X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-pd0-f175.google.com ([209.85.192.175] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6702842 for flyrotary@lancaironline.net; Sat, 25 Jan 2014 21:14:27 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.192.175; envelope-from=wdleonard@gmail.com Received: by mail-pd0-f175.google.com with SMTP id w10so4458923pde.6 for ; Sat, 25 Jan 2014 18:13:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=nCAhGoqgjAG5sJvJOSE9McOJTToOU32e2qL5P+LiBaw=; b=KXT9rUmm4JsFLakrIAH98JMifdkQkBUdE3L5GfkJRHTtjp+v4V7GpgkfwpdrfioBNH VJeNJoaMt21fZwUTqdMK1woXSEmQ729US+RB9s0J0j1Ysx5hil/CDBKgziHpKvEm+gfv LjWnd8WD9giPPZHJeHq9dKyCKHZVMTYTueHvFbqooV4l4hQvbjP5QcDP6KddAv+0Goe1 MHhxgJRzk/fgBgquSeNY2dBx38QbFmyw52t3W6EuxrPRtM6rBTciQ8uSiDzESYTYwvHl mbGQlxjrpk55IYrUDQ7lO0LIaITpF3Woh0pE1yEIScaYNGTUf8Va6RXdapMPBK/yr6EN BNpw== MIME-Version: 1.0 X-Received: by 10.68.198.97 with SMTP id jb1mr22653697pbc.104.1390702433165; Sat, 25 Jan 2014 18:13:53 -0800 (PST) Received: by 10.70.90.239 with HTTP; Sat, 25 Jan 2014 18:13:53 -0800 (PST) In-Reply-To: References: Date: Sat, 25 Jan 2014 18:13:53 -0800 Message-ID: Subject: Re: [FlyRotary] Re: Exhaust Leak at Turbo Outlet Flange From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=047d7bdc9e3c8466d104f0d62448 --047d7bdc9e3c8466d104f0d62448 Content-Type: text/plain; charset=ISO-8859-1 Bummer! Glad you are safe. I use the stock steel nuts. Locknuts might be an improvement but not if there is any non-steel component. I did loose one of those nuts once without to-do. Not sure how long it was gone. The other 2 held everyting together. Be very careful with what gaskets you choose. I found some nice-looking aftermarket turbo manifold gaskets for about $20 while the stock versions are about $90 each, so I installed one. It lasted about 30 hours until it disintigrated. The resulting exhaust leak burned through a coolant line and I dead sticked onto a local airport (departing from a formation routine at an airshow!.. complete with a cloud of steam). Sigh, the stock ones are nothing but stainless steel layer, not some sort of fiber stuff in the after market ones. On another occasion I was using some very nice and expensive exhaust clamps that were steel but I didnt notice that part of the block holding the nuts was aluminum. About 50 hrs in something caused the alumimum to get too hot, which created an exhaust leak, which accelerated the process. It burned a hole in the cowl and splatered molten aluminum everywhere - some of it is still around. Another time I was using some fancy exhaust wrap. It slowly disintigrated over the course of 100+ hours and was generally an annoyance. I tried a flowmaster hushpower muffler but melted most of the stuffing out of it on the first flight. Luckily it melted pretty cleanly and didnt clog the exhaust. Moral of the story.. as if it didn't take me long enough to beat this through my skull.. NOTHING that is not made of steel or better goes into any part of the exhaust system. Particularly gaskets and nuts. Guess I should have passed that one along sooner. Glad you got back safely. Good job. Dave Leonard On Sat, Jan 25, 2014 at 5:14 PM, wrote: > > > I had the nuts come loose on my turbo manifold on the block, I'm using > with out the turbo, so I drilled the nuts and secured them with wire. JohnD > > Thanks for keeping us all informed , helps us all to make sure we look for > often simple overlooked areas. > > Cheers > Christian > Renises 13 b rv7 > > Sent from my iPad > > On 26/01/2014, at 3:17 AM, shipchief@aol.com wrote: > > During the 8th flight of my RV8 with 13B Turbo, I experienced an > exhaust leak at the turbo exhaust flange. I mistakenly used brass exhaust > nuts which are twice as tall as regular nuts. They work great on most > engines. I should have know better, as the temperature at the turbo outlet, > under the insulation is much higher. > The brass nuts softened and deformed into a flange face at the washer! > Once the tension was gone, the heat & vibration did the rest. > The exhaust gasket blew where the gap was widest, at the top. > The escaping heat burned thru the insulating jacket and the stick on > reflective aluminum. Then the fiberglass cowl charred, I smelled that! > I was close to my destination, and high, so I was able to pull off the > power, put down the nosed and get on the ground without incident. > I'm disassembling it now, looks like I need 4 high temperature lock nuts > and a TO-4 exhaust flange gasket. I should review and improve the > insulation over the turbine housing. Also I need to repair the charred area > of the cowl, which might be in the form of an aluminum access hatch. > > --047d7bdc9e3c8466d104f0d62448 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Bummer!=A0 Glad you are safe.
=A0
I use the stock steel nuts.=A0 Locknuts might be an improvement but no= t if there is any non-steel component.=A0 I did loose one of those nuts onc= e without to-do.=A0 Not sure how long it was gone.=A0 The other 2 held ever= yting together.
=A0
Be very careful with what gaskets you choose.=A0 I found some nice-loo= king aftermarket turbo manifold gaskets for about $20 while the stock versi= ons are about $90 each, so I installed one.=A0 It lasted about 30 hours unt= il it disintigrated.=A0 The resulting exhaust leak burned through a coolant= line and I dead sticked onto a local airport (departing from=A0a formation= routine at an airshow!..=A0 complete with a cloud of steam).
=A0
Sigh,=A0the stock ones are nothing but stainless steel layer, not some= sort of fiber stuff in the after market ones.=A0
=A0
On another occasion I was using some very nice and expensive exhaust c= lamps that were steel but I didnt notice that part of the block holding the= nuts was aluminum.=A0 About 50 hrs in something caused the alumimum to get= too hot, which created an exhaust leak, which accelerated the process.=A0 = It burned a hole in the cowl and splatered molten aluminum everywhere - som= e of it is still around.
=A0
Another time I was using=A0some fancy exhaust wrap.=A0 It slowly disin= tigrated over the course of 100+ hours and was generally an annoyance.
=A0
I tried a flowmaster hushpower muffler but melted most of=A0the stuffi= ng out of it on the first flight. Luckily it melted pretty cleanly and didn= t clog the exhaust.
=A0
Moral of the story..=A0 as if it didn't take me long enough to bea= t this=A0through my skull..=A0 NOTHING that is not made of steel or better = goes into any part of the exhaust system.=A0 Particularly gaskets and nuts.=
=A0
Guess I should have passed that one along sooner.=A0 Glad you got back= safely.=A0 Good job.
=A0
Dave Leonard

