X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta09-srv.windstream.net ([166.102.165.170] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2463536 for flyrotary@lancaironline.net; Fri, 09 Nov 2007 11:45:10 -0500 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.170; envelope-from=montyr2157@alltel.net Received: from ispmxaamta04-gx.windstream.net ([151.213.143.21]) by ispmxmta09-srv.windstream.net with ESMTP id <20071109164429.KKXX21683.ispmxmta09-srv.windstream.net@ispmxaamta04-gx.windstream.net> for ; Fri, 9 Nov 2007 10:44:29 -0600 Received: from Thorstwin ([151.213.143.21]) by ispmxaamta04-gx.windstream.net with SMTP id <20071109164429.GRUP8365.ispmxaamta04-gx.windstream.net@Thorstwin> for ; Fri, 9 Nov 2007 10:44:29 -0600 Message-ID: <002501c822ef$ce32e830$6501a8c0@Thorstwin> From: "M Roberts" To: "Rotary motors in aircraft" Subject: Re: Spin Tech Date: Fri, 9 Nov 2007 10:44:33 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01C822BD.83797E80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0022_01C822BD.83797E80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, Is there any consensus at this time as to which alloy (304 or 409) is = the most=20 durable for our hot breathed 13B rotarys ?? -- Kelly Troyer=20 "Dyke Delta"_13B ROTARY Engine=20 "RWS"_RD1C/EC2/EM2=20 "Mistral"_Backplate/Oil Manifold=20 Kelly, I'm not Ed but I did sleep at a Holiday Inn Express!! Alloys to use for Rotary engine exhaust in order of decreasing = desirability (and cost) 1.) Inconel 2.) 321 Stainless 3.) 304 Stainless 4.) 409 Stainless 5.) Mild steel Basically 409 is a low chromium stainless designed for the automotive = market, specifically for exhaust tubing. It does not polish well and = will develop a protective coating of rust. It will live just fine, but = will be less attractive. If you move up in cost you get a higher chromium and nickel content and = therefore a higher temp resistance and creep resistance. This means you = can make everything lighter and thinner. Of course it becomes much more = important to properly design the manifold for expansion/thermal cycling = loads the thinner it gets. So you will have to put a lot of slip joints = and metal bellows in it to seal it up if it is a turbo installation. = So.....how much do you want to spend to save 5 lbs or have a polished = tail pipe is the question. Mild steel will work fine if it is thick enough. Especially if you coat = it with ceramic. I suppose you could also coat the 409 stainless with = ceramic if you want a nice finish, but it might be less expensive to = just use 304 at that point. Monty ------=_NextPart_000_0022_01C822BD.83797E80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Ed,

Is there any consensus at this = time as to=20 which alloy (304 or 409) is the most

durable for our hot breathed 13B = rotarys=20 ??

--
Kelly Troyer=20
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2=20
"Mistral"_Backplate/Oil Manifold

Kelly,

I'm = not Ed but I did=20 sleep at a Holiday Inn Express!!

Alloys to use for=20 Rotary engine exhaust in order of decreasing desirability (and=20 cost)

1.)=20 Inconel

2.) = 321=20 Stainless

3.) = 304=20 Stainless

4.) = 409=20 Stainless

5.) = Mild=20 steel

Basically 409 is a=20 low chromium stainless designed for the automotive market, specifically = for=20 exhaust tubing. It does not polish well and will develop a protective = coating of=20 rust. It will live just fine, but will be less attractive.

If = you move up in=20 cost you get a higher chromium and nickel content and therefore a higher = temp=20 resistance and creep resistance. This means you can make everything = lighter and=20 thinner. Of course it becomes much more important to properly design the = manifold for expansion/thermal cycling loads the thinner it gets. = So you=20 will have to put a lot of slip joints and metal bellows in it to seal it = up if=20 it is a turbo installation. So.....how much do you want to spend to save = 5 lbs=20 or have a polished tail pipe is the question.

Mild = steel will work=20 fine if it is thick enough. Especially if you coat it with ceramic. I = suppose=20 you could also coat the 409 stainless with ceramic if you want a nice = finish,=20 but it might be less expensive to just use 304 at that = point.

Monty =

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