X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mx2.netapp.com ([216.240.18.37] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTPS id 5051603 for flyrotary@lancaironline.net; Thu, 14 Jul 2011 10:04:33 -0400 Received-SPF: none receiver=logan.com; client-ip=216.240.18.37; envelope-from=echristley@att.net X-IronPort-AV: E=Sophos;i="4.65,529,1304319600"; d="scan'208";a="562736335" Received: from smtp1.corp.netapp.com ([10.57.156.124]) by mx2-out.netapp.com with ESMTP; 14 Jul 2011 07:03:32 -0700 Received: from [10.62.16.167] (ernestc-laptop.hq.netapp.com [10.62.16.167]) by smtp1.corp.netapp.com (8.13.1/8.13.1/NTAP-1.6) with ESMTP id p6EE3VQC016671 for ; Thu, 14 Jul 2011 07:03:31 -0700 (PDT) Message-ID: <4E1EF72C.1000106@att.net> Date: Thu, 14 Jul 2011 10:03:24 -0400 From: Ernest Christley Reply-To: echristley@att.net User-Agent: Thunderbird 2.0.0.24 (X11/20100623) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Flywheel sizes References: In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable Andrew Martin wrote: > Whats the real reason why a flex plate would crack instead of flex?=20 > I=92d find it hard to believe its from gearbox misalignment, Tracy=92s = > tolerances and fit seem pretty tight to me,=20 > Is it possible the culprit is the starter motor? >=20 Theory 1) There was an indication that some parts had started to get loos= e. Tolerances, alignments, and fit all go out=20 the window once things get loose and start moving around. Theory 2) Tracy used a rubber isolator between the adapter plate and the = flexplate. Under high load, there would be a=20 bending force on the connecting bolt that would try to twist the flex pla= te at the bolt holes. Looking at the way the flexplate was split between all the bolt holes, it= seems feasible to me (from my position far,=20 far away) that the first could have led to the second.