X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m14.mx.aol.com ([64.12.138.204] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 999715 for flyrotary@lancaironline.net; Mon, 27 Feb 2006 08:52:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.204; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m14.mx.aol.com (mail_out_v38_r7.3.) id q.233.7995cce (25711) for ; Mon, 27 Feb 2006 08:51:33 -0500 (EST) From: Lehanover@aol.com Message-ID: <233.7995cce.31345de5@aol.com> Date: Mon, 27 Feb 2006 08:51:33 EST Subject: Re: [FlyRotary] Exhaust Blowout To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1141048293" X-Mailer: 9.0 SE for Windows sub 5022 X-Spam-Flag: NO -------------------------------1141048293 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en =20 In a message dated 2/27/2006 2:12:01 AM Eastern Standard Time, =20 joeh@pilgrimtech.com writes: The exhaust pipe coming out of the =E2=80=9Ctangential tube=E2=80=9D is/was= in the profile=20 of an =E2=80=9C8=E2=80=9D without the connection in the center. An engineer= friend of mine=20 who looked it over said it makes sense - after the fact - that the exhaust=20 pulses were causing the tube to flex at the center joint. It appears to ha= ve=20 started at the outboard end and went all the way to the center tube and the= n,=20 perhaps from vibration, cracked out the pipes except for about =C2=BD=E2= =80=9D from the=20 center connection.=20 The main manifold =E2=80=93 runners and the tangential tube =E2=80=93 are a= ll sound with no=20 signs of stress.=20 So, be careful out there! I have several sets of Indy CART turbo race car headers, also Inconel. They= =20 were $15.00 a set. They are discarded after three heat cycles. Because they=20= =20 fatigue quickly. They hold strength at very high temps, better than any =20 material. But not very long. They are very thin walled and fail in bending =20= readily.=20 =20 The bends are formed from sheet stock in a die. The two halves are welded =20 together. This is so no stretching of the sheet stock can make it thinner. =20 So no shape that allows pressure pulses to move material around will =20 survive. The flat end caps will need to be conical or hemispherical. A web=20= must be=20 installed between the pipes. =20 Even a flattened tube end will have to be webbed in several places to last =20 very long at all. =20 The welds are thicker and more stable, so a stress riser forms beside each =20 weld. =20 Or, make it out of stainless. =20 I had made up primary header tubes from .130" wall mild steel tubing. I =20 wrapped the bends with insulation. The outside of the bends turned to dust.=20= Let a=20 little air blow on the same tube bends without insulation, and they last for= =20 years.=20 =20 Lynn E. Hanover =20 -------------------------------1141048293 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
In a message dated 2/27/2006 2:12:01 AM Eastern Standard Time,=20 joeh@pilgrimtech.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>

The exhaust pipe coming out=20= of the=20 =E2=80=9Ctangential tube=E2=80=9D is/was in the profile of an =E2=80=9C8= =E2=80=9D without the connection in=20 the center. An engineer friend of mine who looked it over said it makes se= nse=20 - after the fact - that the exhaust pulses were causing the tube to flex a= t=20 the center joint.  It appears to have started at the outboard end and= =20 went all the way to the center tube and then, perhaps from vibration, crac= ked=20 out the pipes except for about =C2=BD=E2=80=9D from the center=20 connection.

 

The main manifold =E2=80=93=20= runners and=20 the tangential tube =E2=80=93 are all sound with no signs of=20 stress.

So, be careful out=20 there!

I have several sets of Indy CART turbo race car headers, also Inco= nel.=20 They were $15.00 a set. They are discarded after three heat cycles. Because=20= they=20 fatigue quickly. They hold strength at very high temps, better than any=20 material. But not very long. They are very thin walled and fail in bending=20 readily.
 
The bends are formed from sheet stock in a die. The two halves are weld= ed=20 together. This is so no stretching of the sheet stock can make it thinner.
 
So no shape that allows pressure pulses to move material around wi= ll=20 survive.  The flat end caps will need to be conical or hemispherical. A= web=20 must be installed between the pipes.
 
Even a flattened tube end will have to be webbed in several places to l= ast=20 very long at all.
 
The welds are thicker and more stable, so a stress riser forms beside e= ach=20 weld.
 
Or, make it out of stainless.
 
I had made up primary header tubes from .130" wall mild steel tubing. I= =20 wrapped the bends with insulation. The outside of the bends turned to dust.=20= Let=20 a little air blow on the same tube bends without insulation, and they last f= or=20 years. 
 
Lynn E. Hanover  
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