X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) From: "Matt Boiteau mattboiteau@gmail.com" Received: from mail-lj1-f173.google.com ([209.85.208.173] verified) by logan.com (CommuniGate Pro SMTP 6.2.14) with ESMTPS id 812719 for flyrotary@lancaironline.net; Tue, 06 Oct 2020 21:29:39 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.208.173; envelope-from=mattboiteau@gmail.com Received: by mail-lj1-f173.google.com with SMTP id a5so274134ljj.11 for ; Tue, 06 Oct 2020 18:29:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=SjcOAbJX+mSzqOh3xqKM7EJn9Yn+aRC9EG4X8m4CDfQ=; b=YBImZWZxOlog3Vqs7aADqS2+FRomOwfuOBC8qCh3CCfkQxkv4z0Bngt3nIuVSVDlWt W85rI1nfekTOjQKu5kYL7cwYcB+0Zu912p65F8iB47XtvuljE6ZRozc/QnpbzdhA4hVx hKz9h2qwwbG24Y75N9l41iqT5Rd1eRrArUjuEDwVvhSvt4yHjVgOham2s1OnG6d63UAD DM29pONfmHQDQVBXOirPq2H8XsvWpsltF/pw6cD4Xi4RF4aMwy4bAGg4kLOIJaGxJeHA ZxtbRdk1u3NqjMv1kmI/YSI6V9KPiWu0kdG7jmAiVbKm7HajsF9Adu/NVFyAigdrEbH9 YLWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=SjcOAbJX+mSzqOh3xqKM7EJn9Yn+aRC9EG4X8m4CDfQ=; b=NwszOYdlLUFtGUengtMlnQB8uLa6Y9fIOCLkQ/5r0RHVIbLRDy9OiOf50YB2NI+Who Lozu8G32ZlamFEBNw97qxy1pfNj2h3b1obW4WBp8evbVYCykf7O1yJakO9YMqCDzl0rU O8Vx5nnaJ3L2sZQhu+TGmLmYE6e4+v7lVwtc8+nZ35cwkzoivB/dKf5jQ0TttzzUzZXP KAIe+/h6q561THm5NwdOaX7RcjobSfH4UJV6z83AJZMqZRgWHBwUO9sfgz6OvBxZlohH fehkgB0ViSvGQs//IhFqz5lutXAHe9L39Zi7bOHG4dNDjgNms6437y7xG2/HrQJSStnw IArQ== X-Gm-Message-State: AOAM530DNFyZp2e7eVZO7Ux76SjE4DW01YX0wRswvxQQOZJ5nY2VKejw jF4IwN+uv3KaVScTMx1IjxBpz4PbDQ+xfj2F1l1osPi3MNg= X-Google-Smtp-Source: ABdhPJyL5s5nmRUH6S+lz/F5U8lDm3aXaFYHm/BHu3OBQNF/N0FGqGSeF3FEB+wTV2zgupG88q5qVhTQhjpS/PmZV6c= X-Received: by 2002:a2e:911:: with SMTP id 17mr263313ljj.207.1602034161792; Tue, 06 Oct 2020 18:29:21 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 6 Oct 2020 21:29:10 -0400 Message-ID: Subject: Re: [FlyRotary] Re: Mufflers To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000021bd6605b10aa50a" --00000000000021bd6605b10aa50a Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable It's 42miles as the crow flies. I got the normal 25nm increased to 45nm. Now that I'm flying, I'll update the group on my progress. 8 hours in. I think the exhaust is shaking the plane, I was hoping the engine be a smoother plane ride. What do people torque down the Berry mounts to, really tight to compress? - Matt Boiteau On Wed, Sep 30, 2020 at 2:02 PM Finn Lassen finn.lassen@verizon.net < flyrotary@lancaironline.net> wrote: > Hey, I'm just a stone-throw away (9FL5). Surely your test area is include= s > that? > You're welcome to stop by. > > Finn > > On 9/30/2020 8:59 AM, Matt Boiteau mattboiteau@gmail.com wrote: > > Williston (X60 airport) > I'll be there from Oct 3rd to 29th, to fly off my 25hours. So far I have = 6 > hours and had to increase my oil inlet duct size, and redo the exhaust so= I > could hear. We'll see what new bugs will pop up. I'll be posting a lot to > keep people in the loop and help me along the way. > > If people want to visit in person to check out the setup and give me > advice, I'm all ears. > > - Matt Boiteau > > > On Wed, Sep 30, 2020 at 5:38 AM lehanover lehanover@aol.com < > flyrotary@lancaironline.net> wrote: > >> Where in Florida? I live in Florida in the winter. Lynn E. Hanover >> >> In a message dated 9/30/2020 12:48:34 AM Atlantic Standard Time, >> flyrotary@lancaironline.net writes: >> >> >> I've been stuck in Canada far too long. Finally flying to Florida on Sat >> to see my plane and start flying off the hours (trouble free I hope) >> my email is my name (without spaces) at normal gmail dot com. >> >> - Matt Boiteau >> >> On Tue, Sep 29, 2020 at 3:02 PM Bobby J. Hughes bhughes@qnsi.net < >> flyrotary@lancaironline.net> wrote: >> >> Matt, >> >> >> >> Did you make it back to Canada in time for the first snow? I would like >> to discuss your MS install off list when you have time. >> >> >> >> Bobby >> >> >> >> >> >> >> >> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] >> *Sent:* Wednesday, July 08, 2020 7:10 PM >> *To:* Rotary motors in aircraft >> *Subject:* [FlyRotary] Re: Mufflers >> >> >> >> Sadly, by the time the welder and I finished, I only got about 2 hours o= n >> the plane before I had to pack up my winter trip. I was planning to go b= ack >> in March to FL (I live in Canada) to start flying off the 25 hours, but = you >> know how that all went. So I'm just sitting here waiting for the borders= to >> open up and fly my plane! >> >> Early conclusion is it worked pretty darn good. I'd say I'm equivalent t= o >> an