X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 10 Apr 2009 20:21:55 -0400 Message-ID: X-Original-Return-Path: Received: from imr-d01.mx.aol.com ([205.188.157.39] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3576273 for lml@lancaironline.net; Fri, 10 Apr 2009 07:20:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.39; envelope-from=MikeEasley@aol.com Received: from imo-ma02.mx.aol.com (imo-ma02.mx.aol.com [64.12.78.137]) by imr-d01.mx.aol.com (v107.10) with ESMTP id RELAYIN10-b49df2b602b; Fri, 10 Apr 2009 07:20:00 -0400 Received: from MikeEasley@aol.com by imo-ma02.mx.aol.com (mail_out_v40_r1.5.) id q.d41.3b792ef8 (37659) for ; Fri, 10 Apr 2009 07:19:57 -0400 (EDT) Received: from MikeNotebook (ac839d54.ipt.aol.com [172.131.157.84]) by cia-mb07.mx.aol.com (v123.3) with ESMTP id MAILCIAMB071-931b49df2b5a21; Fri, 10 Apr 2009 07:19:56 -0400 X-Original-Date: Fri, 10 Apr 2009 05:18:52 -0600 From: mikeeasley Subject: Re: [LML] Re: LNC2 Aileron bellcrank bearing failure X-Original-To: "Lancair Mailing List" In-Reply-To: X-Original-Message-ID: <3394a0d1.12e5.4428.bfd8.99cce5282d38@aol.com> References: X-Mailer: Nexus Desktop Client 3.1.20.1 MIME-Version: 1.0 Content-Type: MULTIPART/alternative; BOUNDARY=2082937b-fbae-47af-ae8c-f100d5cb3afa Content-Transfer-Encoding: 8bit X-AOL-IP: 64.12.78.137 X-Spam-Flag:NO --2082937b-fbae-47af-ae8c-f100d5cb3afa Content-Type: TEXT/plain; charset=us-ascii I replaced the left side aileron 90 degree bellcrank in my ES at 150 hours. It had significantly more play than the right side. The actual bearing had developed play, not the mounting of the bearing in the aluminum plates. I'm not sure if I didn't notice it a year earlier or whether it developed that much play in a year. I now thoroughly check for side play in all the bellcranks annually. Another ES had an aileron bellcrank bearing replaced due to excessive play at a couple hundred hours. One factor is all the fiberglass dust that flies around during construction gets into the pre-lubricated bearings and causes wear. The bearings used in the bellcranks are not designed to handle significant side loads. Since the aileron bellcranks support the weight of the pushrods, that likely contributes to them wearing out more quickly. Another builder has investigated the possibility of the resonant frequency of the pushrod causing some vibration that would accelerate bearing wear, but no conclusive results. Mike Easley Colorado Springs ES --2082937b-fbae-47af-ae8c-f100d5cb3afa Content-Type: TEXT/html; charset=utf-8 Content-Transfer-Encoding: 8BIT
I replaced the left side aileron 90 degree bellcrank in my ES at 150 hours.  It had significantly more play than the right side.  The actual bearing had developed play, not the mounting of the bearing in the aluminum plates.  I'm not sure if I didn't notice it a year earlier or whether it developed that much play in a year.  I now thoroughly check for side play in all the bellcranks annually.  Another ES had an aileron bellcrank bearing replaced due to excessive play at a couple hundred hours.
 
One factor is all the fiberglass dust that flies around during construction gets into the pre-lubricated bearings and causes wear.  The bearings used in the bellcranks are not designed to handle significant side loads.  Since the aileron bellcranks support the weight of the pushrods, that likely contributes to them wearing out more quickly.  Another builder has investigated the possibility of the resonant frequency of the pushrod causing some vibration that would accelerate bearing wear, but no conclusive results.
 
Mike Easley
Colorado Springs
ES
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