X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=BpPjPrf5 c=1 sm=1 tr=0 a=U+srGBIi+gSMnvSifQB1VQ==:117 a=i7nCqBWUHqtJ5GTxQztO4w==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=x7bEGLp0ZPQA:10 a=K7ySfSCCDxUA:10 a=Jdjhy38mL1oA:10 a=xPyZ54XvAAAA:8 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=jV3BzgDzAAAA:8 a=o1OHuDzbAAAA:8 a=oy0WdZRoB-guPaoOlxoA:9 a=-aUhG0MtpFPSE_v8:21 a=sw0eqI-k6FzQx7Ew:21 a=QEXdDO2ut3YA:10 a=S0wkRrzPavQA:10 a=4PR2P7QzAAAA:8 a=GgacW3ubfiaD6gfEXr8A:9 a=zy6x-jZhj1dr2Dt-:21 a=RzTSddhibmmnneZd:21 a=NrmpwNmCtbb_nKUq:21 a=LQCduUwlY3eUW_MavTj7:22 a=Urk15JJjZg1Xo0ryW_k8:22 a=9Uz93n4haClHrRxSevy5:22 a=5YQ6H4ZxyGn-KoBYtt8s:22 a=4dqwQCo7Po2mVW515mGf:22 a=pHzHmUro8NiASowvMSCR:22 a=n87TN5wuljxrRezIQYnT:22 From: "Matt Boiteau mattboiteau@gmail.com" Received: from mail-yb1-f182.google.com ([209.85.219.182] verified) by logan.com (CommuniGate Pro SMTP 6.2.14) with ESMTPS id 13423979 for flyrotary@lancaironline.net; Sat, 25 Jan 2020 20:53:40 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.182; envelope-from=mattboiteau@gmail.com Received: by mail-yb1-f182.google.com with SMTP id n66so3172618ybg.0 for ; Sat, 25 Jan 2020 17:53:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:date:message-id:subject:from:to:in-reply-to:references :user-agent; bh=1xXm126qAogOWkjuiF7FSyy2+/aBIMHvBgU2vw1W5oY=; b=lJSFD4Mrqa+Ocyjmmr1bEYWvLgDjYuEBLFWUeLd3QcUwPV9rpQGqUW4dc8+Cpl/rpd cmUAfWzJI327GPwZRSeVl7xizL52GRFi4fwU/7IxhD4MCjMmHhZAdLYt8wPRLphR1M46 ehs3hdHeC8Io37NlDfG2BaNhK/Q+pKaAzsGFLpVLuxNKg/kXuArTg6KFihvsurq8rL2Z nfh/OVRCnkdlFqQxMhBX9WZb7RvhaQidNboRfc84gItllFDMva9y07eiCtqpGeNsqFX6 pmE+I7hoLJOlYOCe1RH0Ns+OEOv5qhCTzoj8tFn172Q7rmgvLXgHP9ZwvnjYrUoPHrkZ GPhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to :in-reply-to:references:user-agent; bh=1xXm126qAogOWkjuiF7FSyy2+/aBIMHvBgU2vw1W5oY=; b=COTTlH3QXZOA10GzleYau5nAKWuqo7KHlbSaVglfb7SdUZATe2SUV2ZLe38mJoWnwP vK7tGZ7SHELPnrW1pSQnMrrHljfoShxgg+OLAA8ZoII8ikuNqAFmhRyuVoxTgD54sGxc aypNHoYk8jsC3vlq5OzxCZuOCud77uMS5bvkVvlTLcfC15cJOxtunqtvDsBS7hbaOOtF 8+vXX452nC499UZaTG7ChT7dEJWDTNe+po8wrBantw21Iq9exgU52MjTumQGlx1QoxS5 Y4QT/hZ+5cpSby4CB8NpBgcmDnKYLRp2ip4KvRWT6dgEz43IVLGQ5MqT7y5jX8/67sH8 YBYw== X-Gm-Message-State: APjAAAWjm47F/FsEjsC8laVz0INk2uIBW5iRHLMuwHvThdgmd3tjr8Ub k4O2LKIiezMYpUaE2yaRnnCqMyo8zmPvHQ== X-Google-Smtp-Source: APXvYqxRdVFwfg8BQ9mdAeAltRQj9N64aAJT0nBs5XPUh7lAC7sv0V9J7SEdM52Hdxidr1cEE3hZdg== X-Received: by 2002:a5b:c8e:: with SMTP id i14mr7373318ybq.401.1580003603375; Sat, 25 Jan 2020 17:53:23 -0800 (PST) Return-Path: Received: from [172.18.49.247] ([70.158.100.140]) by smtp.gmail.com with ESMTPSA id k5sm4592228ywa.80.2020.01.25.17.53.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 25 Jan 2020 17:53:22 -0800 (PST) Content-Type: multipart/alternative; boundary="----=_NextPart_14627015.030098822393" MIME-Version: 1.0 Date: Sat, 25 Jan 2020 20:53:22 -0500 Message-ID: <98223124-34bf-4414-935d-456c628effa5@getmailbird.com> Subject: Re: [FlyRotary] Re: Mufflers To: "Stephen Izett stephen.izett@gmail.com" In-Reply-To: <7c1cd15c-5f0d-4b93-bdcd-741997154e7f@getmailbird.com> References: <7c1cd15c-5f0d-4b93-bdcd-741997154e7f@getmailbird.com> User-Agent: Mailbird/2.5.43.0 X-Mailbird-ID: 98223124-34bf-4414-935d-456c628effa5@getmailbird.com ------=_NextPart_14627015.030098822393 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Okay so after 2 full days of having our welder out, finally brought the CAD= design to life. Except both days were all nighters, so I was too tired and= busy to take 'in progerss' pictures. Was tricky to build, which made the h= ourly welding cost sky high, more then the engine itself. Hopefully that me= ans I can save money in the future on hearing aids. Thanks Charlie for the tip on the=C2=A0spectrum analyzer. I didn't get any = before numbers, but it's all low Hz now. That harsh high pitch is gone. Db'= s are still there, but I'd say with just the muffler design, it's comparabl= e to=C2=A0typical=C2=A0lycoming. I can start to hear the prop noise over th= e engine noise. I measured back pressure around 3.5psi @ 2200rpm prop. I ran out of time to flight test the long pipe under the airplane. I quickl= y held it up with my hands and the exhaust pretty much disappeared with the= prop taking over the noise. Before flying, I want to add backpressure gaug= e to that part and drill holes to find a balance between backpressure and n= oise. SO the "header" muffler should make quite like any other plane, and the "un= der belly" pipe will make you standout in=C2=A0silence. Since this email type newsletter is from the=C2=A0dinosaur=C2=A0ages, I'll = add pictures and video=C2=A0to=C2=A0https://www.homebuiltairplanes.com/foru= ms/threads/exhaust-within-subcowl.30848/page-2#post-512762 [https://www.hom= ebuiltairplanes.com/forums/threads/exhaust-within-subcowl.30848/page-2#post= -512762] - Matt Boiteau On 2020-01-18 5:29:51 PM, Matt Boiteau wrote: Have started on the exhaust. Made all three primaries 2" double slip joints= (that alone took almost a whole day with welder). The big can (CA -=C2=A0C= entrifugal Accumulator) rolled into a 5" can and we'll secure it to the eng= ine with straps. The inside pipe is 2.75" which has an area of 5.94sq". I'm not sure if ther= e's a magic number, but all the holes I drilled equaled to just under doubl= e the area (11sq"). Most are 3/8, but I did add some 1/2 to get the total a= rea up.