X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Mon, 07 Dec 2009 11:51:38 -0500 Message-ID: X-Original-Return-Path: Received: from vms173007pub.verizon.net ([206.46.173.7] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 4006038 for lml@lancaironline.net; Mon, 07 Dec 2009 11:09:18 -0500 Received-SPF: pass receiver=logan.com; client-ip=206.46.173.7; envelope-from=skipslater@verizon.net Received: from SkipPC ([173.58.203.163]) by vms173007.mailsrvcs.net (Sun Java(tm) System Messaging Server 6.3-7.04 (built Sep 26 2008; 32bit)) with ESMTPA id <0KUA00C77I64UO5C@vms173007.mailsrvcs.net> for lml@lancaironline.net; Mon, 07 Dec 2009 10:08:29 -0600 (CST) X-Original-Message-id: <3BEA2F315CAF451CA44C65EA9128F082@SkipPC> From: "Skip Slater" X-Original-To: "Lancair Mailing List" References: In-reply-to: Subject: Re: [LML] Re: Flutter and nose wheel shimmy X-Original-Date: Mon, 07 Dec 2009 08:08:09 -0800 MIME-version: 1.0 Content-type: multipart/alternative; boundary="----=_NextPart_000_0026_01CA7714.6A038FB0" X-Priority: 3 X-MSMail-priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8089.726 X-MIMEOLE: Produced By Microsoft MimeOLE V14.0.8089.726 This is a multi-part message in MIME format. ------=_NextPart_000_0026_01CA7714.6A038FB0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Gary, I had really bad shimmy when braking during my initial taxi tests = back in 2002. We assumed it was the nose shimmying - it sure felt that = way. It was so bad I removed the strut and sent it back to Lancair to = have it checked out. They pulled it apart, found nothing wrong, = serviced it and sent it back. Next taxi test has the same results. So = I did a medium speed taxi past my builder guru and hit the brakes. He = said it was not the nose, but my right main mount that was shaking like = a leaf. Grove Aircraft is on the same field where I built the plane and = Robbie Grove offered to check my brake rotors. He found an extremely = small warp in the right one. He turned that rotor for me, I put it back = on and the problem disappeared completely. I have since periodically had the common shimmy many builders have = when braking through about 30 knots. When it's gotten bad enough, I've = put a new rotor on and the problem goes away. I know my shimmy is not = from the nose - it's from one or both of my mains oscillating like a = pitch fork when I brake if my rotors have even the slightest bit of warp = in them. A momentary release and reapplication of the brakes is all it = takes to stop it. Selective releasing of one brake at a time is how I = determine which one is causing the problem. If you want a new rotor, you can order one from Lancair. I now have = two replacement rotors on my plane and plan to take the originals to an = auto shop to see if they can turn them so I'll have replacements ready = to install when I need them in the future. Skip ------=_NextPart_000_0026_01CA7714.6A038FB0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Gary,
   I had really bad shimmy = when braking=20 during my initial taxi tests back in 2002.  We assumed it was the = nose=20 shimmying - it sure felt that way.  It was so bad I removed = the strut=20 and sent it back to Lancair to have it checked out.  They pulled it = apart,=20 found nothing wrong, serviced it and sent it back.  Next taxi = test has=20 the same results.  So I did a medium speed taxi past my builder = guru and=20 hit the brakes.  He said it was not the nose, but my right main = mount that=20 was shaking like a leaf.
   Grove Aircraft is on the = same field=20 where I built the plane and Robbie Grove offered to check my brake=20 rotors.  He found an extremely small warp in the right one.  = He turned=20 that rotor for me, I put it back on and the problem disappeared=20 completely.
   I have since periodically = had the=20 common shimmy many builders have when braking through about 30 = knots.  When=20 it's gotten bad enough, I've put a new rotor on and the problem goes = away. =20 I know my shimmy is not from the nose - it's from one or both of my = mains=20 oscillating like a pitch fork when I brake if my rotors have even the = slightest=20 bit of warp in them.  A momentary release and reapplication of = the=20 brakes is all it takes to stop it.  Selective releasing of one brake at a time is how I = determine which=20 one is causing the problem.
   If you want a new rotor, = you can order=20 one from Lancair.  I now have two replacement rotors on my plane = and plan=20 to take the originals to an auto shop to see if they can turn them so = I'll have=20 replacements ready to install when I need them in the = future.
   = Skip
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