On Sat, Jan 25, 2014 at 5:14 PM, <downing= .j@sbcglobal.net> wrote:
=A0
I had the nuts come loose on my turbo manifo= ld=A0on the block,=A0I'm using with out the turbo, so I drilled the nut= s and secured them with wire.=A0 JohnD

Thanks for keeping us all informed , helps us all to make sure we look= for often simple overlooked areas.

Cheers
Christian=A0
Renises 13 b rv7

Sent from my iPad

On 26/01/2014, at 3:17 AM, shipchief@aol.com wrote:

During the 8th flight of = my RV8 with 13B Turbo, I experienced an exhaust leak at the turbo exhaust f= lange. I mistakenly used brass exhaust nuts=A0 which are twice as tall as r= egular nuts. They work great on most engines. I should have know better, as= the temperature at the turbo outlet, under the insulation is much higher.<= /font>
The brass nuts softened and deformed into a flange face at the washer!= Once the tension was gone, the heat & vibration did the rest.
The exhaust gasket blew where the gap was widest, at the top.
The escaping heat burned thru the insulating jacket=A0and the stick on= reflective aluminum.=A0Then=A0the fiberglass cowl=A0charred, I smelled tha= t!
I was close to my destination, and high, so I was able to pull off the= power, put down the nosed and get on the=A0ground without incident.
I'm disassembling it=A0now, looks like I need 4 high temperature l= ock nuts and a TO-4 exhaust flange gasket. I should review and improve the = insulation over the turbine housing. Also I need to repair the charred area= of the cowl, which might be in the form of an aluminum access hatch.

--047d7bdc9e3c8466d104f0d62448--