IO-360, maybe a tad quieter. Also on ground testing only, I quickly >> mocked up a long tube under the plane with holes drilled in it (with the >> end capped off), and it pretty much got rid of all the engine noise, onl= y >> prop noise. Haven't flown with that yet. One thing I still want to do is >> test the backpressure. Making sure the CAN has enough holes inside. >> >> The best price I found on 321 was from ProFabrication. I went with 2.75" >> 20ga (0.035") on the downpipe & outlet. >> >> https://www.profabrication.com/index.php/products/straight-tubing/321-st= ainless-steel.html >> >> I did use SPD Exhaust for the double slip joints at the primaries and >> downpipe. 2" 16ga (0.06") >> http://www.spdexhaust.com/pdfs/22-23_Tubing.pdf >> >> For the CAN, McMasterCarr 24"x24" 18ga (0.05") rolled into I think a 5 o= r >> 5.5" can. You can go heavier ga, I just guessed. >> https://www.mcmaster.com/1754T51/ >> >> - Matt Boiteau >> >> >> >> >> >> On Wed, Jul 8, 2020 at 2:35 PM Bobby J. Hughes bhughes@qnsi.net < >> flyrotary@lancaironline.net> wrote: >> >> I=E2=80=99m at the exhaust header stage in my S21 FWF build. I=E2=80=99m= considering a >> traditional header, 3-1 merge collector with 1.75=E2=80=9D primaries to= a 2.5=E2=80=9D >> tube. I=E2=80=99m trying to be very weight conscious and looking for pos= sible >> alternatives. The CA manifold can likely be built for nearly the same >> weight as the header design in the picture. I=E2=80=99m a little concern= ed with the >> tangential design. Mark S built and tested one on his 20B. It ran hot an= d >> caused the outer water jacket seals to fail. Mark was not running a >> wideband so he couldn=E2=80=99t see a clear relationship between F/A and= EGT=E2=80=99s. He >> may have be running at or near peak EGT=E2=80=99s. EGT=E2=80=99s for the= renesis can be >> kept to between 1500F -1600F with a little extra or a little less fuel. = I >> will like install the coolant radiator on the belly so adding an externa= l >> muffler would keep it off centerline. >> >> >> >> I have located some reasonable priced Inconel 625 0.040 sheets. If rolle= d >> into a 5-6=E2=80=9D tube, would this thickness be sufficient for a muffl= er shell or >> the CA / tangential manifold tube? >> >> >> >> Matt, >> >> >> >> How is your CA header holding up? >> >> >> >> Thanks, >> >> >> >> Bobby >> >> >> >> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] >> *Sent:* Saturday, January 25, 2020 7:53 PM >> *To:* Rotary motors in aircraft >> *Subject:* [FlyRotary] Re: Mufflers >> >> >> >> 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 tir= ed >> and busy to take 'in progerss' pictures. Was tricky to build, which made >> the hourly welding cost sky high, more then the engine itself. Hopefully >> that means I can save money in the future on hearing aids. >> >> Thanks Charlie for the tip on the spectrum 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 >> comparable to typical lycoming. I can start to hear the prop noise over = 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 >> backpressure gauge to that part and drill holes to find a balance betwee= n >> backpressure and noise. >> >> >> >> SO the "header" muffler should 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 >> https://www.homebuiltairplanes.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 >> - Centrifugal Accumulator) rolled into a 5" can and we'll secure it to t= he >> engine with straps. >> >> The inside pipe is 2.75" which has an area of 5.94sq". I'm not sure if >> there's a magic number, but all the holes I drilled equaled to just unde= r >> double the area (11sq"). Most are 3/8, but I did add some 1/2 to get the >> total area up. Could we get away with drilling less holes? Not sure. I'l= l >> be able to drill out one side end of the CA and pull out the inner tube = and >> change out. Will experiment later with 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 Aero Turbine 2525XL, measured ~113dBA. >> With nothing, was closer to 120dBA. Funny around 2000 prop rpm was loude= r >> then at 2300 full static. >> >> *Error! Filename not specified.* >> >> >> >> - Matt Boiteau >> >> On 2020-01-07 12:19:23 AM, Matt Boiteau mattboiteau@gmail.com < >> flyrotary@lancaironline.net> wrote: >> >> Okay I'll make all 3 primary tubes (2" diameter) all double slip fit. >> Welding batwing tabs (picture below) on to either side on the slips, wil= l >> 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 f= or >> 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 >> should have it vertical on the downpipe or close to the muffler horizont= al >> before the first 90degree bend downwards. >> >> https://www.aceraceparts.com/products/3-000-flex-bellow-assembly-321-sta= inless?variant=3D11067135556 >> >> *Error! Filename not specified.