From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Mufflers
Date: Wed, 7 Oct 2020 12:52:57 +0800
References: <list-812788@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-812788@logan.com>
Message-Id: <44879C1D-F5C8-4370-A9CF-375B0F2AD340@gmail.com>

Hi Matt

Do you have access to a prop balancing tool. Think car wheel/tire =
balancing.
I used a friends and it makes such a huge difference to vibration.

The balancing tool I use is basically a laser and pickup pointing at a =
reflective tape that you place on the back of the spinner.
This gets the rpm and angle measurement.=20
Then it has an accelerometer to measure the vibration.
It spits out a vibration figure (from memory calibrated in =
inches/second) and provides a rotational position to add weight.
Ah. Watch the video. https://www.youtube.com/watch?v=3D-2p9m_UhSAU

Hope I=E2=80=99m not telling you something you already know.

Steve Izett


> On 7 Oct 2020, at 10:30 am, Matt Boiteau mattboiteau@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> 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.
>=20
>=20
> - Matt Boiteau
>=20
>=20
> On Tue, Oct 6, 2020 at 9:37 PM Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
> Hi Matt
>=20
> Has your Prop been dynamically balanced?
>=20
> Steve Izett
>=20
> > On 7 Oct 2020, at 9:29 am, Matt Boiteau mattboiteau@gmail.com =
<flyrotary@lancaironline.net> wrote:
> >=20
> > It's 42miles as the crow flies. I got the normal 25nm increased to =
45nm.=20
> > 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?
> >=20
> > - Matt Boiteau
> >=20
> >=20
> > 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.
> >=20
> > Finn
> >=20
> > 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.
> >>=20
> >> If people want to visit in person to check out the setup and give =
me advice, I'm all ears.
> >> =20
> >> - Matt Boiteau
> >>=20
> >>=20
> >> 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
> >> =20
> >> In a message dated 9/30/2020 12:48:34 AM Atlantic Standard Time, =
flyrotary@lancaironline.net writes:
> >> =20
> >> 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.
> >>=20
> >> - Matt Boiteau
> >>=20
> >> On Tue, Sep 29, 2020 at 3:02 PM Bobby J. Hughes bhughes@qnsi.net =
<flyrotary@lancaironline.net> wrote:
> >> Matt,
> >>=20
> >> =20
> >> 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.
> >>=20
> >> =20
> >> Bobby
> >>=20
> >> =20
> >> =20
> >> =20
> >> From: Rotary motors in aircraft =
[mailto:flyrotary@lancaironline.net]=20
> >> Sent: Wednesday, July 08, 2020 7:10 PM
> >> To: Rotary motors in aircraft
> >> Subject: [FlyRotary] Re: Mufflers
> >>=20
> >> =20
> >> 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!
> >>=20
> >> 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.
> >>=20
> >> 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-stai=
nless-steel.html
> >>=20
> >> 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 =20
> >>=20
> >> 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.=20
> >> https://www.mcmaster.com/1754T51/ =20
> >>=20
> >>=20
> >> - Matt Boiteau
> >>=20
> >> =20
> >> =20
> >> On Wed, Jul 8, 2020 at 2:35 PM Bobby J. Hughes bhughes@qnsi.net =
<flyrotary@lancaironline.net> wrote:
> >>=20
> >> I=E2=80=99m at the exhaust header stage in my S21 FWF build. I=E2=80=99=
m 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 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=99=
t 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.
> >>=20
> >> =20
> >> 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?
> >>=20
> >> =20
> >> Matt,
> >>=20
> >> =20
> >> How is your CA header holding up?
> >>=20
> >> =20
> >> Thanks,
> >>=20
> >> =20
> >> Bobby
> >>=20
> >> =20
> >> From: Rotary motors in aircraft =
[mailto:flyrotary@lancaironline.net]=20
> >> Sent: Saturday, January 25, 2020 7:53 PM
> >> To: Rotary motors in aircraft
> >> Subject: [FlyRotary] Re: Mufflers
> >>=20
> >> =20
> >> 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.
> >>=20
> >> 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.
> >>=20
> >> 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.
> >>=20
> >> =20
> >> SO the "header" muffler should make quite like any other plane, and =
the "under belly" pipe will make you standout in silence.
> >>=20
> >> =20
> >> 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.3=
0848/page-2#post-512762
> >>=20
> >> =20
> >> - Matt Boiteau
> >>=20
> >> On 2020-01-18 5:29:51 PM, Matt Boiteau <mattboiteau@gmail.com> =
wrote:
> >>=20
> >> 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.
> >>=20
> >> 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 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.
> >>=20
> >> The previous exhaust with just an Aero Turbine 2525XL, measured =
~113dBA. With nothing, was closer to 120dBA. Funny around 2000 prop rpm =
was louder then at 2300 full static.=20
> >>=20
> >> Error! Filename not specified.
> >>=20
> >> =20
> >> - Matt Boiteau
> >>=20
> >> On 2020-01-07 12:19:23 AM, Matt Boiteau mattboiteau@gmail.com =
<flyrotary@lancaironline.net> wrote:
> >>=20
> >> 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.
> >>=20
> >> =20
> >> 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)
> >>=20
> >>=20
> >> 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-stain=
less?variant=3D11067135556
> >>=20
> >> Error! Filename not specified.
> >>=20
> >> =20
> >> =20
> >> Batwing tabs
> >>=20
> >> Error! Filename not specified.
> >>=20
> >> =20
> >> - Matt Boiteau
> >>=20
> >> On 2020-01-03 4:22:18 PM, Neil Unger 12348ung@gmail.com =
<flyrotary@lancaironline.net> wrote:
> >>=20
> >> Mat,
> >>=20
> >>                   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.  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??  Would prefer a =
DB reading, but if not available it is what it is.  All is compromise, =
weight, cost, time, but at the end of the day it has to work.=20
> >>=20
> >> 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.
> >>=20
> >> Neil.
> >>=20
> >> On 1/4/2020 5:37 AM, Matt Boiteau mattboiteau@gmail.com wrote:
> >>=20
> >> okay I found a good company called SPD Exhaust. They have =
everything you need in 321ss.
> >>=20
> >> 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?
> >>=20
> >> Error! Filename not specified.
> >>=20
> >> =20
> >> - Matt Boiteau
> >>=20
> >> On 2019-12-28 11:03:42 AM, Finn Lassen finn.lassen@verizon.net =
<flyrotary@lancaironline.net> wrote:
> >>=20
> >> 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.
> >>=20
> >> 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).
> >>=20
> >> Error! Filename not specified.
> >>=20
> >> 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.
> >>=20
> >> Finn
> >>=20
> >> On 12/28/2019 12:10 AM, Matt Boiteau mattboiteau@gmail.com wrote:
> >>=20
> >> This is what I'm going to try in a few weeks.=20
> >>=20
> >> "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."
> >>=20
> >> =20
> >> Outer pipe =3D 321 ss 0.050 thick. Flat plate bent to a 5" tube
> >>=20
> >> Inner pipe =3D 321 ss 0.036 thick. 2.5" diameter
> >>=20
> >> (I might use 302ss 0.065 since I already have it)
> >>=20
> >> =20
> >> >=46rom my understanding, the area of the holes should be double =
the area of the inner pipe.=20
> >>=20
> >> =20
> >> - Matt Boiteau
> >>=20
> >> =20
> >> =20
> >> Disclaimer
> >>=20
> >> 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.
> >>=20
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