X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 87 [XXXX] (25%) RECEIVED: IP not found on home country list (25%) OBFUSCATED_WORD1_BILLS (25%) BODY: contains unusually quoted characters (13%) BODY: text/html email has no html tag (13%) BODY: content type is strictly "text/html" X-Alert: possible spam! X-Color: red Return-Path: Received: from misav09.sasknet.sk.ca ([142.165.20.173] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1876026 for flyrotary@lancaironline.net; Thu, 01 Mar 2007 08:26:22 -0500 Received-SPF: none receiver=logan.com; client-ip=142.165.20.173; envelope-from=hjjohnson@sasktel.net Received: from bgmpomr1.sasknet.sk.ca ([142.165.72.22]) by misav09 with InterScan Messaging Security Suite; Thu, 01 Mar 2007 07:25:34 -0600 Received: from sasktel.net ([192.168.234.97]) by bgmpomr1.sasknet.sk.ca (SaskTel eMessaging Service) with ESMTP id <0JE8004GN7YM0Q10@bgmpomr1.sasknet.sk.ca> for flyrotary@lancaironline.net; Thu, 01 Mar 2007 07:25:34 -0600 (CST) Received: from [192.168.234.24] (Forwarded-For: [24.72.101.251]) by cgmail1.sasknet.sk.ca (mshttpd); Thu, 01 Mar 2007 07:25:34 -0600 Date: Thu, 01 Mar 2007 07:25:34 -0600 From: H & J Johnson Subject: Re: [FlyRotary] Re: engine mount 4130 vs 304 SS To: Rotary motors in aircraft Message-id: MIME-version: 1.0 X-Mailer: Sun Java(tm) System Messenger Express 6.1 HotFix 0.20 (built Feb 27 2006) Content-type: text/html; charset=us-ascii Content-language: en Content-transfer-encoding: 7BIT Content-disposition: inline X-Accept-Language: en Priority: normal

A couple other points [ I'm currently working through a project designin/building a 25,000lb machine from stainless] For the same strength, you'll have an increased weight [Stainless ain't light..] and there are concerns with warpage when welding. TIG would help that, but in reality.. Stainless will warp
"just 'cause it can...", Fatigue crack's would also concern me..

FWIW

Jarrett

----- Original Message -----

From: George Lendich <lendich@optusnet.com.au>

Date: Thursday, March 1, 2007 1:33 am

Subject: [FlyRotary] Re: engine mount 4130 vs 304 SS

> Rusty, I support Bill's comments.
> The only place I would use SS is in the foot controls, it has to
> be bigger and thicker than 4130.
> I love SS but wouldn't use it on any structural component -
> especially on an aircraft of any sort!
> George ( down under)
> 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
> --
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