* >> >> >> >> >> >> Batwing tabs >> >> *Error! Filename not specified.* >> >> >> >> - Matt Boiteau >> >> On 2020-01-03 4:22:18 PM, Neil Unger 12348ung@gmail.com < >> flyrotary@lancaironline.net > wrote: >> >> Mat, >> >> As usual I have no idea. I made all 3 slip joints and >> to date no grief in that area. I am coming around to the stock manifold= in >> some way. Yes it is heavy, but appears to muffle the noise as well. Kn= ow >> of 2 installations that use the stock manifold with a simple muffler aft= er >> and both claim "acceptable" noise. It appears that the stock manifold ha= s a >> big influence on noise?? Would prefer a DB reading, but if not availabl= e >> it is what it is. All is compromise, weight, cost, time, but at the end= of >> the day it has to work. >> >> Still working on the turbo even though the world is on holidays. All to >> save my hearing. So far the rotary is definitely "unique" as far as a >> turbo is concerned. The heat generated exceeds all else Two things to >> date -- special exhaust wheel and water cooled bearing body =3D, all for >> heat. Have modified the stock front plate on the renesis to take an >> electric water pump. That is the simple bit. >> >> Neil. >> >> On 1/4/2020 5:37 AM, Matt Boiteau mattboiteau@gmail.com wrote: >> >> okay I found a good company called SPD Exhaust. They have everything you >> need in 321ss. >> >> With the engine being an RX8, we have three exhaust ports. Should I weld >> the front and back solid to the muffler, and make the middle one a slip = fit >> for expansion? Or vice-vesa? >> >> *Error! Filename not specified.* >> >> >> >> - Matt Boiteau >> >> On 2019-12-28 11:03:42 AM, Finn Lassen finn.lassen@verizon.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 out= er >> tube True, it did use individual manifold base plates, not the connected >> factory manifold and the big tube was only 0.035. >> >> Still, I would recommend slip joints on two of the three pipes, like I >> added on one of the pipes (cut through and a surrounding bigger pipe -- >> missing in picture). >> >> *Error! Filename not specified.* >> >> Can't remember why I went from the above to individual runners into a >> perforated pipe under the fuselage. Probably got lured by promise of >> increased power by tuned lengths and still uncomfortable by the muffler >> being inside the cowling. >> >> Finn >> >> On 12/28/2019 12:10 AM, Matt Boiteau mattboiteau@gmail.com wrote: >> >> This is what I'm going to try in a few weeks. >> >> "*Exhaust valve opens and a pulse of hot gas puffs out through a short >> pipe, then **tangentially** into a cylindrical canister. Being >> tangential, the pulse flattens out and travels **helically** (rather >> than bouncing and reverberating around) along the inside curved wall of = the >> can, spiraling 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 the inner pipe. >> >> >> >> - Matt Boiteau >> >> >> >> >> >> *Disclaimer* >> >> The information contained in this communication from the sender is >> confidential. It is intended solely for use by the recipient and others >> authorized to receive it. If you are not the recipient, you are hereby >> notified that any disclosure, copying, distribution or taking action in >> relation of the contents of this information is strictly prohibited and = may >> be unlawful. >> >> This email has been scanned for viruses and malware, and may have been >> automatically archived by *Mimecast Ltd*, an innovator in Software as a >> Service (SaaS) for business. Providing a *safer* and *more useful* place >> for your human generated data. Specializing in; Security, archiving and >> compliance. To find out more Click Here >> . >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> >> > > > Virus-free= . > www.avast.com > > <#m_2355782478043551170_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > --00000000000021bd6605b10aa50a Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
It's 42miles as the crow flies. I got the normal 25nm = increased to 45nm.=C2=A0
Now that I'm flying, I'll update the gr= oup on my progress. 8 hours in. I think the exhaust is shaking the plane, I= was hoping the engine be a smoother plane ride. What do people torque down= the Berry mounts to, really tight to compress?

