X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 06 Jun 2007 16:45:14 -0400 Message-ID: X-Original-Return-Path: Received: from pop-sarus.atl.sa.earthlink.net ([207.69.195.72] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2087858 for lml@lancaironline.net; Wed, 06 Jun 2007 14:57:08 -0400 Received-SPF: none receiver=logan.com; client-ip=207.69.195.72; envelope-from=pbricker@earthlink.net Received: from user-vcaukdq.dsl.mindspring.com ([216.175.81.186] helo=paulrzm5oth3zt) by pop-sarus.atl.sa.earthlink.net with esmtp (Exim 3.36 #1) id 1Hw0gJ-00078N-00 for lml@lancaironline.net; Wed, 06 Jun 2007 14:56:31 -0400 From: "Paul Bricker" X-Original-To: "'Lancair Mailing List'" References: Subject: RE: [LML] Re: IV-P Rudder Trim X-Original-Date: Wed, 6 Jun 2007 11:56:24 -0700 X-Original-Message-ID: <006701c7a86c$61d100d0$6501a8c0@paulrzm5oth3zt> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0068_01C7A831.B57228D0" X-Mailer: Microsoft Office Outlook 11 thread-index: AceoXhoArNlTiwa+T1KlYfoHLjChhQADbMCA X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0068_01C7A831.B57228D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I=92ll measure mine this afternoon, but my memory is the trailing edge = of the tab moves about 2 inches. If you think about the geometry, the servo has = 0.7 travel to an arm that is about 1 =BC inches long. The tab is about 4 = inches at the widest point. This would give 0.7*(4/1.25) =3D 2.24 inch peak-peak deflection. Like I said, I=92m measure it and report. =20 Paul Bricker N63PB =20 _____ =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of vtailjeff@aol.com Sent: Wednesday, June 06, 2007 10:14 AM To: lml@lancaironline.net Subject: [LML] Re: IV-P Rudder Trim =20 Lanny, =20 Who's airplane was this. 1" sounds like a lot of movement on an elevator trim tab. I don't even think they travel 1" stop to stop, so how could = this be? =20 Jeff I=92m 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=94 at = the trailing edge. It turned out to the hinge that the tab was attached to = was bending.=20 -----Original Message----- From: Kevin Stallard=20 To: lml@lancaironline.net Sent: Wed, 6 Jun 2007 8:34 am Subject: [LML] Re: IV-P Rudder Trim I=92m not anywhere near an expert on flutter, but isn=92t flutter = destructive? I mean if an airframe experiences flutter, it doesn=92t just wear out = hinges, my understanding is the airframe ceases to be an airframe at that point. = I don=92t 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 = =93play=94 regarding the premature wearing of these hinges. Chris Zavatson has = some interesting things on hinges and vibration, give it a read=85 =20 http://www.n91cz.com/HingePlay/hinges.htm =20 Bottom line, I don=92t think flutter in a Lancair is worth worrying = about=85 =20 Kevin =20 =20 Scott, I=92m 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=94 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=92t recommend it. Lanny=20 =20 _____ =20 size=3D2 width=3D"100%" align=3Dcenter>=20 AOL now offers free email to everyone. Find out more about what's free = from AOL at AOL.com. ------=_NextPart_000_0068_01C7A831.B57228D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

I’ll measure mine this = afternoon, but my memory is the trailing edge of the tab moves about 2 inches. If you = think about the geometry, the servo has 0.7 travel to an arm that is about 1 =BC = inches long. The tab is about 4 inches at the widest point. This would give = 0.7*(4/1.25) =3D 2.24 inch peak-peak deflection. Like I said, I’m measure it and = report.

 

Paul = Bricker

N63PB

 

From: = Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of vtailjeff@aol.com
Sent: Wednesday, June 06, = 2007 10:14 AM
To: = lml@lancaironline.net
Subject: [LML] Re: IV-P = Rudder Trim

 

Lanny,

 

Who's airplane was this. 1" sounds like a lot of movement = on an elevator trim tab. I don't even think they travel 1" stop to stop, = so how could this be?

 

Jeff

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. 




-----Original Message-----
From: Kevin Stallard
To: lml@lancaironline.net
Sent: Wed, 6 Jun 2007 8:34 am
Subject: [LML] Re: IV-P Rudder Trim

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…

 

 

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

 

= size=3D2 width=3D"100%" align=3Dcenter>

AOL now offers free email to everyone. Find = out more about what's free from AOL at AOL.com.

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