by mannytheseacow » Tue Nov 25, 2014 2:07 pm
Hi Hpmer,
Yes, increasing the feed height helped me a lot. I think there was a couple of things that changed about that same time that really helped the situation out too.
First, yes, I would recommend building the feed up. If your fuel is consistently cut to about the same length, try building the feed up to near that height. I know it throws the ratios off but I don't think the ratio is really that important, especially with a short running flue path. This is just my opinion, but I thing constricting the air flow around the fuel gets the air drawing faster down around the fuel, achieving what you are after.
A couple other comments, though...
These outdoor cookers are slightly more challenging in my opinion. I have my old maple syrup/barrel burner, which is kind of a joke, and then these natural cores that I've been playing with using your core mixture (ash/soil) for this community development project I've been working on. These are more of an Approvecho style open top/recessed cooker but with a J-shaped core. I've been building the feed up on these, too, which seems to help. For outdoor stoves, though, you really don't have that high temperature differential like you would with an indoor rocket (warmer air inside/cooler air outside) that really helps them draw without even having a fire going.
Then you also have to consider that you don't burn outdoor stoves nearly as often, so they take much longer to dry out, and you are usually firing it cold.
Building up the feed on my indoor J really helped, but around that same time the temps outsided started dropping considerably, and I think the core and mass were also starting to really dry out and function properly. So I believe all these factors came into play. Though, like I said, building the feed up to the level of your fuel height helps, in my limited experience.
"Knowledge is power. Arm yourself."