X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4218502 for flyrotary@lancaironline.net; Mon, 12 Apr 2010 10:24:17 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao106.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20100412142341.WYRH1296.fed1rmmtao106.cox.net@fed1rmimpo01.cox.net> for ; Mon, 12 Apr 2010 10:23:41 -0400 Received: from BigAl ([72.192.128.205]) by fed1rmimpo01.cox.net with bizsmtp id 4ePh1e0034S1t5C03ePh4P; Mon, 12 Apr 2010 10:23:41 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.1 cv=3rYd4LfcKLU522ZHXfO06E856SAcXud2pffNCWjpFlA= c=1 sm=1 a=PyNjkaOVL4wA:10 a=Vegc0WxVmH5BHtpNDyThtA==:17 a=7g1VtSJxAAAA:8 a=Ia-xEzejAAAA:8 a=pNCjowhErogc2QvCVw4A:9 a=7_cdmCRwb8CPCNZvD9EA:7 a=wa18xUh0j_5839TyibIaC7cG2ukA:4 a=CjuIK1q_8ugA:10 a=Qa1je4BO31QA:10 a=PE3VIgARqoyORcGwxZkA:9 a=N7JgXpnV6h_3jc6U0WgA:7 a=rKLBTAxsDDCgHTGkPmyUJTkxTI8A:4 a=Vegc0WxVmH5BHtpNDyThtA==:117 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Tangential muffler Date: Mon, 12 Apr 2010 07:24:07 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0021_01CADA11.236B8A70" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6856 Thread-Index: AcraQDZ2Ir7/Urr2T1WzOVdbc3RkMAAEcFUg X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0021_01CADA11.236B8A70 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable =20 =20 Ernest; =20 I agree that the geometry of the geometry of the cuts is certainly not ideal; and if it were 321SS or similar; yes, I'd expect it would it to disintegrate in about 50 hrs or less. But inconel is very corrosion resistant and very strong up to 2000+F. There will be some = self-annealing of the stresses at 1700F. It would be interesting to know what temp it actually gets to because there is some expansion cooling of the gases in = the muffler. =20 Also it is very tough stuff - trying to drill or file inconel will just = wear out the tools. Holes have to be punched, cut with water jet, or some = other technique. =20 It will be interesting to see how it stands up; but I think it has a = good chance to prove to be quite durable. =20 Al =20 A grinder will leave two fairly severe 90 degree corners on every edge=20 of the cut slot. Compounding this is the fact that the side grinder=20 cuts a circle. The end of each slot will be left with a knife edge=20 profile pointing back toward the slot. This will create some mean=20 stress risers. The expectation is that this tube is to live in an=20 environment that has to be the closest thing to hell on Earth we could=20 imagine (extreme heat and constant sonic blasts). =20 I would have suggested drilling 3/16" holes and connecting them with the = grinder. Unless the inside tube is fabricated different than what I=20 understand, I can't help but to think that it will have a very short=20 life. Cracks will start in the corners of each slot, and the tube will=20 disintegrate. Can it be easily pulled apart so that you could run a=20 round needle file down both sides of all the slots to round them out? =20 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_0021_01CADA11.236B8A70 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Ernest;

I agree that the geometry of the geometry of the = cuts is certainly not ideal; and if it were 321SS or similar; yes, I’d = expect it would it to disintegrate in about 50 hrs or less. But inconel is = very corrosion resistant and very strong up to 2000+F. There will be = some self-annealing of the stresses at 1700F. It would be interesting = to know what temp it actually gets to because there is some expansion cooling of = the gases in the muffler.

Also it is very tough stuff – trying to drill = or file inconel will just wear out the tools. Holes have to be punched, = cut with water jet, or some other technique.

It will be interesting to see how it stands up; but = I think it has a good chance to prove to be quite = durable.

Al

A grinder will leave two fairly severe 90 degree corners on every edge =

of the cut slot. Compounding this is the fact that the side grinder =

cuts a circle. The end of each slot will be left with a knife edge =

profile pointing back toward the slot. This will create some mean =

stress risers. The expectation is that this tube is to live in an =

environment that has to be the closest thing to hell on Earth we could =

imagine (extreme heat and constant sonic blasts).

I would have suggested drilling 3/16" holes and connecting them with = the

grinder. Unless the inside tube is fabricated different than what I =

understand, I can't help but to think that it will have a very short =

life. Cracks will start in the corners of each slot, and the tube will =

disintegrate. Can it be easily pulled apart so that you could run a

round needle file down both sides of all the slots to round them = out?

--

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

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