X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 06 Jun 2007 09:34:11 -0400 Message-ID: X-Original-Return-Path: Received: from [69.146.254.20] (HELO arilabs.net) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2086558 for lml@lancaironline.net; Wed, 06 Jun 2007 00:28:07 -0400 Received-SPF: none receiver=logan.com; client-ip=69.146.254.20; envelope-from=Kevin@arilabs.net Subject: RE: [LML] Re: IV-P Rudder Trim MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C7A7F2.FD861B64" X-Original-Date: Tue, 5 Jun 2007 22:27:19 -0600 Content-class: urn:content-classes:message X-MimeOLE: Produced By Microsoft Exchange V6.5 X-Original-Message-ID: <7141427652BB3049A7DBF1084B67805B0F8032@penumbra.arilabs.net> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Re: IV-P Rudder Trim Thread-Index: Acen7iTpJo0ofaxWQ+GzwN9Ehp2ZXQAA8SVA From: "Kevin Stallard" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C7A7F2.FD861B64 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I'm not anywhere near an expert on flutter, but isn't flutter destructive? I mean if an airframe experiences flutter, it doesn't just wear out hinges, my understanding is the airframe ceases to be an airframe at that point. I don't recall having ever read about any mid-flight break up of a Lancair except those that happen to wander into a thunderstorm here and there. =20 Vibration is completely different and there could be other reasons at "play" regarding the premature wearing of these hinges. Chris Zavatson has some interesting things on hinges and vibration, give it a read... =20 http://www.n91cz.com/HingePlay/hinges.htm =20 Bottom line, I don't think flutter in a Lancair is worth worrying about... =20 Kevin =20 =20 Scott, I'm new to the LML site but I have built several aircraft over the years. One thing that scares me on the Lancair is flutter. I recently found a IV elevator trim that could easily be moved up and down as much as 1" at the trailing edge. It turned out to the hinge that the tab was attached to was bending. The owner had not had a problem with flutter but the hinge was completely worn out due to vibration in only a couple hundred hours. Lowering the attach point on the horn reduces the leverage and increases the movement of the tab. This will make it too sensitive and lessen the arm needed to prevent flutter. I don't recommend it. Lanny=20 =20 ------_=_NextPart_001_01C7A7F2.FD861B64 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I’m not anywhere near an = expert on flutter, but isn’t flutter destructive?  I mean if an = airframe experiences flutter, it doesn’t just wear out hinges, my = understanding is the airframe ceases to be an airframe at that point.  I don’t = recall having ever read about any mid-flight break up of a Lancair except those = that happen to wander into a thunderstorm here and = there.

 

Vibration is completely different = and there could be other reasons at “play” regarding the = premature wearing of these hinges.  Chris Zavatson has some interesting = things on hinges and vibration, give it a read…

 

http://www.n91cz.com/H= ingePlay/hinges.htm

 

Bottom line, I don’t think = flutter in a Lancair is worth worrying about…

 

Kevin

 

 

Scott,

I’m new to the LML site but I = have built several aircraft over the years.  One thing that scares me on = the Lancair is flutter.  I recently found a IV elevator trim that could easily = be moved up and down as much as 1” at the trailing edge.  It turned out = to the hinge that the tab was attached to was bending.  The owner had not had a = problem with flutter but the hinge was completely worn out due to vibration in only a = couple hundred hours.  Lowering the attach point on the horn reduces the = leverage and increases the movement of the tab.  This will make it too sensitive = and lessen the arm needed to prevent flutter.  I don’t recommend = it.

Lanny

 

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