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exhaust and muff GAP


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Hi Cozybuilders and flyers,


My cabin heating in my COZY (O-235) has always been largely inadequate. When I lately removed my Exhausts (4 pipe) I noticed quite a large gap between the exhaust pipe and the Muff used for cabin heating and Carbu heating...


It's hard to describe, that's why I included a picture of the installation with this email. On the picture, the shroud around pipes 2 and 4 is already removed.


Should this gap be closed off with RTV ...?


Can anybody please comment on this...?



Thanks and best regards,


Cozyflyer Bjorn:)


Flying was my first love and it will be my last one!

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As near as I can tell, everyone has always had trouble with heat muffs on Lycs. My best information on how to make them work better is as follows:


1. Make your muff surround the exhaust pipe to the extent possible/practical

2. Fill the muff with stainless steel wool (pot scrubbers from the grocery store). They will provide a much greater heated surface area exposed to the air flow and will heat the air much better/hotter.

3. Ventilate the cabin. There is not enough air pressure in the engine compartment to force the air into the cabin if there is no readily available exit. One way to vent the cabin is to open the outboard lower wing bolt access cover and perhaps cover it with a "vent) (opening aft) to draw air out, and then ensure there is a free path for air to flow from the cabin through the spar and out.

4. Be prepared to put some sort of fan in the hot air system (say, in the hell hole or somewhere like that) to increase flow of hot air.

5. If all esle fails, ask me how to build a benign (low pressure) cabin heater using engine oil as the medium.


Just a theory .... Jim S.

...Destiny's Plaything...

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I'd say RTV would probably ignite:eek:


Is the gap where the air enters the muff, or is there an opening below?


Is it directly connected to a ram-air or does it just get air from the engine compartment?


I'm actually astoundingly ignorant about this, and used to be terrorfied of the heater in my brother's Kombi...

Mark Spedding - Spodman
Darraweit Guim - Australia
Cozy IV #1331 -  Chapter 09

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Thanks Jim...,


The tip with the stainless steel wool makes sense! I'll try it!Not that I expect wonders, but we'll see.


Spodman..., it only gets air from the engine, no extra RAM air.



It's still not clear to me if the gap needs to be there or not... I'll post one more picture in a different post,named "picture COZY Heater Muff", just to make clear how the finished installation, looks like.



regards and safe flying,


Cozylover Bjorn :confused:

Flying was my first love and it will be my last one!

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