Bronze Wool for heat muff

[KayS]

Darin, your modification looks great! could you in some way "quantify" the improvement? some or a lot more heat?

[AlexPeterson]

Almost 100% of the RVs I look at have what is called, in the heat exchanger world, concurrent flow set up for the heat muffs. This is where the exhaust gas and the heated air go through the muff go the same direction. This is sub-optimal. Counter-current is going to result in hotter air. Put the supply air into the aft end of your muff, with heated air coming out the forward end of it. I've not measured how much difference this would be, but it is likely quite a bit.

Avoid putting the heater on a crossover pipe - there is noticeably less heat from a heater on a pipe fed by one cylinder as compared to two, even though it is closer to the cylinder on the crossover.

Use caution with the bronze wool - it might only be a plated mild steel. I've found many "SS" wools to also be just a plated mild steel, which will rust fairly quickly in this environment. (Edit: it appears that the OP's bronze wool is indeed just plated - the label says "rust resistant").

[bill.hutchison]

Originally Posted by Darin Watson

Posted this earlier… works great!

https://vansairforce.net/community/s...67&postcount=6

That's really cool.

I'm rigging the 12V heated shirt from my motorcycle gear, too.

[WingsOnWheels]

I have the vetterman mufflers on my 6A (O-360). I only have 1 plumbed with a heat shroud. I get so much heat, I rarely crack the heat more than 2-3 clicks on the detent push/pull cable. That is even when cruising at 13K in winter under an overcast layer. That said, I would like to add a liner or carpet under the seat, the seat pan still gets cold even with the pushrod boots.

[rmarshall234]

Originally Posted by AlexPeterson

Put the supply air into the aft end of your muff, with heated air coming out the forward end of it. I've not measured how much difference this would be, but it is likely quite a bit.


Use caution with the bronze wool - it might only be a plated mild steel. I've found many "SS" wools to also be just a plated mild steel, which will rust fairly quickly in this environment. (Edit: it appears that the OP's bronze wool is indeed just plated - the label says "rust resistant").

Excellent. Thanks Alex. I will absolutely go with the Counter-current ducting design - that makes perfect sense to me. And, where's my magnet to check this "Bronze Wool". Geezz...whatever happened to truth in advertising. Ha!

As for an optimal design...it looks like Darin has the best approach with his aluminum fingers that stick up into the airflow. Brilliant!

[Freemasm]

Originally Posted by Darin Watson

Posted this earlier… works great!

https://vansairforce.net/community/s...67&postcount=6

Very nice.

Key to maintaining its effectiveness would be maintaining solid contact with the pipe. Did you do anything to tension it? Stainless strip?

[rmarshall234]

I tried to pick up a single strand of my Bronze Wool with a big ol' magnet and it just sat there on the table so it does appear that I have the real deal. I completed the installation this am and will report back if there is anything notable.
Thanks guys.

[pa38112]

I have 2 heat muffs in series, both stuffed with steel wool - it is OK, but never gets truly warm. The canopy is sealed, the rear baffle is sealed, no boots on the control rods.

[Darin Watson]

Originally Posted by Freemasm

Very nice.

Key to maintaining its effectiveness would be maintaining solid contact with the pipe. Did you do anything to tension it? Stainless strip?

With the bent up ends for the #8 threaded screw, and the fact both the pipe and material for “finned clamp” are both SS, there does not seem to be any loosening due to thermal cycles.

[Darin Watson]

Originally Posted by KayS

Darin, your modification looks great! could you in some way "quantify" the improvement? some or a lot more heat?

Somewhat challenged to quantify, but I would say it was chilly at -10C with “normal chothing” prior to shirtsleeves now and at -20C you want to start to zip up your jacket. My wife and I were up at 17,500 on a cold day over Montana once and the OAT was reading -53C on the way to Mexico, and it did get uncomfortably cold…I think it was -30ish on the ground that day.