X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1912159 for flyrotary@lancaironline.net; Fri, 09 Mar 2007 18:09:31 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=rotaryrx6@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao102.cox.net (InterMail vM.7.05.02.00 201-2174-114-20060621) with ESMTP id <20070309230840.PWLL28911.fed1rmmtao102.cox.net@fed1rmimpo02.cox.net> for ; Fri, 9 Mar 2007 18:08:40 -0500 Received: from cox.net ([72.193.26.4]) by fed1rmimpo02.cox.net with bizsmtp id Yn8X1W00B05JoQg0000000; Fri, 09 Mar 2007 18:08:40 -0500 Message-ID: <45F1E954.8298BEB7@cox.net> Date: Fri, 09 Mar 2007 15:10:12 -0800 From: Doug X-Mailer: Mozilla 4.75 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] engine mount 4130 vs 304 SS References: Content-Type: multipart/alternative; boundary="------------FD3419DAE628DEAA4DA0601A" --------------FD3419DAE628DEAA4DA0601A Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi Rusty, yes, 304 stainless is more difficult to weld and the material is more brittle. Not that any of these traits can be overcome but 4130 is just plain more durable and forgiving. That is why it has been used in aviation for so long. Welding stainless properly is an art. Weld pool contamination is generally the most common problem. If you can shield the other side of the weld pool from the atmosphere you will have great success is weld strength. Doug Mueller RX-6 13BT N900DM Boulder City, NV Russell Duffy wrote: > Greetings,As I ponder my choices for mounting the single rotor > engine, I noticed something that surprised me. 304 stainless is > cheaper than 4130 steel. One thing that's always bothered me about > steel tube type construction is the concern for rusting inside the > tubes, so stainless is appealing. There must be a catch here. Is > there a good reason I should use 4130 instead of 304? Either will > likely be sized much larger than needed, since I don't have the means > to do any proper analysis of the strength. Thanks,Rusty (Autoflight > drive supposed to be shipping next week) --------------FD3419DAE628DEAA4DA0601A Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Hi Rusty, yes, 304 stainless is more difficult to weld and the material is more brittle. Not that any of these traits can be overcome but 4130 is just plain more durable and forgiving. That is why it has been used in aviation for so long. Welding stainless properly is an art. Weld pool contamination is generally the most common problem. If you can shield the other side of the weld pool from the atmosphere you will have great success is weld strength.
Doug Mueller
RX-6 13BT
N900DM
Boulder City, NV

Russell Duffy wrote:

Greetings,As I ponder my choices for mounting the single rotor engine, I noticed something that surprised me. 304 stainless is cheaper than 4130 steel. One thing that's always bothered me about steel tube type construction is the concern for rusting inside the tubes, so stainless is appealing. There must be a catch here. Is there a good reason I should use 4130 instead of 304? Either will likely be sized much larger than needed, since I don't have the means to do any proper analysis of the strength. Thanks,Rusty (Autoflight drive supposed to be shipping next week)

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