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Post by Donkey on Oct 12, 2014 11:38:55 GMT -8
Here is a jpeg of the .skp file for those who don't want to install Sketchup just to see an image... Oops, I get a message "This forum has exceeded its attachment limit. There is no more space to store attachments" or similar wording. Can anything be done about this? Yep.. I'll need to go through all existing attached files and delete the dead-wood.. I've been WAY too busy to even want to start that project.. There is a button to simply flush ALL attachment files, but I don't really want to go there. Best way to go, use a 3rd party file host that allows linking out. |
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Post by fastthebest on Mar 12, 2018 14:39:13 GMT -8
Hi, here is the picture of my 'mock up' and i have some questions. i.imgur.com/lrf2t5V.jpgIs the covered part of the burning tunnel too short ? Only 4,5" ! I stick up to 8" system numbers and feed tube and burnin chamber are 8,8" x 5,71" and i am also a little bit concerned is it maybe too rectangular ? Burnin g tunnel length is 22"...Thanks in advance... |
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gjh42
Junior Member
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Post by gjh42 on Mar 13, 2018 8:56:47 GMT -8
That does look very rectangular. I can't say whether it is too much so for good operation.
The roof of your burn tunnel is effectively 5.8" counting the thickness of the riser wall, which is still short, but may be long enough. What I find concerning is the very short feed tube - at only 9" high, it will not hold reasonable length sticks. You will want at least another course of bricks to get the height to 13.5".
Using centerline dimensions and 4.5" as "1" for the feed tube length, you have something like 1:3:6 or more (I can't tell how tall your riser is from the picture). Another course of brick for the feed would make it (9" = "1") 1:1.5:3+, which is a reasonable proportion.
The other common method of proportioning, which is a bit more stringent, is to measure along the outside edges of the elements. This would give you (9" = "1") 1:2.5:3.5+ as is, or (13.5" = "1") 1:2:2.7+ with another course of brick on the feed. So by that system, you would be on the short side for the riser height. If you have eight courses in the riser instead of the seven courses visible, you would get a good 1:2:3 ratio.
The main issue with the burn tunnel roof being too short would be that you can't fit your barrel over the riser after insulating it while keeping airspace between riser and barrel, and crowding the feed opening with the barrel side.
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Post by fastthebest on Mar 16, 2018 14:53:01 GMT -8
Thanks for the reply...Here is newer picture (it is veeeery bad and dark but i think you will understand it)...My heat riser has 9 bricks...And about the barrel placing, i am planing to heat one side more so i'll move it to the side oposite of burn tunnel roof...I will add another course of bricks to the feed tube for sure...Do you think that is ok ? Will it work for sure ? Some more advices ? Thanks a lot anyway... Here is newer but darker picture: ibb.co/bE7y0H |
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lst
New Member
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Post by lst on Jul 9, 2018 1:51:48 GMT -8
Hi, I have seen J tube type rockets around that do not fall exactly in the types described in this thread. If I had to draw it, it would be a bit like this: ▌ ▌ ▌ ▌ ▌ ▌ Wood feed ▌ ▌ Here no air after ▌ ▌ fire starts ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▂▂▂▂▂▌ ▌▂▂▂▂▂▂▂▌ ▌ Air in here ▌Here secondary air ▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▌ Sorry for the sloppy artwork  What would be the correct proportions of such a system? Thanks |
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Post by satamax on Jul 9, 2018 2:15:35 GMT -8
Well. What you are describing, is not a rocket. Really, not something working well.
Secondary air is cooling the spot which should be hotest. Primary air doesn't go through the wood, so there is not pre mixing of wood gases. If wood feed is left open, it smokes back. There is also too much primary air. No turbulence created at the first j tube elbow. I think it's better to stick to proved designs.
The only thing alike, which has a little interest, F Styles magazine rocket. Ans no testo has sniffed that obe, as far as i know of.
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Post by Vortex on Jul 9, 2018 5:10:03 GMT -8
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lst
New Member
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Post by lst on Jul 9, 2018 23:51:53 GMT -8
Well. What you are describing, is not a rocket. Really, not something working well. Secondary air is cooling the spot which should be hotest. Primary air doesn't go through the wood, so there is not pre mixing of wood gases. If wood feed is left open, it smokes back. There is also too much primary air. No turbulence created at the first j tube elbow. I think it's better to stick to proved designs. The only thing alike, which has a little interest, F Styles magazine rocket. Ans no testo has sniffed that obe, as far as i know of. Thanks Satamax for the clear response. I thought there would be some tests as I have seen those types of rockets around the web. Also it looks like there are very different designs between masonry and metal. My problem is that I would be better served with one of those designs common in metal, but I need to do it with mortar and bricks. Given the fundamental issue of non tested design cannot be addressed, in any case, pardon my crude drawing, I was thinking some of your concerns would be addressed by the following ideas: ▌ ▌ ▌ ▌ ▌ ▌ Wood feed ▌ ▌ Here no air after ▌ ▌ fire starts ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▌ ▂▂▂▂▂▌ ▌▂▂▂▂▂▂▂▌ ▌ Air in with damper X X ▌Here secondary air release Secondary air in here XX ▌ ▂▂▂▂▂▂XX▂▂▂▂▂▂▂▂▌ 1) The wood would be burned inside the burn channel, where the XXs are and the air should go through burning wood; 2) The primary air intake has a damper that reduces the dimension of the air intake, increasing turbulence; 3) The secondary air is released in the elbow between the burn channel and the riser, but the intake is at the front getting hot air instead of cold air in the burn area; Hope this is not too far-fetched as design. Thanks again |
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lst
New Member
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Post by lst on Jul 9, 2018 23:53:30 GMT -8
Hello Vortex, thanks for your suggestion. I don't seem to understand that video but I will go on the channel to study what they are doing. Thanks and best |
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Post by Vortex on Jul 10, 2018 0:24:06 GMT -8
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lst
New Member
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Post by lst on Jul 10, 2018 23:26:40 GMT -8
Thanks a lot I can see that he has done something very similar to what I want to achieve. Now it's only a matter of choosing the dimensions. Going back to the standard J-tube dimensions, this should be more or less like creating a 0-2-4 Rocket stove (given no air comes from the wood loading chamber). From the looks of it there should be no real problems making it work fine. Thanks for the suggestion. |
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Post by satamax on Jul 11, 2018 8:08:08 GMT -8
Careful with primary air, and secondary air, p channel implementation.
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lst
New Member
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Post by lst on Jul 11, 2018 23:38:47 GMT -8
Careful with primary air, and secondary air, p channel implementation. Thanks Satamax. I will study the rieser-less idea from Peter van den Berg and will try not to screw it up too much. If I ever come to a reasonable design I will let the forum know. Thanks again. |
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