=C2=A0Could we get away with drilling less holes? Not sure. I'll be = able to drill out one side end of the CA and pull out the inner tube and ch= ange out. Will=C2=A0experiment=C2=A0later=C2=A0with less holes and monitor = back pressure. Will weld a npt bung on the CA and use the wideband bung to = measure the different. The previous exhaust with just an=C2=A0Aero Turbine 2525XL, measured ~113dB= A. With nothing, was closer to 120dBA. Funny around 2000 prop rpm was loude= r then at 2300 full static.=C2=A0 - Matt Boiteau On 2020-01-07 12:19:23 AM, Matt Boiteau mattboiteau@gmail.com wrote: Okay I'll make all 3 primary tubes (2" diameter) all double slip fit. Weldi= ng=C2=A0batwing=C2=A0tabs (picture below) on to either side on the slips, w= ill hold the muffler to the header but allow expansion. Having troubles finding 2.75" bends in 321, so I might have to just switch = to 3" downpipe that is more common. Vband clamp before downpipe for easier = removal and under the plane to allow adding additional exhaust setups (long= pipe with holes drilled in it, fishmouth tailpipe, etc) I found a company that makes flex bellows in 321. I'm just not sure if I sh= ould have it vertical on the downpipe or close to the muffler horizontal be= fore the first 90degree bend downwards. https://www.aceraceparts.com/products/3-000-flex-bellow-assembly-321-stainl= ess?variant=3D11067135556 [https://www.aceraceparts.com/products/3-000-flex= -bellow-assembly-321-stainless?variant=3D11067135556] Batwing tabs - Matt Boiteau On 2020-01-03 4:22:18 PM, Neil Unger 12348ung@gmail.com wrote: Mat, =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 As usual I have no idea.=C2=A0 I made all 3 sli= p joints and to date no grief in that area.=C2=A0 I am coming around to the= stock manifold in some way.=C2=A0 Yes it is heavy, but appears to muffle t= he noise as well.=C2=A0 Know of 2 installations that use the stock manifold= with a simple muffler after and both claim "acceptable" noise. It appears = that the stock manifold has a big influence on noise??=C2=A0 Would prefer a= DB reading, but if not available it is what it is.=C2=A0 All is compromise= , weight, cost, time, but at the end of the day it has to work.=C2=A0 Still working on the turbo even though the world is on holidays.=C2=A0 All = to save my hearing.=C2=A0 So far the rotary is definitely "unique" as far a= s a turbo is concerned.=C2=A0 The heat generated exceeds all else.=C2=A0 Tw= o things to date -- special exhaust wheel and water cooled bearing body =3D= , all for heat.=C2=A0 Have modified the stock front plate on the renesis to= take an electric water pump.=C2=A0 That is the simple bit. Neil. On 1/4/2020 5:37 AM, Matt Boiteau mattboiteau@gmail.com [mailto:mattboiteau= @gmail.com] wrote: okay I found a good company called SPD Exhaust. They have everything you ne= ed in 321ss. With the engine being an RX8, we have three exhaust ports. Should I weld th= e front and back solid to the muffler, and make the middle one a slip fit f= or expansion? Or vice-vesa? - Matt Boiteau On 2019-12-28 11:03:42 AM, Finn Lassen finn.lassen@verizon.net [mailto:finn= .lassen@verizon.net] [mailto:flyrotary@lancai= ronline.net] wrote: I did something similar with my RV-3 13B decades ago. It split open at the = welds around one of the pipes from the manifold into the the big outer tube= . True, it did use individual manifold base plates, not the connected facto= ry manifold and the big tube was only 0.035. Still, I would recommend slip joints on two of the three pipes, like I adde= d on one of the pipes (cut through and a surrounding bigger pipe -- missing= in picture). Can't remember why I went from the above to individual runners into a perfo= rated pipe under the fuselage. Probably got lured by promise of increased p= ower by tuned lengths and still uncomfortable by the muffler being inside t= he cowling. Finn On 12/28/2019 12:10 AM, Matt Boiteau mattboiteau@gmail.com [mailto:mattboit= eau@gmail.com] wrote: This is what I'm going to try in a few weeks.=C2=A0 "Exhaust valve opens and a pulse of hot gas puffs out through a short pipe,= then=C2=A0tangentially=C2=A0into a cylindrical canister. Being tangential,= the pulse flattens out and travels=C2=A0helically=C2=A0(rather than bounci= ng and reverberating around) along the inside curved wall of the can, spira= ling toward the exit, where it comes out more uniform in flow and so pretty= quiet." Outer pipe =3D 321 ss 0.050 thick. Flat plate bent to a 5" tube Inner pipe =3D 321 ss 0.036 thick. 2.5" diameter (I might use 302ss 0.065 since I already have it) From my understanding, the area of the holes should be double the area of t= he inner pipe.=C2=A0 - Matt Boiteau ------=_NextPart_14627015.030098822393 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

