taiwanluthiers Posted July 4, 2012 Posted July 4, 2012 I made a bottle rocket and tested it empty (I want to make sure it flies before I load it with stars or salute)... here is the video, glad I did not load it with anything! IMG_0640.MOV
taiwanluthiers Posted July 4, 2012 Author Posted July 4, 2012 Two more... one CATO'ed, one flew better than the first time (I increased its thrust by lengthening the core, the first one wasn't enough, the second one was too much, and the third one could use a little more...) I used the slow burning meal powder that was made from BBQ charcoal, I will use willow charcoal next time but will have to start the experiment over again because willow burns hotter. Here is all 3 videos on youtube... in case this one does not work.
Potassiumchlorate Posted July 4, 2012 Posted July 4, 2012 Haha, cute little rockets. The first one didn't fly very well, though.
Mortartube Posted July 4, 2012 Posted July 4, 2012 I think the second one may have popped the choke out. Possibly more down to your clay ramming abilities than any other fault.
spitfire Posted July 4, 2012 Posted July 4, 2012 The quality of your BP doesn't matter that much for a first-timer. Ofcourse it needs a little more than just fizzling and sputtering BP. Finely ground BP from bbq charcoal should do the trick. For a rocket without a payload all that is important is the tube (strong enough) a deep core and good firmly rammed clay choke. If you don't have any rocket tooling, you can slowly drill the core. Be aware of heat building up, so clean the drill bit many times and wear proper protection! (eyes and hand) Keep trying and stay safe!
taiwanluthiers Posted July 4, 2012 Author Posted July 4, 2012 I think the second one may have popped the choke out. Possibly more down to your clay ramming abilities than any other fault. No, the choke did not blow out. It was still in place, but the end plug did blow out.
Potassiumchlorate Posted July 4, 2012 Posted July 4, 2012 How hard do you ram and with how many blows? I'm by no means a rocket expert, but I have made some ½", 3/4" and 1" rockets, coreburners and stingers, and a few fountains, and I usually ram each increment with 10-15 blows.
taiwanluthiers Posted July 5, 2012 Author Posted July 5, 2012 I didn't count, probably about 5 blows each increment. I hit pretty hard each blow though. How hard am I supposed to ram the powder?
Seymour Posted July 5, 2012 Posted July 5, 2012 As hard as you can while reliably not damaging the tube. For good tubes this is very hard, though with weaker tubes, there is a fine line that can only become instinct by destroying a few tubes... A 1/2" rocket, I hammer about as hard as I would if I was hammering in a nail. For a 1" rocket, it's more like as hard as I can sustain it without getting too tired. I only give each increment 1-5 hits. What are you using for the nossle and end plug? Without coarse rocks of clay, grog or some other material to bite in to the tube, I've had problems like these.
taiwanluthiers Posted July 5, 2012 Author Posted July 5, 2012 (edited) I am using ground up kitty litter, it works well. I have made another one out of willow charcoal, end burner, and SUCCESS!!! (video will come up in a new thread) I guess anything wider than 1" would require a hydraulic press? I wonder how they make that giant black powder rocket in Thailand without that going CATO? That rocket has to be at least 4" in diameter! Edited July 5, 2012 by taiwanluthiers
Potassiumchlorate Posted July 5, 2012 Posted July 5, 2012 No, as long as it is BP rockets, it should be possible to ram very large ones. A very heavy mallet will give harder impact=good compression of the powder.
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