X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 26 Aug 2007 14:03:39 -0400 Message-ID: X-Original-Return-Path: Received: from sccrmhc14.comcast.net ([204.127.200.84] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2285676 for lml@lancaironline.net; Sun, 26 Aug 2007 11:41:42 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.200.84; envelope-from=nrgarvin@comcast.net Received: from gateway508ge (c-71-234-125-121.hsd1.ct.comcast.net[71.234.125.121]) by comcast.net (sccrmhc14) with SMTP id <200708261540550140008jrse>; Sun, 26 Aug 2007 15:41:05 +0000 From: "Neal Garvin" X-Original-To: "'Lancair Mailing List'" References: Subject: RE: [LML] ES engine mount cracks and breaks X-Original-Date: Sun, 26 Aug 2007 11:41:02 -0400 X-Original-Message-ID: <005301c7e7f7$898917f0$6501a8c0@gateway508ge> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0054_01C7E7D6.027777F0" X-Mailer: Microsoft Office Outlook 11 Thread-Index: AcfnX+aYE31PExzQTveSZsn37uftWwAlPKgA X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0054_01C7E7D6.027777F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable It looks to me like this engine mount was not stress-relieved after = welding. Any 4130 weld should be stress relieved to eliminate the = =93brittleness=94 and high stresses at the weld due to the rapid cooling and localized = hardening at the weld area. Engine mounts and landing gear would be critical items typically made from 4130 tubing weldaments requiring stress relieving. Stress relieving requires 4130 requires 1100 degF and slow cooling.=20 =20 To determine if the mount was stress relieved, take some hardness = strikes (readings) at the weld area and then several more =BD=94 apart for = several inches from the weld. The hardness profile would show higher readings = right near the weld.=20 =20 -Neal Garvin Glasair SIIS-RG =20 _____ =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Jim Nordin Sent: Saturday, August 25, 2007 5:36 PM To: lml@lancaironline.net Subject: [LML] ES engine mount cracks and breaks =20 Here=92s a note from Lon Kelley regarding his ES motor mount issues. I = hope these pictures will encourage you all to examine closely =85 very = closely =85 your motor mount. Personally I don=92t see how there wasn=92t a very = serious accident because of this problem =85 Lon and Pam were just plain lucky. Jim Nordin =20 _____ =20 From: PKkelle@aol.com [mailto:PKkelle@aol.com]=20 Sent: Saturday, August 25, 2007 3:40 PM To: panelmaker@earthlink.net Subject: ES engine mount =20 Jim, here is some information on the recently discovered engine mount problems in my ES. The pictures are attached and show some major breaks = and widespread cracking in the welds. It is my opinion that these cracks indicate improper welding procedures in my mount, and there may also be = a problem in other early ES mounts. I have not got any professional = opinion on the welds, and really don't intend to, but the cracks all appear to be = in the heat-affected zone adjacent to the weld, and this is the area of = concern in most high carbon material where embrittlement might occur.=20 =20 I believe these cracks have been there for a long time, and we missed = them during inspections. My only excuse for this is that they wouldn't be = visible under the paint. What led to my finding them was some very rough taxiing = at Sun N Fun, Oshkosh and a rough grass strip this summer. At the last oil change I specifically wanted to look at the nose-gear mount, and feel = very lucky that we took the bottom cowling off, and I stuck my nose down = there and chipped some paint back. Of course the two broken members were = pretty obvious if you were looking. My plane has 1225 hours and this mount was = made in 1994.=20 =20 Incidentally, we sent our strut back to Lancair in about 1999, and Vern rebuilt it. We have not experienced serious shimmy with it, and I = don=92t believe the weld cracks are associated with shimmy. Lon Kelley =20 No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.12.6/971 - Release Date: = 8/24/2007 2:59 PM ------=_NextPart_000_0054_01C7E7D6.027777F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

It looks to me like this engine = mount was not stress-relieved after welding. Any 4130 weld should be stress = relieved to eliminate the “brittleness” and high stresses at the weld = due to the rapid cooling and localized hardening at the weld area. Engine = mounts and landing gear would be critical items typically made from 4130 tubing = weldaments requiring stress relieving. Stress relieving requires 4130 requires 1100 = degF and slow cooling.

 

To determine if the mount was = stress relieved, take some hardness strikes (readings) at the weld area and = then several more =BD” apart for several inches from the weld. The = hardness profile would show higher readings right near the weld. =

 

-Neal = Garvin

Glasair = SIIS-RG

 

From: = Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Jim Nordin
Sent: Saturday, August = 25, 2007 5:36 PM
To: = lml@lancaironline.net
Subject: [LML] ES engine = mount cracks and breaks

 

Here’s a note from Lon Kelley regarding his ES motor mount issues. I hope these pictures will = encourage you all to examine closely … very closely … your motor mount. Personally I don’t see how there wasn’t a very serious = accident because of this problem … Lon and Pam were just plain = lucky.

Jim = Nordin

 

From: = PKkelle@aol.com [mailto:PKkelle@aol.com]
Sent: Saturday, August = 25, 2007 3:40 PM
To: = panelmaker@earthlink.net
Subject: ES engine = mount

 

Jim, here is some information on the recently discovered engine = mount problems in my ES. The pictures are attached and show some major breaks = and widespread cracking in the welds. It is my opinion that these cracks = indicate improper welding procedures in my mount, and there may also be a problem = in other early ES mounts. I have not got any professional opinion on the = welds, and really don't intend to, but the cracks all appear to be in the heat-affected zone adjacent to the weld, and this is the area of concern = in most high carbon material where embrittlement  might occur. =

 

I believe these cracks have been there for a long time, and we = missed them during inspections. My only excuse for this is that they wouldn't = be visible under the paint. What led to my finding them was some very rough taxiing at Sun N Fun, Oshkosh and a rough grass strip this summer. At the last oil change I = specifically wanted to look at the nose-gear mount, and feel very lucky that we took = the bottom cowling off, and I stuck my nose down there and chipped some = paint back. Of course the two broken members were pretty obvious if you were = looking. My plane has 1225 hours and this mount was made in 1994. =

 

Incidentally, we sent our strut back to Lancair in about 1999, = and Vern rebuilt it. We have not experienced serious shimmy with it, and I = don’t believe the weld cracks are associated with shimmy.  Lon = Kelley

 


No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.484 / Virus Database: 269.12.6/971 - Release Date: = 8/24/2007 2:59 PM

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