Thanks Charlie for the tip on the spectrum analyzer. I didn't ge= t any before numbers, but it's all low Hz now. That harsh high pitch is gon= e. Db's are still there, but I'd say with just the muffler design, it's com= parable to typical lycoming. I can start to hear the prop noise o= ver the engine noise. I measured back pressure around 3.5psi @ 2200rpm prop= .

I ran out of time to flight test the long pipe under the airplane.= I quickly held it up with my hands and the exhaust pretty much disappeared= with the prop taking over the noise. Before flying, I want to add backpres= sure gauge to that part and drill holes to find a balance between backpress= ure and noise.

SO the "header" muffler shoul= d make quite like any other plane, and the "under belly" pipe will make you= standout in silence.

Since this email type newsletter= is from the dinosaur ages, I'll add pictures and video to&n= bsp;https://www.homebuiltairplanes.com/forums/threads/exhaust-w= ithin-subcowl.30848/page-2#post-512762

- Matt Boiteau

On 2= 020-01-18 5:29:51 PM, Matt Boiteau <mattboiteau@gmail.com> wrote:

=
Centrifugal Accumulator) rolled int= o a 5" can and we'll secure it to the engine with straps.

The inside= pipe is 2.75" which has an area of 5.94sq". I'm not sure if there's a magi= c number, but all the holes I drilled equaled to just under double the area= (11sq"). Most are 3/8, but I did add some 1/2 to get the total area up.&nb= sp;Could we get away with drill= ing less holes? Not sure. I'll be able to drill out one side end of the CA = and pull out the inner tube and change out. Will experimentAero Turbine 2525XL, measured ~113dBA. With nothing, was closer to 120= dBA. Funny around 2000 prop rpm was louder then at 2300 full static. <= br>

- Matt Boiteau

On 2= 020-01-07 12:19:23 AM, Matt Boiteau mattboiteau@gmail.com <flyrotary@lan= caironline.net> wrote:

Okay I'll make all 3 primary tubes (2" dia= meter) all double slip fit. Welding batwing tabs (picture below) on to either side on the slips, will hol= d the muffler to the header but allow expansion.

