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 812784 for flyrotary@lancaironline.net; Tue, 06 Oct 2020 22:31:18 -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 h20so385000lji.9 for ; Tue, 06 Oct 2020 19:31:19 -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=yK91FK2/ZolFyx1BolqNQckLrenrRzJbBmxCxNPhgEs=; b=eWgaT42giVboJ9vGQAVEghSc7N7cTYNGJEYX3S4PKtmP2DIuYxnNpRvgJg0PMEWumk qm+KTZ6UfKOrp9M/gi3KJ1s/kjrSCsWCu0qnJ4r0f2KyHIY7TbH5gbBOyV8XQUe5u1FK 1BwKz+UernfU6Pl/Wsno9EJcZXeQCg5GCB60cKu8EcfRIcmbNQOS7ZZYIH9oZCZAVxeI bnWiiQLrVlEhZPT0s3TLB2Uo3HM8cT4+TrfVWZD94k1vl9kewYstYfUyiW8TrRp5S9R+ 51Uyy0gfaae/Q3xs/a922aYBSx6z8nmACYuQDAmwrCmjFJY7bsMtqQ0Td0Lq1DsMo3OX hk/Q== 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=yK91FK2/ZolFyx1BolqNQckLrenrRzJbBmxCxNPhgEs=; b=TXjrxNBrgpUtLBipHheQTBnW/x229aGfp5sR8WrgpI3m18mwt5mBA8sYc0qxphPd9U A5KDSdlWK17q6m48XUbUKCpVSCb3SnEfY8DBbyhvX2BSljOTwXlaen9USAAvLo717WhK qn3eN7dj9Xz6q77DO8RTEB9f0c7WPclAVFzrVqDO1UWNVgTLfUDH9F5ROYso91ibK+Om l5ECMJQlceAf15AuFFkLKLc0WtaSr2Ia1w28Y/rXuRE/Vo3oUMwuqvkVl/aRPcMc5+Oi b6+0+8t6Awu0tAN1a1dW4JbX/pCYMZg40LhtQkecP64zrotLozPGwT3a7+78WdRA+75z l5/Q== X-Gm-Message-State: AOAM530OtFjaC8MN+wKp8d8GRDOTF95iLYZwr7Ql+TOMluDDy+sPSTb/ INee9ynqQ97Y7iXhp47m5UV2WHuDhJHfA7vSAI1Pn4fkDf52/A== X-Google-Smtp-Source: ABdhPJzDu8AcCd7fpvG7LJcEQ/a7UiJQWb6mb9yswFx4JtNY2+JXbYmTQWNVK9YCRfbBVTcCe7Q9cQB6ZLQxOf1BqCE= X-Received: by 2002:a2e:721a:: with SMTP id n26mr350007ljc.253.1602037860889; Tue, 06 Oct 2020 19:31:00 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 6 Oct 2020 22:30:50 -0400 Message-ID: Subject: Re: [FlyRotary] Re: Mufflers To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="0000000000009d776f05b10b816d" --0000000000009d776f05b10b816d Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable It's a ground adjustable sensenich prop, that has pins to supposedly line up the blades. The different size pins let me set different pitches. I'll do a full walk around video soon and post it up for everyone to look at and criticize. - Matt Boiteau On Tue, Oct 6, 2020 at 9:37 PM Stephen Izett stephen.izett@gmail.com < flyrotary@lancaironline.net> wrote: > Hi Matt > > Has your Prop been dynamically balanced? > > Steve Izett > > > On 7 Oct 2020, at 9:29 am, Matt Boiteau mattboiteau@gmail.com < > flyrotary@lancaironline.net> wrote: > > > > 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, real= ly > 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 > includes 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 lik= e > 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 > 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 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 > to 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 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-sta= inless-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 > or 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 poss= ible > 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 concerne= d 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. 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 external > muffler would keep it off centerline. > >> > >> > >> I have located some reasonable priced Inconel 625 0.040 sheets. If > rolled into a 5-6=E2=80=9D tube, would this thickness be sufficient for a= muffler > 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 th= e > CAD design to life. Except both days were all nighters, so I was too tire= d > 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 t= he > 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. > >> > >> > >> SO the "header" muffler should make quite like any other plane, and th= e > "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 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 magic 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. Could 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 a= nd > 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 w= as > louder 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, will > 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 fo= r > 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-321-stai= nless?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 a= s > well. Know of 2 installations that use the stock manifold with a simple > muffler after and both claim "acceptable" noise. It appears that the stoc= k > manifold has a big influence on noise?? Would prefer a DB reading, but i= f > not available it is what it is. All is compromise, weight, cost, time, b= ut > 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 < > 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 oute= r > 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, th= e > 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 are= a > 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 m= ay > 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 > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --0000000000009d776f05b10b816d Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
It's a ground adjustable=C2=A0sensenich prop, that has= pins to supposedly=C2=A0line up the blades. The different size pins let me= set different pitches.
I'll do a full walk around video soon and po= st it up for everyone to look at and criticize.


- Matt Boiteau


On Tue, Oct 6, 2020 at 9:37 PM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrot= e:
Hi Matt

Has your Prop been dynamically balanced?

