X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-04.southeast.rr.com ([24.25.9.103] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1318346 for flyrotary@lancaironline.net; Thu, 27 Jul 2006 10:44:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-111-186.carolina.res.rr.com [24.74.111.186]) by ms-smtp-04.southeast.rr.com (8.13.6/8.13.6) with SMTP id k6REhSXO004512 for ; Thu, 27 Jul 2006 10:43:30 -0400 (EDT) Message-ID: <000901c6b18a$c2d3c720$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: ***SPAM*** [FlyRotary] Re: Exhaust pipes Date: Thu, 27 Jul 2006 10:41:35 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C6B169.3B595330" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C6B169.3B595330 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Yes, Joe, after the ball joints they join the muffler which is supported = to the fuselage Ed ----- Original Message -----=20 From: Joe Hull=20 To: Rotary motors in aircraft=20 Sent: Thursday, July 27, 2006 10:14 AM Subject: [FlyRotary] Re: ***SPAM*** [FlyRotary] Re: Exhaust pipes Ed, Are the pipes supported anywhere but at the flange? =20 Joe Hull Cozy Mk-IV N31CZ (65 hrs - Rotary 13B NA)=20 Redmond (Seattle), Washington =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Ed Anderson Sent: Thursday, July 27, 2006 5:34 AM To: Rotary motors in aircraft Subject: ***SPAM*** [FlyRotary] Re: Exhaust pipes =20 Just for another reference point, I have two 2" dia 0.11" thick = stainless Steel (304) pipes as my headers. Each header is approx 18" = long and make one 90 deg turn before exiting out the bottom of the cowl. = I now have over 400 hours running time on these headers. They were = welded by an aerospace welder who used to weld turbine blades - need I = say a great job? Since the two pipes are not attached to the same = point anywhere, any heat related expansion stress is at a minimum. =20 =20 I do use "ball joints" between the headers and the muffler tubes. =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Thursday, July 27, 2006 12:47 AM Subject: [FlyRotary] Re: Exhaust pipes =20 From the pictures of his exhaust system, it appears that the pipes = were supporting the muffler can. My understanding, is that the entire = exhaust will glow red, and the metal will soften (as in almost melt) at = high power settings. The melting point of inconel is over 2500F. Things will start to = glow at about 1000F if the light isn't too bright. It is still quite = strong at our exhaust temps. It is worth noting that one of the = features of expanding the gas into the large tube is that the = temperature drops (Charle's Law of expanding gases); the temp of the = large tube is somewhat below the temp in the header (how much lower = depends on too many factors that I don't know) and depends on = backpressure and engine rpm. =20 Al W. brings up a good point. I had been primarily considering = thermal stress, but stress due to vibration from the engine (aside from = exhaust pulses) could be a major factor. Some high frequency resonance = with engine vibration could do a job on the welds where joe's broke; or = a resonance with the unsupported exit pipe? =20 I guess I'll learn some more as I accumulate some hours on my plane. = Now a real challenge is coming up with some kind of damping support . . = . .=20 =20 Al G. ------=_NextPart_000_0006_01C6B169.3B595330 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Yes, Joe, after the ball joints they join the = muffler=20 which is supported to the fuselage
 
Ed
----- Original Message -----
From:=20 Joe Hull=20
Sent: Thursday, July 27, 2006 = 10:14=20 AM
Subject: [FlyRotary] Re: = ***SPAM***=20 [FlyRotary] Re: Exhaust pipes

Ed,

Are the = pipes=20 supported anywhere but at the flange?

 

Joe = Hull

Cozy Mk-IV N31CZ (65 hrs - = Rotary 13B NA)=20

Redmond (Seattle), Washington

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Ed Anderson
Sent: Thursday, July 27, 2006 = 5:34=20 AM
To: = Rotary motors in aircraft
Subject: ***SPAM*** [FlyRotary] = Re:=20 Exhaust pipes

 

Just for another = reference point,=20 I have two 2" dia 0.11" thick stainless Steel (304) pipes as my = headers. =20 Each header is approx 18" long and make one 90 deg turn before exiting = out the=20 bottom of the cowl.  I now have over 400 hours running time on = these=20 headers.   They were welded by an aerospace welder who used = to weld=20 turbine blades - need I say a  great job?  Since the two = pipes =20 are not  attached to the same point anywhere, any heat related = expansion=20 stress is at a minimum. 

 

I do use "ball joints" = between the=20 headers and the muffler tubes.

 

Ed

 

Ed Anderson
Rv-6A = N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.comhttp:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW

----- Original Message = -----=20

From: Al = Gietzen=20

To: Rotary motors in = aircraft=20

Sent:=20 Thursday, July 27, 2006 12:47 AM

Subject:=20 [FlyRotary] Re: Exhaust pipes

 


From the pictures of = his exhaust=20 system, it appears that the pipes were supporting the muffler = can.  My=20 understanding, is that the entire exhaust will glow red, and the = metal will=20 soften (as in almost melt) at high power=20 settings.

The = melting point=20 of inconel is over 2500F.  Things will start to glow at about = 1000F if=20 the light isn=92t too bright.  It is still quite strong at our = exhaust=20 temps.  It is worth noting that one of the features of = expanding the=20 gas into the large tube is that the temperature drops (Charle=92s = Law of=20 expanding gases); the temp of the large tube is somewhat below the = temp in=20 the header (how much lower depends on too many factors that I = don=92t know)=20 and depends on backpressure and engine = rpm.

 

Al W. = brings up a=20 good point. I had been primarily considering thermal stress, but = stress due=20 to vibration from the engine  (aside from exhaust pulses) could = be a=20 major factor.  Some high frequency resonance with  engine=20 vibration could do a job on the welds where joe=92s broke; or a = resonance with=20 the unsupported exit pipe?

 

I guess = I=92ll=20 learn some more as I accumulate some hours on my plane.  Now a = real=20 challenge is coming up with some kind of damping support . . . .=20

 

Al=20 = G.

------=_NextPart_000_0006_01C6B169.3B595330--