X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 26 Jun 2008 21:50:45 -0400 Message-ID: X-Original-Return-Path: Received: from smtp1.av-mx.com ([137.118.16.57] verified) by logan.com (CommuniGate Pro SMTP 5.2.4) with ESMTP id 2990799 for lml@lancaironline.net; Wed, 25 Jun 2008 10:39:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.57; envelope-from=pinetownd@volcano.net Received: from DennisDell (65-166-101-93.dsl.volcano.net [65.166.101.93]) (Authenticated sender: pinetownd@volcano.net) by smtp1.av-mx.com (Postfix) with ESMTP id 1DA64290415 for ; Wed, 25 Jun 2008 10:38:45 -0400 (EDT) X-Original-Message-ID: <513DEE75069040249532266A13A427AD@DennisDell> From: "Dennis Johnson" X-Original-To: "Lancair Mailing List" Subject: Runaway Trim X-Original-Date: Wed, 25 Jun 2008 07:38:38 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0054_01C8D696.7BB8DB90" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512 This is a multi-part message in MIME format. ------=_NextPart_000_0054_01C8D696.7BB8DB90 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Hi Robert, My understanding from talking with the RAC guys, who make the trim = components I installed in my Legacy, is that stuck (runaway) trim is = unlikely. (Actually, they said it was impossible, but I find it hard to = use that word.) The trim servo must receive power to operate. A runaway can only occur = if either the trim switch or the trim relay is stuck in the "on" = position. If that happens, moving the trim switch to the opposite = position should almost certainly cause the switch or relay to open, = clearing the problem. (Wiring faults could also cause runaway trim, but = I was careful to protect the wiring when I installed it and therefore do = not consider this cause to be a realistic possibility during the time I = own my Legacy.)=20 I've given this some thought and have decided that runaway trim is = possible, but unlikely. I've decided that the additional parts count = and complexity to reduce the chance of an already unlikely runaway trim = isn't justified. I've practiced this and believe I can control the = airplane with full trim if I slow it down, although my arm would get = tired after a while. Best, Dennis Johnson Legacy, 140 hours ------=_NextPart_000_0054_01C8D696.7BB8DB90 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

Hi Robert,

My understanding from talking with the RAC guys, who make the trim=20 components I installed in my Legacy, is that stuck (runaway) trim is=20 unlikely. (Actually, they said it was impossible, but I find it = hard to=20 use that word.)

The trim servo must receive power to operate. A runaway = can only=20 occur if either the trim switch or the trim relay is stuck in the "on"=20 position. If that happens, moving the trim switch to the opposite = position=20 should almost certainly cause the switch or relay to open, clearing the=20 problem. (Wiring faults could also cause runaway trim, but I was = careful=20 to protect the wiring when I installed it and therefore do not = consider=20 this cause to be a realistic possibility during the time I own my=20 Legacy.)

I've given this some thought and have decided that runaway trim is=20 possible, but unlikely. I've decided that the additional parts = count and=20 complexity to reduce the chance of an already unlikely runaway=20 trim isn't justified. I've practiced this and believe I can = control=20 the airplane with full trim if I slow it down, although my arm = would get=20 tired after a while.

Best,

Dennis Johnson

Legacy, 140 hours

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