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Post by grizbach on Nov 28, 2012 0:01:49 GMT -8
Well Matt, there are two exhausts. The "planned" one at seat level, and the top one at back level that I added durring construction.
If I turn the seat portion of the bench into a bell, there isn't going to be hardly any heat left for the back. It will just give me another reason to have a larger fuel box. I would defitnatly need more mass. I don't need any more BTU's in this room.
A seat back bell would give the most bang for the buck. A lot more surface area per volume compared to a circular design.
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Post by matthewwalker on Nov 28, 2012 9:40:50 GMT -8
Ah, got it, thank you for the explanation. It's a cool design, I really like the modular aspect. Very versatile.
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Post by grizbach on Dec 15, 2012 8:22:57 GMT -8
I knew this sad day was going to come. I have to make room for the new horizontal rocket.
Here is how this baby has held up through these past 3 yrs.
You can see the top of the tunnel has been a weak point all along. I made a stainless shim(that is pushed out of the way in the photo) to keep the gasses flowing to the riser. It is still intact and about 80% there.
Second concern is the wooden block that was under the burn tube has charring. It should have more than 1/2" of insulation at the ash bin.
Not in the photo is the riser. I was worried about the thin gauge steel burning out. It's rough looking, but by pressing on it, it's still firm.
I'ts going in storage in the garage for now.
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Post by grizbach on Jan 4, 2013 9:00:53 GMT -8
A little update on the riser.
I went to reclaim the perlite from the riser for my new rocket. As I was pouring out the perlite I noticed the riser was pretty flimsy. After a few shakes It fell right off! I'm sure It's been fragile for some time, but without any movement It holds up for a while.
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Post by grizbach on Jan 4, 2013 9:04:49 GMT -8
Also, You can see that perlite does get "cooked", some of it is scorched to a lite tan color. And the granules touching the riser actually fused to the metal.
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Post by satamax on Jan 4, 2013 11:58:34 GMT -8
Show that to the next "clever boy" who thinks metal works in a rocket.  |
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Post by grizbach on Jan 4, 2013 12:42:40 GMT -8
Max, It did last about 2.5 yrs. This was .040" thick I believe.
I don't like the idea of thick metal for the riser. It conducts to much. Hardly any mass to sheet metal, but it does burn out. Balances, balances.
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Post by satamax on Jan 7, 2013 22:31:44 GMT -8
Grizz, well insulated metal is lovely, even thick. It gets red hot, well, i had the feed tube/burn tunel of my first rocket go to bright orange. So, whatever wood you'd throw in was burned real fast and completely. My latest J tube is crap, compared to this one, i have ash buildup, so i have to clean every three or five burn. Sometimes it smokes, and backdrafts!
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