X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from imo-m24.mx.aol.com ([64.12.137.5] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1874141 for flyrotary@lancaironline.net; Wed, 28 Feb 2007 12:00:44 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.5; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m24.mx.aol.com (mail_out_v38_r7.6.) id q.bed.a3748d8 (45776) for ; Wed, 28 Feb 2007 11:59:41 -0500 (EST) Received: from FWM-M14 (fwm-m14.webmail.aol.com [64.12.168.78]) by ciaaol-r01.mx.aol.com (v114_r3.2) with ESMTP id MAILCIAAOLR015-b2d045e5b4fc3d8; Wed, 28 Feb 2007 11:59:40 -0500 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: engine mount 4130 vs 304 SS Date: Wed, 28 Feb 2007 11:59:40 -0500 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: wrjjrs@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8C92970F89AC702_1F74_1C35_FWM-M14.sysops.aol.com" X-Mailer: AOL WebMail 24019 Received: from 65.161.241.3 by FWM-M14.sysops.aol.com (64.12.168.78) with HTTP (WebMailUI); Wed, 28 Feb 2007 11:59:40 -0500 Message-Id: <8C92970F89F8BB2-1F74-E5B@FWM-M14.sysops.aol.com> X-AOL-IP: 64.12.168.78 X-Spam-Flag: NO ----------MB_8C92970F89AC702_1F74_1C35_FWM-M14.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" Rusty, 4130 is simply a better material for an engine mount. Lynn's comments were pretty much on point, 4130 is stronger, harder and much tougher. Stainless usually only is truly rust resistant if passivated or electropolished after welding. The welding process brings some of the iron to the surface and the area around the weld will rust in the area of discoloration. Stainless is VERY subject to hydrogen embrittlement too. This can cause cracking on welded structures used in vibrating assemblys. 4130 isn't as subject to H2 embrittlement. So there are lots of reasons to use 4130. If the structure is suitably overbuilt this might not be a problem, but you better be sure of that. A engine mount failure is a VERY BAD thing on a autogyro. Bill Jepson -----Original Message----- From: rijakits@cwpanama.net To: flyrotary@lancaironline.net Sent: Wed, 28 Feb 2007 8:35 AM Subject: [FlyRotary] Re: engine mount 4130 vs 304 SS Ernest, """> Thomas, I don't see the benefit of stainless being the protection of the > inside of the tube......"""" I don't like stainless at all , unless there is no workable alternative... Rusty wants the bling on the thing!! Thomas -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ________________________________________________________________________ AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com. ----------MB_8C92970F89AC702_1F74_1C35_FWM-M14.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/html; charset="us-ascii"

Rusty,

4130 is simply a better material for an engine mount. Lynn's comments were pretty much on point, 4130 is stronger, harder and much tougher. Stainless usually only is truly rust resistant if passivated or electropolished after welding. The welding process brings some of the iron to the surface and the area around the weld will rust in the area of discoloration. Stainless is VERY subject to hydrogen embrittlement too. This can cause cracking on welded structures used in vibrating assemblys. 4130 isn't as subject to H2 embrittlement. So there are lots of reasons to use 4130. If the structure is suitably overbuilt this might not be a problem, but you better be sure of that. A engine mount failure is a VERY BAD thing on a autogyro.

Bill Jepson

-----Original Message-----
From: rijakits@cwpanama.net
To: flyrotary@lancaironline.net
Sent: Wed, 28 Feb 2007 8:35 AM
Subject: [FlyRotary] Re: engine mount 4130 vs 304 SS

Ernest,

"""> Thomas, I don't see the benefit of stainless being the protection of the
> inside of the tube......""""

I don't like stainless at all , unless there is no workable alternative...

Rusty wants the bling on the thing!!

Thomas
--
Homepage: http://www.flyrotary.com/
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