Steve Izett

> On 7 Oct 2020, at 9:29 am, Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.ne= t> wrote:
>
> 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 h= ours 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, r= eally tight to compress?
>
> - Matt Boiteau
>
>
> On Wed, Sep 30, 2020 at 2:02 PM Finn Lassen finn.lassen@verizon.net <flyrotary@lancair= online.net> wrote:
> 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:
>> 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<= /a>> wrote:
>> Where in Florida? I live in Florida in the winter.=C2=A0 =C2=A0Lyn= n E. Hanover
>>=C2=A0
>> In a message dated 9/30/2020 12:48:34 AM Atlantic Standard Time, <= a href=3D"mailto:flyrotary@lancaironline.net" target=3D"_blank">flyrotary@l= ancaironline.net writes:
>>=C2=A0
>> I've been stuck in Canada far too long. Finally flying to Flor= ida on Sat to see my plane and start flying off the hours (trouble free I h= ope)
>> 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@lancaironline.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 h= ours 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 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 to 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 noi= se, only prop noise. Haven't flown with that yet. One thing I still wan= t to do is test the backpressure. Making sure the CAN has enough holes insi= de.
>>
>> The best price I found on 321 was from ProFabrication. I went with= 2.75" 20ga (0.035") on the downpipe & outlet.
>> h= ttps://www.profabrication.com/index.php/products/straight-tubing/321-stainl= ess-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=C2=A0
>>
>> For the CAN, McMasterCarr 24"x24" 18ga (0.05") roll= ed into I think a 5 or 5.5" can. You can go heavier ga, I just guessed= .
>> https://www.mcmaster.com/1754T51/=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.n= et> wrote:
>>
>> I=E2=80=99m at the exhaust header stage in my S21 FWF build. I=E2= =80=99m considering a traditional header,=C2=A0 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 possible alternatives. The CA manifold ca= n likely be built for nearly the same weight as the header design in the pi= cture. I=E2=80=99m a little concerned with the tangential design. Mark S bu= ilt 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 have be ru= nning at or near peak EGT=E2=80=99s. EGT=E2=80=99s for the renesis can be k= ept to between 1500F -1600F with a little extra or a little less fuel. I wi= ll like install the coolant radiator on the belly so adding an external muf= fler 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, would 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?
>>
>>=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 brough= t 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 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 de= sign, 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 @ 2200= rpm 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.
>>
>>=C2=A0
>> SO the "header" muffler should make quite like any other= plane, and the "under belly" pipe will make you standout in sile= nce.
>>
>>=C2=A0
>> 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
>>
>>=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" doub= le slip joints (that alone took almost a whole day with welder). The big ca= n (CA - Centrifugal Accumulator) rolled into a 5" can and we'll se= cure 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 magic 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. Could we get away with drilling les= s 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 experiment later with less ho= les and monitor back pressure. Will weld a npt bung on the CA and use the w= ideband bung to measure the different.
>>
>> The previous exhaust with just an Aero Turbine 2525XL, measured ~1= 13dBA. With nothing, was closer to 120dBA. Funny around 2000 prop rpm was l= ouder then at 2300 full static.
>>
>> Error! Filename not specified.
>>
>>=C2=A0
>> - Matt Boiteau
>>
>> On 2020-01-07 12:19:23 AM, Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironlin= e.net> wrote:
>>
>> Okay I'll make all 3 primary tubes (2" diameter) all doub= le slip fit. Welding batwing tabs (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 t= o just switch to 3" downpipe that is more common. Vband clamp before d= ownpipe for easier removal and under the plane to allow adding additional e= xhaust 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= =A0As usual I have no idea.=C2=A0 I made all 3 slip joints and to date no g= rief in that area.=C2=A0 I am coming around to the stock manifold in some w= ay.=C2=A0 Yes it is heavy, but appears to muffle the noise as well.=C2=A0 K= now of 2 installations that use the stock manifold with a simple muffler af= ter and both claim "acceptable" noise. It appears that the stock = manifold has a big influence on noise??=C2=A0 Would prefer a DB reading, bu= t 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.
>>
>> 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 as a turbo is concerned.=C2=A0 The heat generated excee= ds all else=C2=A0 Two things to date -- special exhaust wheel and water coo= led bearing body =3D, all for heat.=C2=A0 Have modified the stock front pla= te on the renesis to take=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 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0an electric water pump.=C2=A0 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 everythi= ng 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 s= lip 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@lancair= online.net> wrote:
>>
>> I did something similar with my RV-3 13B decades ago. It split ope= n at the welds around one of the pipes from the manifold into the the big o= uter tube True, it did use individual manifold base plates, not the connect= ed factory manifold and the big tube was only 0.035.
>>
>> Still, I would recommend slip joints on two of the three pipes, li= ke 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 o= f increased power by tuned lengths and still uncomfortable by the muffler b= eing 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 tangent= ial, the pulse flattens out and travels helically (rather than bouncing and= reverberating around) along the inside curved wall of the can, spiraling t= oward the exit, where it comes out more uniform in flow and so pretty quiet= ."
>>
>>=C2=A0
>> Outer pipe =3D 321 ss 0.050 thick. Flat plate bent to a 5" tu= be
>>
>> Inner pipe =3D 321 ss 0.036 thick. 2.5" diameter
>>
>> (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
>> - Matt Boiteau
>>
>>=C2=A0
>>=C2=A0
>> Disclaimer
>>
>> The information contained in this communication from the sender is= confidential. It is intended solely for use by the recipient and others au= thorized to receive it. If you are not the recipient, you are hereby notifi= ed that any disclosure, copying, distribution or taking action in relation = of the contents of this information is strictly prohibited and may be unlaw= ful.
>>
>> 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 yo= ur human generated data. Specializing in; Security, archiving and complianc= e. To find out more Click Here.
>>
>> --
>> Homepage:=C2=A0 http://www.flyrotary.com/
>> Archive and UnSub:=C2=A0 =C2=A0ht= tp://mail.lancaironline.net:81/lists/flyrotary/List.html
>>
>
>
>
>=C2=A0 =C2=A0 =C2=A0 =C2=A0Virus-free. www.avast.com


--
Homepage:=C2=A0 http://www.flyrotary.com/
Archive and UnSub:=C2=A0 =C2=A0http://mail= .lancaironline.net:81/lists/flyrotary/List.html
--0000000000009d776f05b10b816d--