (resonance vibration) somewhere in the range = of=20 operation that the 13B doesn=92t have. Seems unlikely with the = snubbers and the=20 =91play=92 in the system, but . . .  We need more feedback from = all the users=20 with more than 150 hours, or so, to see what the pattern is. =  I=92m not=20 aware of rivet changes =96 Tracy?

Mark and=20 I both have constant speed props and I think Al does also. Don't see = how it=20 could make any difference but worth considering in the = investigation. =20 Bobby

I have=20 a fixed pitch Catto.  The mass of the prop would likely be a = factor =96=20 if there is some = torsional=20 vibration involved.  My Catto only weighs about 16 lbs; plus 3-4 = for the=20 extension and spinner. I have 180 hours and barely detectable rivet = wear; Mark=20 apparently has more wear at about 150.

Al

 

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