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heat muff report

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Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Tue Oct 24, 2006 11:20 am Post subject: heat muff report

I tested my heat muff output today, after installing aluminum "pot 

scrubbers" (hereinafter to be called pads) in one muff, and stainless 

steel pads in the other. Just to refresh  MY memory, I have a Jabiru 

2200 engine, air-cooled, and these muffs (not muffLERS) are clamped 

around the exhaust pipes. The EGT is 1370-1430 (or so) degrees F. just 

prior to where the exhaust pipe enters the heat muff. The heat muffs 

are 3" in diameter, and about 6" long. There are some baffles inside 

them. It was suggested on this group that I insert some metal pads into 

the muffs to slow down the passage of air, thus allowing the air to 

become warmer before it entered the cockpit/cabin. Here is what I found 

today:



At 3700' MSL, (2800'AGL),  I flew at 89-103 IAS,  2780 rpm,  31 degrees 

F. OAT, 1415 F. EGT,  240 F. CHT, and got 140-150 F. for the muff with 

the SS pads inside, and about 104-110 F. for the muff containing the 

aluminum pads. The thermocouples were placed in the SCAT hose,  about 

2" behind the respective muffs. This temperature drops considerably, I 

would think, after leaving the muff, as the air travels about 2 feet 

before entering the cabin. Next time the cowl is off, I'll change the 

aluminum pads for SS, and seal up some air leaks around the cabin 

doors, root ribs, head rack, etc.



In retrospect, if I could have made the heat muffs a lot larger, I 

would have, but space is at a premium for building a muff on a Jabiru 

exhaust system. Now to corral the heat, and stuff the cracks...

Lynn

Kitfox IV Speedster...Jabiru 2200

do not archive

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Tue Oct 24, 2006 11:36 am Post subject: heat muff report

Lynn,   I love you report .   NO BS  and factual .



I will keep my SS pads in my muff   



And Deke............  about your question  the cockpit ?  Well maybe now 

that Lynn has a warmer cockpit due to his heatmuff  his plane should be 

called..................................................................... 

the MuffPit .....or  a kit FOX with a Muff PIT    ........  



Dave

---

_________________
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algate(at)attglobal.net
Guest

Posted: Tue Oct 24, 2006 12:40 pm Post subject: heat muff report

Dave I'm glad you love Lynn................



Regards



Gary Algate

 	  Quote: 	
		  >>>>>>>>>>>>>>>>>>>

Lynn,   I love you report .   NO BS  and factual .
	


<<<<<<<<<<<<<<<<<<<<



I will keep my SS pads in my muff   



And Deke............  about your question  the cockpit ?  Well maybe now 

that Lynn has a warmer cockpit due to his heatmuff  his plane should be 

called..................................................................... 

the MuffPit .....or  a kit FOX with a Muff PIT    ........  



Dave

---

Fox5flyer
Guest

Posted: Tue Oct 24, 2006 12:43 pm Post subject: heat muff report

Excellent report Lynn!  What sort of meter were you using with the

thermocouples?  Why don't you just elaborate specifically what you used to

get these readings.  I'm interested.

Deke



do not archive



---

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Tue Oct 24, 2006 1:12 pm Post subject: heat muff report

Easy, big fellah, EASY.....



I guess I should also report that while I now know how to make the  

muffs put out more heat (thanks for the tips, group) that it ain't  

nearly ENOUGH  heat to keep the cabin warm....and this was at 31  

degrees F.   I'm gonna really need to seal air leaks to be able to  

operate at the temps that Michigan hands out in the winter, let alone  

go to, say, Norway, or what was that phrase I read last week...those  

"treacherous Southern California winters?"



Lynn

do not archive

On Tuesday, October 24, 2006, at 04:44  PM, Algate wrote:



[quote] 



 Dave I'm glad you love Lynn................



 Regards



 Gary Algate

>>>>>>>>>>>>>>>>>>>>

 Lynn,   I love you report .   NO BS  and factual .

 <<<<<<<<<<<<<<<<<<<<



 I will keep my SS pads in my muff   



 And Deke............  about your question  the cockpit ?  Well maybe  

 now

 that Lynn has a warmer cockpit due to his heatmuff  his plane should be

 called................................................................. 

 ....

 the MuffPit .....or  a kit FOX with a Muff PIT    ........  



 Dave

 ---

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Tue Oct 24, 2006 1:25 pm Post subject: heat muff report

LOL  that was a typo   -- hell--   love you -- I harldy know you   

?     should have read   > I  LOVE R YOUR REPORT  <



Anyhow ---  how much inlet size do you have compared to your  scat  piping ? 

I would guess that you need larger in than out to start and get more 

aircoming through  and more SS  pads to slow it again down.   Keep 

experimenting.....  I know I did and I  kept adding  SS  and it gets very 

warm in cabin now with alot of airleaks.

Dave

---

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Tue Oct 24, 2006 2:12 pm Post subject: heat muff report

Hi Deke-

The meter I'm using is a Craftsman AutoRanging Digital MultiMeter, 

model 82175...about an $80 meter. It came with a type K 

(chromel-alumel) temperature probe. It really would be better if it was 

a type J (iron-constantan) probe, as they are more suited to the below 

500F or so, temperature range. Type K's are better suited to the above 

500 F range...we used to use the K's on exhaust system measurements at 

Chrysler. The meter reads out in F or C and "indicates the proper 

decimal point and value." I don't know if the unit would read right if 

used with a type J probe, however.