Having troubles finding 2.75" bends i= n 321, so I might have to just switch to 3" downpipe that is more common. V= band clamp before downpipe for easier removal and under the plane to allow = adding additional exhaust setups (long pipe with holes drilled in it, fishm= outh tailpipe, etc)
=0A = =0A =0A = =0A =0A = =0A
<= br>I found a company that makes flex bellows in 321. I'm just not sure if I= should have it vertical on the downpipe or close to the muffler horizontal= before the first 90degree bend downwards.
https://www.aceraceparts.com/products/3-000-flex-bellow-assembly-3= 21-stainless?variant=3D11067135556


Batwing tabs

- Matt Boite= au
=0A =0A =
=0A On 2020-01-03 4:22:18 PM, Neil= Unger 12348ung@gmail.com <flyrotary@lancaironline.net> wrote:

=0A

Mat,

=0A =

            = ;      As usual I have no idea.  I made all 3= slip=0A joints and to date no grief in that area.  I am coming a= round to=0A the stock manifold in some way.  Yes it is heavy, but= appears to=0A muffle the noise as well.  Know of 2 installations= that use the=0A stock manifold with a simple muffler after and both c= laim=0A "acceptable" noise. It appears that the stock manifold has a b= ig=0A influence on noise??  Would prefer a DB reading, but if not= =0A available it is what it is.  All is compromise, weight, cost,= =0A time, but at the end of the day it has to work. 
=0A <= /p>=0A

Still working on the turbo even though the world is on holiday= s. =0A All to save my hearing.  So far the rotary is definit= ely "unique"=0A as far as a turbo is concerned.  The heat generat= ed exceeds all=0A else.  Two things to date -- special exhaust wh= eel and water=0A cooled bearing body =3D, all for heat.  Have mod= ified the stock=0A front plate on the renesis to take an electric wate= r pump.  That=0A is the simple bit.

=0A

Neil.
=0A =

=0A
On 1/4/2020 5:37 AM, Matt Boiteau= =0A mattboiteau@gmail.com wrote:
=0A
=0A =0A =0A
okay I found a good=0A co= mpany called SPD Exhaust. They have everything you need in=0A 321ss.=
=0A
=0A With the engine being an RX8, we have three e= xhaust ports.=0A Should I weld the front and back solid to the muffl= er, and make=0A the middle one a slip fit for expansion? Or vice-ves= a?
=0A
=0A =0A

=0A =0A
- Matt Boiteau
=0A =0A

On 2019-12-28=0A 11:03:42 AM, Finn Lassen finn.lassen@veri= zon.net=0A <flyrotary@lancaironline.net> wrote= :

=0A
=0A=
I did something similar with my= =0A RV-3 13B decades ago. It split open at the welds around=0A= one of the pipes from the manifold into the the big outer=0A = tube. True, it did use individual manifold base plates,=0A = not the connected factory manifold and the big tube was=0A = only 0.035.
=0A
=0A Still, I would = recommend slip joints on two of the three=0A pipes, like I add= ed on one of the pipes (cut through and a=0A surrounding bigge= r pipe -- missing in picture).
=0A
=0A
=0A
=0A Can't remember wh= y I went from the above to individual=0A runners into a perfor= ated pipe under the fuselage.=0A Probably got lured by promise= of increased power by tuned=0A lengths and still uncomfortabl= e by the muffler being=0A inside the cowling.
=0A =
=0A Finn
=0A
=0A On 1= 2/28/2019 12:10 AM, Matt Boiteau mattboiteau@gmai= l.com wrote:
=0A
=0A
This= =0A is what I'm going to try in a few weeks. =0A =
"Exhaust=0A = valve opens and a pulse of hot gas puffs out through a=0A = short pipe, then tangentially into=0A a cylindrical canister. Being ta= ngential, the pulse=0A flattens out and travels helically<= /i> (rather than bouncing and reverberating=0A = around) along the inside curved wall of the can,=0A sp= iraling toward the exit, where it comes out more=0A unifor= m in flow and so pretty quiet."
=0A

=0A =0A
Outer pipe =3D 321 ss 0.050 thick. Flat plate be= nt to=0A a 5" tube
=0A
Inner pipe= =3D 321 ss 0.036 thick. 2.5" diameter
=0A
(I=0A might us= e 302ss 0.065 since I already have it)
=0A
= =0A

=0A
=0A =
From my understanding, the area of the holes=0A = should be double the area of the inner pipe. 
=0A =

=0A
=0A
- Matt Boiteau
=0A
=0A
= =0A
=0A


=0A

=0A =
=0A
=0A
=0A
=0A=
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