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01-18-2019, 10:48 AM
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Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 829
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Heat Muff Orentation
I was just sitting at the table playing with the new heat muff that arrived today from Vans. I bout a second to put in series. I never thought too much about the orientation of the excentric mounts. I have always placed the inlet/outlet ports on the high side. I'm starting to think that they should be on the low side. - Does anyone have data to support the delta T one way or another?
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01-18-2019, 10:56 AM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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The flow velocity is high enough that I don't think port orientation matters.
What does matter is pipe temp and time exposure to the hot pipe(s).
The best performance comes from having the muff(s) on the hottest portion of the pipes possible.
There is also performance gain from ganging two muffs together in series.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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01-18-2019, 11:08 AM
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Join Date: Oct 2005
Location: Estes Park, CO
Posts: 3,947
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Heat muffs in series
Quote:
Originally Posted by rvbuilder2002
The flow velocity is high enough that I don't think port orientation matters.
What does matter is pipe temp and time exposure to the hot pipe(s).
The best performance comes from having the muff(s) on the hottest portion of the pipes possible.
There is also performance gain from ganging two muffs together in series.
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I would love to see photos of two heat muffs in series. Anyone?
__________________
Larry Larson
Estes Park, CO
http://wirejockrv7a.blogspot.com
wirejock at yahoo dot com
Donated 12/03/2019, plus a little extra.
RV-7A #73391, N511RV reserved (2,000+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
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01-18-2019, 11:32 AM
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Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 829
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I'll have one by the end of the weekend, but I always forget how to post photos on there. I'm doing one per pipe. I have not figured out the scat runs yet.
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01-18-2019, 12:43 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by wirejock
I would love to see photos of two heat muffs in series. Anyone?
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It is standard on the RV-14(A)
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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01-18-2019, 01:22 PM
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Join Date: May 2009
Location: Reedley, California
Posts: 85
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[IMG]  [IMG]  [/IMG]
Not in series, but one muff off cyl 1, and the other off cyl 4. The airflow is in series, combined they work almost too well.
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01-18-2019, 03:27 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by dwrichey
[IMG]
Not in series, but one muff off cyl 1, and the other off cyl 4. The airflow is in series, combined they work almost too well.
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Seriesed airflow is what I meant. It doesn't matter if it crosses over to the other side of the engine. Just so all the flow passes through two heat muffs.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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01-18-2019, 03:59 PM
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Join Date: Nov 2005
Location: Asheville, NC
Posts: 2,692
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Quote:
Originally Posted by wirejock
I would love to see photos of two heat muffs in series. Anyone?
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Hi Larry,
I have an M1B in my 7A. Heat was anemic with single muff on #1 ex pipe. I had Rick Robbins make a short muff of my design to go on #4. Additionally, since I was blocking the majority of my oil cooler anyway, I picked up the input air from the back of the cooler. So, the flow is: cooler, #4 muff, #1 muff then cabin.
All this did make an improvement however like Scott said, pipe temp (egt) makes a big difference. I can't run low RPM over square LOP in the coldest winter days and expect the heater to keep me warm. Push some flame into the exhaust with RPM or ROP and the heater will keep up when it's COLD.
Sorry for no pics. Expercraft.....
RIGHT. Made it home to real 'puter. Here is a link to my older VAF post on same subject with images until they disappear due to Expercraft. Look quick.
http://www.vansairforce.com/communit...78&postcount=6
__________________
Bill Pendergrass
ME/AE '82
RV-7A: Flying since April 15, 2012. 850 hrs
YIO-360-M1B, mags, CS, GRT EX and WS H1s & A/P, Navworx
Unpainted, polished....kinda'... Eyeballin' vinyl really hard.
Yeah. The boss got a Silhouette Cameo 4 Xmas 2019.
Last edited by rzbill : 01-18-2019 at 06:27 PM.
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01-18-2019, 04:57 PM
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Join Date: May 2011
Location: Ontario, Canada
Posts: 263
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Sorry no pics but I run 2 muffs in series on my O360 powered 7 with the Vans supplied Vetterman exhaust. The muffs are both installed reverse flow (discharge out closest to the prop) and hooked up in series (discharge of one flows into the inlet on the other) to a single heat box. I now get much more heat in the cabin than with the single muff. Barely warm with the single muff at -6C last winter. This winter at -10C (coldest so far) and very comfortable under full overcast. FWIW.
Al
Last edited by RV7 To Go : 01-18-2019 at 04:59 PM.
Reason: configuration
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01-18-2019, 05:15 PM
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Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,558
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Agree with Scott, two in series is the way to go, at least for the RV8. I did that on my first RV8 with a Vetterman crossover exhaust and I had plenty of heat in the winter. On my new RV8 I have an AWI four into one exhaust and just one heat muff - and its not enough, so I?ll be trying to figure out how to add a second muff in series with the other one, although there are some space constraints in my installation. With two heat muffs in series, it shouldn?t be a problem.
__________________
SH
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO
JAN2020
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