X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from vms040pub.verizon.net ([206.46.252.40] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1316742 for flyrotary@lancaironline.net; Wed, 26 Jul 2006 10:37:28 -0400 Received: from verizon.net ([71.99.146.116]) by vms040.mailsrvcs.net (Sun Java System Messaging Server 6.2-4.02 (built Sep 9 2005)) with ESMTPA id <0J3000JAGLXZOXT9@vms040.mailsrvcs.net> for flyrotary@lancaironline.net; Wed, 26 Jul 2006 09:37:11 -0500 (CDT) Date: Wed, 26 Jul 2006 10:37:03 -0400 From: Finn Lassen Subject: Re: [FlyRotary] Re: Joe Hull's OSH Trip - Part 2 In-reply-to: To: Rotary motors in aircraft Message-id: <44C77E0F.8070505@verizon.net> MIME-version: 1.0 Content-type: multipart/alternative; boundary=------------010304040909010001060109 X-Accept-Language: en-us, en References: User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax; PROMO) This is a multi-part message in MIME format. --------------010304040909010001060109 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Ground running won't necessarily get you into that thermo cycle range. Seems you consistently have to get above 5,000 RPM before anything happens. No expansion joints: it will crack. Unless you use ridiculously thick material. Which is probably why the stock Mazda manifold is so heavy. Finn Bob White wrote: >Hi Joe, > >Great story. Glad you were on top of everything and made the right >decisions. > >I have a similar exhaust system I think. Two short tubes into a large >can. On mine, the short tubes are 0.065 321 SS. After 5 hours of ground >running there doesn't appear to be any deterioration, but it's >definitely something to keep an eye on. Which was made more difficult >by the insulation I just added. I think I will install one of my >'J'Thermocouples on the insulation just above the exhaust system. That >temp should spike if there is any crack in the exhaust. I also have >cool air flowing thru the center of the can but so far I haven't seen >much flow because of the low speed operations. A lot of hot air flow >out after shutdown though. > >Thanks for a great report. Maybe we should plan a rotary fly-in at >Hyannis, Nebraska. :) How many rooms did that hotel have? > >Bob W. > > >On Tue, 25 Jul 2006 21:55:08 -0700 >"Joe Hull" wrote: > > > >>>You definitely need expansion joints. Tubes sliding within tubes, or >>>some other type of flex joints. >>>The thermal expansion/contraction simply kills those short runners. >>> >>>Finn >>> >>> >>Yep, I'm re-doing the whole exhaust system. No more inconel and no more >>tangential collector. It's probably going to be 2" x .065 wall, 321 >>Stainless tubes going to a collector and muffler of some sort. I seriously >>like the idea of non-welded joints - nothing to break off! >> >>Joe Hull >>Cozy Mk-IV N31CZ (65 hrs - Rotary 13B NA) >>Redmond (Seattle), Washington >> >> >> >>-- >>Homepage: http://www.flyrotary.com/ >>Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ >> >> > > > > --------------010304040909010001060109 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Ground running won't necessarily get you into that thermo cycle range. Seems you consistently have to get above 5,000 RPM before anything happens.

No expansion joints: it will crack.
Unless you use ridiculously thick material. Which is probably why the stock Mazda manifold is so heavy.

Finn

Bob White wrote:

Hi Joe,

Great story.  Glad you were on top of everything and made the right
decisions.

I have a similar exhaust system I think.  Two short tubes into a large
can. On mine, the short tubes are 0.065 321 SS.  After 5 hours of ground
running there doesn't appear to be any deterioration, but it's
definitely something to keep an eye on.  Which was made more difficult
by the insulation I just added.  I think I will install one of my
'J'Thermocouples on the insulation just above the exhaust system.  That
temp should spike if there is any crack in the exhaust.  I also have
cool air flowing thru the center of the can but so far I haven't seen
much flow because of the low speed operations.  A lot of hot air flow
out after shutdown though.

Thanks for a great report.  Maybe we should plan a rotary fly-in at
Hyannis, Nebraska. :)  How many rooms did that hotel have?

Bob W.


On Tue, 25 Jul 2006 21:55:08 -0700
"Joe Hull" <joeh@pilgrimtech.com> wrote:

You definitely need expansion joints. Tubes sliding within tubes, or
some other type of flex joints.
The thermal expansion/contraction simply kills those short runners.

Finn

Yep, I'm re-doing the whole exhaust system. No more inconel and no more
tangential collector.  It's probably going to be 2" x .065 wall, 321
Stainless tubes going to a collector and muffler of some sort. I seriously
like the idea of non-welded joints - nothing to break off!

Joe Hull
Cozy Mk-IV N31CZ (65 hrs - Rotary 13B NA) 
Redmond (Seattle), Washington



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