<= div dir=3D"ltr" class=3D"gmail_signature" data-smartmail=3D"gmail_signature= ">
- Matt Boiteau


On Wed, Sep 30, 2020 at 2:02 PM Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:<= br>
=20 =20 =20
Hey, I'm just a stone-throw away (9FL5). Surely your test area is includes that?
You're welcome to stop by.

Finn

On 9/30/2020 8:59 AM, Matt Boiteau mattboiteau@gmail.com wrote:
=20
Williston (X60 airport)
I'll be there from Oct 3rd to 29th, to fly off my 25hours. So far I have 6 hours and had to increase my oil inlet duct size, and redo the exhaust so I could hear. We'll see what new bugs will pop up. I'll be posting a lot to keep people in the loop and help me along the way.

If people want to visit in person to check out the setup and give me advice, I'm all ears.
=C2=A0
- Matt Boiteau


On Wed, Sep 30, 2020 at 5:38 AM lehanover lehanover@aol.com <flyrotary@lancaironline.net> wrote:
Where in Florida? I live in Florida in the winter.=C2=A0 =C2=A0= Lynn E. Hanover
=C2=A0
In a message dated 9/30/2020 12:48:34 AM Atlantic Standard Time, flyrotary@lancaironline.net writes:
=C2=A0
I've been stuck in Canada far too lo= ng. Finally flying to Florida on Sat to see my plane and start flying off the hours (trouble free I hope)
my email is my name (without spaces) at normal gmail dot com.