The thermocouples are kinda short...about 36"...so I had to run them 

under the cowl and up over my instrument panel cover, then plug them 

into the meter body, one at a time. I wish I had longer t'couples, and 

could plug them into a "real" meter and then simply turn the dial to 

whatever "station" I wanted to read. But I have to unplug one lead, 

then plug in the other...one-handed, while flying...makes for an 

interesting "track" on the GPS. : )



I can attest to the "pretty good accuracy" of the unit, as I used it to 

calibrate my iron for shrinking my fabric, and also when inserted into 

my mouth, it read about 92 F....give me a break, guys, I'm 70 years 

old! ....a guy cools down after all those years....



Lynn



On Tuesday, October 24, 2006, at 04:43  PM, Fox5flyer wrote:



 	  Quote: 	
		   



 Excellent report Lynn!  What sort of meter were you using with the

 thermocouples?  Why don't you just elaborate specifically what you 

 used to

 get these readings.  I'm interested.

 Deke



 do not archive

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Tue Oct 24, 2006 2:37 pm Post subject: heat muff report

The right side muff with the SS pads has a  2" dia. straight-in collar  

right behind the prop, and about 6" out from the periphery of the  

spinner...about the same location circumferentially as the  

engine-cooling air intakes. The left side muff has a NACA duct on the  

side of the cowl that feeds a 2" SCAT hose.



The one thing that I keep pondering is this:

  The air bends around after entering the NACA duct, comes forward  

through the SCAT hose, then goes into the muff, then travels rearward  

through the muff, into a cabin heat box and into the cabin (or  

overboard). On the right side, the air travels pretty straight into the  

rear of the muff, goes forward through the muff, then out into the SCAT  

hose where it travels rearward through a selective "T", then into the  

cabin (or overboard). I could add another straight-in collar for the  

left-side muff, and do away with the NACA duct, but I wanted to prove  

the system before I started punching more holes into the cowl.

I set it up this way (zig-zagging) to slow the air and pick up more  

heat, I thought. Any ideas on the circuitry?



Lynn

On Tuesday, October 24, 2006, at 05:24  PM, Dave wrote:



[quote] 



 LOL  that was a typo   -- hell--   love you -- I harldy know you   

 ?     should have read   > I  LOVE R YOUR REPORT  <



 Anyhow ---  how much inlet size do you have compared to your  scat   

 piping ? I would guess that you need larger in than out to start and  

 get more aircoming through  and more SS  pads to slow it again down.    

 Keep experimenting.....  I know I did and I  kept adding  SS  and it  

 gets very warm in cabin now with alot of airleaks.

 Dave

 ---

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Oct 24, 2006 4:21 pm Post subject: heat muff report

Good old fashioned empirical experimentation... Works every time.



Thanks for the report Lynn



Noel



Do not archive



[quote] --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Fox5flyer
Guest

Posted: Tue Oct 24, 2006 5:06 pm Post subject: heat muff report

Thanks Lynn.  I was wondering how you did that.

Deke

do not archive

 	  Quote: 	

 Hi Deke-

 The meter I'm using is a Craftsman AutoRanging Digital MultiMeter, 

 model 82175...about an $80 meter. It came with a type K 

 (chromel-alumel) temperature probe. It really would be better if it was 

 a type J (iron-constantan) probe, as they are more suited to the below 

 500F or so, temperature range. Type K's are better suited to the above 

 500 F range...we used to use the K's on exhaust system measurements at 

 Chrysler. The meter reads out in F or C and "indicates the proper 

 decimal point and value." I don't know if the unit would read right if 

 used with a type J probe, however.

 The thermocouples are kinda short...about 36"...so I had to run them 

 under the cowl and up over my instrument panel cover, then plug them 

 into the meter body, one at a time. I wish I had longer t'couples, and 

 could plug them into a "real" meter and then simply turn the dial to 

 whatever "station" I wanted to read. But I have to unplug one lead, 

 then plug in the other...one-handed, while flying...makes for an 

 interesting "track" on the GPS. : )

 I can attest to the "pretty good accuracy" of the unit, as I used it to 

 calibrate my iron for shrinking my fabric, and also when inserted into 

 my mouth, it read about 92 F....give me a break, guys, I'm 70 years 

 old! ....a guy cools down after all those years....

 Lynn

 On Tuesday, October 24, 2006, at 04:43  PM, Fox5flyer wrote:

 > 

 >

 > Excellent report Lynn!  What sort of meter were you using with the

 > thermocouples?  Why don't you just elaborate specifically what you 

 > used to

 > get these readings.  I'm interested.

 > Deke

 >

 > do not archive

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Oct 24, 2006 5:24 pm Post subject: heat muff report

Get a good winter flight suit and fly with the door open!



Noel



Do not archive



[quote] --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Wed Oct 25, 2006 2:18 pm Post subject: heat muff report

A followup after stuffing some foam in the cavities around the front 

spar, and using some foam weatherstrip at the front of the doors, and 

laying a strip of tape on the gap under the wings at the butt rib:



I didn't check temperatures, because I already did them and hadn't 

changed anything on the muffs from yesterday. But I did take the plane 

up to 9300 feet MSL, and with an OAT of 19 degrees F at that altitude, 

it was comfortable inside. The EGT was ~1415F. What was NOT comfortable 

was when I started the descent and the EGT got down to 1139 F, and my 

cozy cabin got chilly.



Next I'm going to build something to close the open space between the 

rear of the baggage sack and where the turtle deck attaches....it feels 

cold back there. And I've still got some cold air coming in...maybe 

between the cowl and the windshield.



Lynn

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

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