X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [216.211.128.10] (HELO mail-in03.adhost.com) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 999828 for flyrotary@lancaironline.net; Mon, 27 Feb 2006 10:48:02 -0500 Received-SPF: none receiver=logan.com; client-ip=216.211.128.10; envelope-from=joeh@pilgrimtech.com Received: from Pilgrim10 (tide515.microsoft.com [131.107.0.85]) by mail-in03.adhost.com (Postfix) with ESMTP id 30BDF2A7E13 for ; Mon, 27 Feb 2006 07:46:57 -0800 (PST) (envelope-from joeh@pilgrimtech.com) From: "Joe Hull" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Exhaust Blowout Date: Mon, 27 Feb 2006 07:46:57 -0800 Message-ID: <002401c63bb5$0c5a9460$cda0389d@redmond.corp.microsoft.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0025_01C63B71.FE375460" X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2670 In-Reply-To: Thread-Index: AcY7kzo9OV6cfVv2TxCOh8CLJW2nKwAH5QwQ This is a multi-part message in MIME format. ------=_NextPart_000_0025_01C63B71.FE375460 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanx for the responses everyone. =20 The solution we came up with yesterday was as follows: Since the = original =93figure 8=94 profile was made out of two 2 =BD=94 tubes that we cut = slots out of it seems the best way to get a web across the center is to take off one = of the halves and replace it with a complete and uncut 2 =BD tube. I had = some tube left from the original construction and that=92s what we did last = night. Now we need to find someone to weld it all up. All we (really not = =93we=94 but my friend) tack welded it in place. But he was having real trouble = getting it to weld and not just burn through. So we need to find a good welder = that can deal with finicky material. The original welder is a real pro =96 so = we=92re going to see if he has any availability. =20 BTW the end caps on the tangential can are .060 inconel. Anyone have an opinion on whether those will survive. At the time I built the exhaust everyone I talked to seemed to think that .035 or higher would be good enough =96 that=92s why I essentially doubled the thickness. =20 =20 I may also just put on a stock exhaust manifold. I=92ve got one so the = price is right! Since I took the opportunity to remove my second alternator = while I was tearing out the exhaust system I=92ve got enough weight savings = that I can afford the heavier manifold. But of course that will mean a change = to the cowling - ARRGGGHHH! The poor cowling has been cut up and put back together so many times it looks like a patchwork quilt on the inside = where there isn=92t any paint! =20 Joe Hull Cozy Mk-IV #991 (Done Building! In Phase1 Flight Test - 0 hrs flown)=20 Redmond (Seattle), Washington =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Steve Brooks Sent: Monday, February 27, 2006 3:49 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Exhaust Blowout =20 Joe, Sorry to hear about your muffler. Better that it happened on the ground though. Do you have a solution for the problem ? =20 Steve Brooks =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Joe Hull Sent: Monday, February 27, 2006 2:10 AM To: Rotary motors in aircraft Subject: [FlyRotary] Exhaust Blowout I'm still struggling with tuning my rotary/microtech. I spent an hour or = so running it yesterday and ended up a little closer on the tuning front = but also ended up with a blown out exhaust/muffler. It's come apart at a = bunch of places - not the welds but the Inconel itself next to the welds. =20 The exhaust pipe coming out of the "tangential tube" is/was in the = profile of an "8" without the connection in the center. An engineer friend of = mine who looked it over said it makes sense - after the fact - that the = exhaust pulses were causing the tube to flex at the center joint. It appears to have started at the outboard end and went all the way to the center tube = and then, perhaps from vibration, cracked out the pipes except for about = =BD" from the center connection. =20 The main manifold - runners and the tangential tube - are all sound with = no signs of stress. So, be careful out there! =20 Pics attached. =20 Thanx, Joe Hull Cozy Mk-IV #991 (Done Building! In Phase1 Flight Test - 0 hrs flown)=20 Redmond (Seattle), Washington ------=_NextPart_000_0025_01C63B71.FE375460 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Thanx for the responses = everyone.

 

The solution we came up with = yesterday was as follows: Since the original “figure 8” profile was made = out of two 2 =BD” tubes that we cut slots out of it seems the best way to = get a web across the center is to take off one of the halves and replace it = with a complete and uncut 2 =BD tube.=A0 I had some tube left from the original = construction and that’s what we did last night.=A0 Now we need to find someone = to weld it all up. All we (really not “we” but my friend) tack = welded it in place. But he was having real trouble getting it to weld and not just = burn through. So we need to find a good welder that can deal with finicky = material. The original welder is a real pro – so we’re going to see if = he has any availability.

 

BTW the end caps on the tangential = can are .060 inconel.=A0 Anyone have an opinion on whether those will survive. = At the time I built the exhaust everyone I talked to seemed to think that .035 = or higher would be good enough – that’s why I essentially = doubled the thickness.=A0

 

I may also just put on a stock = exhaust manifold. I’ve got one so the price is right! Since I took the opportunity to remove my second alternator while I was tearing out the = exhaust system I’ve got enough weight savings that I can afford the = heavier manifold. But of course that will mean a change to the cowling - = ARRGGGHHH!=A0 The poor cowling has been cut up and put back together so many times it = looks like a patchwork quilt on the inside where there isn’t any = paint!

 

Joe = Hull

Cozy Mk-IV #991 (Done Building! In = Phase1 Flight Test - 0 hrs flown)

Redmond (Seattle), Washington

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Steve Brooks
Sent: Monday, February = 27, 2006 3:49 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Exhaust Blowout

 

Joe,

Sorry to hear about your = muffler.  Better that it happened on the ground though.  Do you have a = solution for the problem ?

 

Steve = Brooks

 

-----Original = Message-----
From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net]On Behalf Of Joe Hull
Sent: Monday, February = 27, 2006 2:10 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Exhaust Blowout

I'm still struggling with tuning my rotary/microtech. = I spent an hour or so running it yesterday and ended up a little closer on = the tuning front but also ended up with a blown out exhaust/muffler. It's = come apart at a bunch of places - not the welds but the Inconel itself next = to the welds.

 

The exhaust pipe coming out of the "tangential tube" is/was in the profile of an "8" without the = connection in the center. An engineer friend of mine who looked it over said it makes = sense - after the fact - that the exhaust pulses were causing the tube to flex = at the center joint.  It appears to have started at the outboard end and = went all the way to the center tube and then, perhaps from vibration, cracked out = the pipes except for about =BD" from the center = connection.

 

The main manifold - runners and the tangential tube - = are all sound with no signs of stress.

So, be careful out = there!

 

Pics attached.

 

Thanx,

Joe Hull

Cozy Mk-IV #991 (Done Building! In Phase1 Flight Test = - 0 hrs flown)

Redmond (Seattle), = Washington

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