- Matt Boiteau

On Tue, Sep 29, 2020 at 3:02 PM Bobby J. Hughes bhughes@qnsi.net <flyrotary@lancaironline.net> wrote:

Matt,

=C2=A0

Did you make it back to Canada in time for the first snow? I would like to discuss your MS install off list when you have time.

=C2=A0

Bobby

=C2=A0

=C2=A0

=C2=A0

From: Rotary motors in aircraft [mailto:flyrotary@la= ncaironline.net]
Sent: Wednesday, July 08, 2020 7:10 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mufflers

=C2=A0

Sadly, by the time the welder and I finished, I only got about 2 hours on the plane before I had to pack up my winter trip. I was planning to go back in March to FL (I live in Canada) to start flying off the 25 hours, but you know how that all went. So I'm just sitting here waitin= g for the borders to open up and fly my plane!

Early conclusion is it worked pretty darn good. I'd say I'm equivalent=C2=A0to = an IO-360, maybe a tad quieter. Also on ground testing only, I quickly mocked up a long tube under the plane with holes drilled in it (with the end capped off), and it pretty much got rid of all the engine noise, only prop noise. Haven't flown wit= h that yet. One thing I still want to do is test the backpressure. Making sure the CAN has enough holes inside.

The best price I found on 321 was from ProFabrication. I went with 2.75" 20ga (0.035") on the downpipe & outlet. https://www.profabrication.com/index.php/product= s/straight-tubing/321-stainless-steel.html

I did use SPD Exhaust for the double slip joints at the primaries and downpipe. 2" 16ga (0.06")
http://www.spdex= haust.com/pdfs/22-23_Tubing.pdf=C2=A0=C2=A0

For the CAN, McMasterCarr 24"x24" 1= 8ga (0.05") rolled into I think a 5 or 5.5&q= uot; can. You can go heavier ga, I just guessed.=C2=A0
https://www.mcmaster.com/1754T= 51/=C2=A0=C2=A0

- Matt Boiteau

=C2=A0

=C2=A0

On Wed, Jul 8, 2020 at 2:35 PM Bobby J. Hughes bhughes@qnsi.net <flyrotary@lancaironline= .net> wrote:

I=E2=80=99m at the exhaust header stage in my S21 FWF build. I=E2=80=99m considerin= g a traditional header, =C2=A03-1 merge collector with 1.75=E2=80=9D primarie= s to a 2.5=E2=80=9D tube. I=E2=80=99m tryi= ng to be very weight conscious and looking for possible alternatives. The CA manifold can likely be built for nearly the same weight as the header design in the picture. I=E2=80= =99m a little concerned with the tangential design. Mark S built and tested one on his 20B. It ran hot and caused the outer water jacket seals to fail. Mark was not running a wideband so he couldn=E2=80= =99t see a clear relationship between F/A and EGT=E2=80=99s.=C2=A0 He may h= ave be running at or near peak EGT=E2=80=99s= . EGT=E2=80=99s for the renesis can be = kept to between 1500F -1600F with a little extra or a little less fuel. I will like install the coolant radiator on the belly so adding an external muffler would keep it off centerline.

=C2=A0

I have located some reasonable priced Inconel 625 0.040 sheets. If rolled into a 5-6=E2=80=9D tube, w= ould this thickness be sufficient for a muffler shell or the CA / tangential manifold tube?

=C2=A0

Matt,

=C2=A0

How is your CA header holding up?<= /p>

=C2=A0

Thanks,

=C2=A0

Bobby

=C2=A0

From: Rotary motors in aircraft [mailto:= flyrotary@lancaironline.net]
Sent: Saturday, January 25, 2020 7:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mufflers

=C2=A0

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 hourly welding cost sky high, more then the engine itself. Hopefully that means I can save money in the future on hearing aids.

