X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 26 Aug 2007 18:00:10 -0400 Message-ID: X-Original-Return-Path: Received: from bay0-omc2-s24.bay0.hotmail.com ([65.54.246.160] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2286112 for lml@lancaironline.net; Sun, 26 Aug 2007 17:56:38 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.54.246.160; envelope-from=joscales98@hotmail.com Received: from hotmail.com ([65.55.135.26]) by bay0-omc2-s24.bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.2668); Sun, 26 Aug 2007 14:56:00 -0700 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sun, 26 Aug 2007 14:56:00 -0700 X-Original-Message-ID: Received: from 75.81.226.134 by BAY130-DAV16.phx.gbl with DAV; Sun, 26 Aug 2007 21:55:59 +0000 X-Originating-IP: [75.81.226.134] X-Originating-Email: [joscales98@hotmail.com] X-Sender: joscales98@hotmail.com From: "Jim Scales" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: ES Strut issues X-Original-Date: Sun, 26 Aug 2007 16:56:05 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0AA0_01C7E801.FE1C0910" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MIMEOLE: Produced By MSN MimeOLE V9.50.0039.1900 Seal-Send-Time: Sun, 26 Aug 2007 16:56:05 -0500 X-OriginalArrivalTime: 26 Aug 2007 21:56:00.0612 (UTC) FILETIME=[E3C7FA40:01C7E82B] X-Original-Return-Path: joscales98@hotmail.com This is a multi-part message in MIME format. ------=_NextPart_000_0AA0_01C7E801.FE1C0910 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable How does the stick behave when the shake occurs? Jim ----- Original Message -----=20 From: Skip Slater=20 To: lml@lancaironline.net=20 Sent: Sunday, August 26, 2007 1:03 PM Subject: [LML] Re: ES Strut issues Jim, My shimmy symptoms sound identical to yours - same onset speed, = same results from releasing and smoothly re-applying brakes. To me, my = butt says the shaking is coming from the nose, but I know from my first = experience when I had a witness that the origin may be from one or both = of the mains, which seems to translate forward. =20 Like Mike Easley, I'll hold aft stick as I roll out to keep as much = weight as possible off the mains during rollout. I also retract the = flaps as soon as I'm on the ground to put more weight on the mains. I = think that also takes a bit of weight off the nose. I haven't really = taken notice of the effect of a more aft CG on the shaking, but I'll pay = more attention to that in the future. If I have a short runway (like the 2000' one we use for our Young = Eagles events), I land on-speed and do heavier braking as soon as I'm on = the ground, which gives me a lot of deceleration before the shimmy = onset. That results in a much shorter landing rollout. I don't have a taxi speed that I avoid, though I can get a shaking = if I try to brake lightly at low taxi speeds. I don't get any shimmy at = all when taxiing with the brakes off.=20 The surprising thing to me is what a well known issue this is and = the lack of a solution for it. You'd think that between some of the = engineering types who are flying ES's and the factory guys, someone = would have put their finger on exactly what causes this and come up with = a fix. I think Lancair has chosen to bury their heads in the sand on = this other than to equip the new kits with a beefier nose strut. But = there are a lot of old struts flying out there and at least three of = them that I know of have had catastrophic failure, two resulting in = collapsed nose gears, broken mounts and $50K+ in damage. In the other = case, it was a miracle that the strut didn't fold, as the post flight = tear down of the strut revealed a total failure of one of the damping O = rings. Maybe your video tests will point us in the right direction. I = sure hope so! Skip ------=_NextPart_000_0AA0_01C7E801.FE1C0910 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
How does the stick behave when the shake occurs?
 
Jim
----- Original Message -----
From: Skip=20 Slater
Sent: Sunday, August 26, 2007 = 1:03=20 PM
Subject: [LML] Re: ES Strut = issues

Jim,
   My shimmy symptoms sound = identical=20 to yours - same onset speed, same results from releasing and smoothly=20 re-applying brakes.  To me, my butt says the shaking is coming = from the=20 nose, but I know from my first experience when I had a witness that = the origin=20 may be from one or both of the mains, which seems to translate = forward. =20
   Like Mike Easley, = I'll hold aft=20 stick as I roll out to keep as much weight as possible off the mains = during=20 rollout.  I also retract the flaps as soon as I'm on the ground = to put=20 more weight on the mains.  I think that also takes a bit of = weight off=20 the nose. I haven't really taken notice of the effect of a more = aft CG on=20 the shaking, but I'll pay more attention to that in the = future.
   If I have a short runway = (like the=20 2000' one we use for our Young Eagles events), I land on-speed and do = heavier=20 braking as soon as I'm on the ground, which gives me a lot of = deceleration=20 before the shimmy onset.  That results in a much shorter landing=20 rollout.
   I don't have a taxi = speed that I=20 avoid, though I can get a shaking if I try to brake lightly at low = taxi=20 speeds.  I don't get any shimmy at all when taxiing with the = brakes=20 off. 
   The surprising thing to = me is what a=20 well known issue this is and the lack of a solution for it.  = You'd think=20 that between some of the engineering types who are flying ES's and the = factory=20 guys, someone would have put their finger on exactly what causes = this and=20 come up with a fix.  I think Lancair has chosen to bury their = heads in=20 the sand on this other than to equip the new kits with a beefier nose=20 strut.  But there are a lot of old struts flying out there and at = least=20 three of them that I know of have had catastrophic failure, two = resulting=20 in collapsed nose gears, broken mounts and $50K+ in damage.  In = the other=20 case, it was a miracle that the strut didn't fold, as the post flight = tear=20 down of the strut revealed a total failure of one of the damping = O=20 rings.
   Maybe your video tests = will point us=20 in the right direction.  I sure hope so!
  =20 Skip 
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