pocket rocket help

[marco]

hey Donkey,
looking for some advice on a larger pocket rocket for garage heating application. The barrel is made from 22" stove pipe, 2' tall; the feed tube is 6", with a 5" exhaust, just short of 5' tall. The exhaust is double wall b type venting (1/2" air gap), inside of a 10" diameter pipe, which is filled with vermiculite insulation. it runs...but i expected a lot more. I get small amounts of smoke out the feed tube, and often, the flame creeps up the wood in the feed tube. Certainly seems like a draft issue to me, no? any thoughts on improvement? i thought it would border on a flame thrower with that exhaust...

[Donkey]

Sounds like a constriction.
Pocket rocket you say??
Usually constrictions in pocket rockets are at the bottom of the feed tube. Try raising it a little.
Actually.. Get it started and move the feed tube up/down. There should be a "sweet spot".

[marco]

Good call, I actually made it adjustable. It did help, but I think it is still under performing. Such a simple device, how hard can it be?! My smaller scale ones crank...is it possible that the chamber is too large?

[Donkey]

What size is the pipe that you're using?
Oh, right.. 6 inch with 5 inch exhaust.
Try stepping up to eight inch pipe..

It could be that the chamber is too large. Now that you mention it, There's probably an optimum volume ratio for any given pipe size.
Hmm.. Honestly, I haven't spent a whole lotta time with pocket rockets..
You'll have to play with it and let us know.. ??

[marco]

will do. thanks for the help; I've learned a lot from your site, and appreciate your time.

[marco]

Donkey,
spot on with the constriction diagnosis. took it apart, saw a large piece of paper stuck it the exhaust..aha! so much draft it sucked apiece of cardboard up! I thought. But closer inspection revealed it was...molten metal!? Turns out the inner pipe in bvent is aluminum. Melted the tube almost shut. cut it out, loaded the chamber and lit it up. Awesome! sweet draft, tons of heat, flames shooting out the exhaust. Until it melted again. will rebuild it this weekend with better materials.

[canyon]

I love it! Getting so hot you need better materials is a sure sign of a hot fire! Isn't pyromainia a good dis position?

[shane]

I love all my pocket rockets. I wish everything was as easy as these little furnaces. The 25 gallon barrel with 7 inch feed and 5 inch stack in my sauna works quite well. We can get the temp in there from -25C to +30C in about 15-20 minutes.g:\rocket forum\IMG_0837.jpg[/img]g:\rocket forum\IMG_4740.jpg[/img]g:\rocket forum\IMG_4751.jpg[/img]
(Hmmm, I can't figure out how to include pictures)