Thanks Charlie for the tip on the=C2=A0spectrum analyzer. I didn&= #39;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 th= e muffler design, it's comparable to=C2=A0typical=C2=A0lycoming. I ca= n start to hear the prop noise over 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 backpressure gauge to that part and drill holes to find a balance between backpressure and noise.

=C2=A0

SO the "header" muffler sh= ould make quite like any other plane, and the "under belly&= quot; pipe will make you standout in=C2=A0silence.

=C2=A0

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/forums/thread= s/exhaust-within-subcowl.30848/page-2#post-512762

=C2=A0

- Matt Boiteau

On 2020-01-18 5:29:51 PM, Matt Boiteau <mattboiteau= @gmail.com> 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=A0Centrifugal Accumulato= r) rolled into 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 sur= e if there's a magic number, but all the holes I drilled equaled to just under double the area (11sq"). Most are 3/8, b= ut I did add some 1/2 to get the total area up.=C2=A0Could we get away with drilling less holes? Not sure. I'l= l be able to drill out one side end of the CA and pull out the inner tube and change out. Will=C2=A0experiment=C2=A0lat= er=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 ~113dBA. With nothing, was closer to 120dBA. Funny around 2000 prop rpm was louder then at 2300 full static.=C2= =A0

Error! Filename not specified.

=C2=A0

- Matt Boiteau

<= span style=3D"font-size:10pt;font-family:Arial,sans-serif;color:rgb(170,170= ,170)">On 2020-01-07 12:19:23 AM, Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:

Okay I'll make all 3 primary tubes (2"= ; diameter) all double slip fit. Welding=C2=A0batwing= =C2=A0tabs (picture below) on to either side on the slips, will hold the muffler to the header but allow expansion.

=C2=A0

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 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

Error! Filename not specified.

=C2=A0

=C2=A0

Batwing tabs

Error! Filename not specified.=

=C2=A0

- Matt Boiteau

On 2020-01-03 4:22:18 PM, Neil Unger 12348ung@gmail.com <flyrotary@lancaironline.net> 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 ma= de all 3 slip 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 i= s heavy, but appears to muffle the noise as well.=C2=A0 Know of 2 installations that use the stock manifold with a simple muffler after and both claim "acceptable&qu= ot; 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 f= ar the rotary is definitely "unique" = as far as a turbo is concerned.=C2=A0 Th= e heat generated exceeds all else=C2=A0 Two thin= gs 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.<= /p>

Neil.

On 1/4/2020 5:37 AM, Matt Boiteau mattboiteau@gmail.com wrote:

okay I found a good company called SPD Exhaust. They have everything you need in 321ss.
With the engine being an RX8, we have three exhaust ports. Should I weld the front and back solid to the muffler, and make the middle one a slip fit for expansion? Or vice-vesa?

Error! Filename not specified.

=C2=A0

- Matt Boiteau

On 2019-12-28 11:03:42 AM, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.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 factory manifold and the big tube was only 0.035.

Still, I would recommend slip joints on two of the three pipes, like I added on one of the pipes (cut through and a surrounding bigger pipe -- missing in picture).

Error! Filename not specified.

Can't remembe= r why I went from the above to individual runners into a perforated pipe under the fuselage. Probably got lured by promise of increased power by tuned lengths and still uncomfortable by the muffler being inside the cowling.

Finn

On 12/28/2019 12:10 AM, Matt Boiteau mattboiteau@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=A0= tangentially= =C2=A0into a cylindrical canister. Being tangential, the pulse flattens out and travels=C2=A0= helically=C2=A0(rather than bouncing and reverberating around) along the inside curved wall of the can, spiraling toward the exit, where it comes out more uniform in flow and so pretty quiet.&quo= t;

=C2=A0

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" diamete= r

(I might use 302ss 0.065 since I already have it)

=C2=A0

>From my understanding, the area of the holes should be double the area of the inner pipe.=C2=A0=

=C2=A0

- Matt Boiteau

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