missile_man Posted March 15, 2007 Posted March 15, 2007 Iv just made my first proper 1lb rocket with tools from pyrotooling.com and proper 3/4" X 7.5" tubes for the job. I rammed a nozzle out of powdered cat litter, the propelland was 65:35 KNO3:sugar, slghtly melted and powdered again and the top plug was cat litter again. I hammered everything into the tube with a cloth over my dowels (prevent damage) and tapped the finished rocket to check for loose propellant. unfortunately the nozzle and top blew out completely with the top half of the tube ripped apart can anyone spot where iv gone wrong?
cplmac Posted March 15, 2007 Posted March 15, 2007 You can't ram a 1lb rocket with a hammer. You just are not likely to even approach the necessary pressure. You need 6500PSI as the recommended pressure for loading a BP rocket, more or less. This requires a press. What is probably happening is that you are not compacting the grain enough and small cracks or fissures in the grain are taking fire and increasing the pressure to much.
Frozentech Posted March 15, 2007 Posted March 15, 2007 Iv just made my first proper 1lb rocket with tools from pyrotooling.com and proper 3/4" X 7.5" tubes for the job. I rammed a nozzle out of powdered cat litter, the propelland was 65:35 KNO3:sugar, slghtly melted and powdered again and the top plug was cat litter again. I hammered everything into the tube with a cloth over my dowels (prevent damage) and tapped the finished rocket to check for loose propellant. unfortunately the nozzle and top blew out completely with the top half of the tube ripped apart can anyone spot where iv gone wrong? Not sure, I am not experienced with sugar rockets, however, when you ram a BP rocket, it helps to use a recoiless hammer. Perhaps some of the candy rocket folks have better advice ?
ewest Posted March 15, 2007 Posted March 15, 2007 What the heck is a recoiless hammer? I ram 1lb BP rockets by hand. I used Meal-D (gets everywhere I should granulate it) with a deadblow hammer. Sugar rockets just seem like they're too fussy, people always seem to have some problem or another with them.
itwasntme Posted March 15, 2007 Posted March 15, 2007 slghtly melted and powdered again and the topHow finely did you powder it? If its fairly coarse, then the flame front went through the gaps in the fuel, and thats what caused the cato. Just use powdered sugar, and powdered kno3. No need to melt. Just use a core.
missile_man Posted March 15, 2007 Author Posted March 15, 2007 cheers for the feedback. a ram would be ideal but i would only make a rocket now and then. im sure iv seen a mallet being used on greg boyds website. my propallent varied in grain size, just went through a regular kitchen seive so maybe the burn rate was too fast. so yea, i think next time i wont bother melting and see how it goes.
Mumbles Posted March 16, 2007 Posted March 16, 2007 Some of the problem might be that you're trying to make sugar rockets with BP tooling. Sugar rockets generally need an end burning design. The core burn possibly caused your cato. You don't say if the cato happened imediatly upon ignition, or part way through the burn. Right away is caused by too high of initial pressure, possibly from the core, and possibly from a grain void. Later in the burn is from a grain void.
Aquarius Posted March 16, 2007 Posted March 16, 2007 James Yawn has some good starter points on his homepage: www.jamesyawn.com. KNSU-rockets are a bit "complicated" to make at first, but well worth the effort once you get the hang of it. I suggest using a cast, cored design at first, finding the right length of the grain by starting small. KNSU is surprisingly powerful.. For the more expereienced, try Richard Nakka's site.
itwasntme Posted March 16, 2007 Posted March 16, 2007 Some of the problem might be that you're trying to make sugar rockets with BP tooling. Sugar rockets generally need an end burning design. The core burn possibly caused your cato. You don't say if the cato happened imediatly upon ignition, or part way through the burn. Right away is caused by too high of initial pressure, possibly from the core, and possibly from a grain void. Later in the burn is from a grain void. WHAT? I think you have it the other way around, almost all of the documents on sugar rockets I have read states to use a core. Usually BP burns to fast, if milled and an endburning design is used.
deadman Posted March 17, 2007 Posted March 17, 2007 He didn't say it couldn't have a core, but that they are usually used in Rcandy. It is hard to have a cored rocket work well. And Rcandy usually uses a much smaller core than that designed for blackpowder. Black powder and Kn/Su mix have very different characteristics. So it would not be wise to expect tooling for one to work with the other. I would definitley start with endburners/semicored if your going to be starting out at the 1 pound level.
al93535 Posted March 18, 2007 Posted March 18, 2007 Ewest: You use meal-D to make 1 lb cored BP rockets?
ewest Posted March 19, 2007 Posted March 19, 2007 Yep. It's messy as all get out, but I do. It's a 60:20:10 mix though, not a traditional 75:15:10 BP But I use it straight from the ball mill, I don't bother to granulate it.
ActionTekJackson Posted March 27, 2007 Posted March 27, 2007 Alright, first, I've made several 1lb Kn/Su rockets using my standard BP tooling, in fact, that used to be the only thing I could get to fly as my BP just CATO'd. In response to the original post, simply finely powder your KNO3 and buy some powdered sugar, mill them if you have no other means of intimately mixing them rather well. Then ram these, I have never had success with my press (I was excited and way over zealous to get it done and realized I'd made it too small), but I've got rammed 1lb rockets down. Kn/Su mix will work with BP tooling, there's just no need to melt the mix unless you are going to make fuel grains and treat it like a composite motor (which I would not suggest for a 1lb motor, way too much work for that small size).
CrazyIsraeli Posted May 29, 2007 Posted May 29, 2007 You can't ram a 1lb rocket with a hammer. You just are not likely to even approach the necessary pressure. You need 6500PSI as the recommended pressure for loading a BP rocket, more or less. This requires a press. What is probably happening is that you are not compacting the grain enough and small cracks or fissures in the grain are taking fire and increasing the pressure to much. Okay but is it possiable to put just a spoon inside and then hammer itand then add another spoon of powder and hammer it and so forth?It will take a lot of time, but is it possiable? or still not enough (sledgehammer maybe?)
cplmac Posted May 29, 2007 Posted May 29, 2007 It's possible to do, it's just not likely to be very consistant. Just make sure you use the same size increment, and I highly recommend against doing this with whistle which needs even more pressure than BP.
CrazyIsraeli Posted May 29, 2007 Posted May 29, 2007 with overlooking the parctiaclities, Is it possiable?
optimus Posted May 29, 2007 Posted May 29, 2007 I highly recommend against doing this with whistle which needs even more pressure than BP. and is also prone to explode from being rammed. Don't ram whistle!
CrazyIsraeli Posted May 29, 2007 Posted May 29, 2007 That changes about everything...I know from past experiance that flash powder is sensitive...My moronic friend just dropped a small glass container which had about 1g flash mix left in it... good thing it was old and not so pure...
MisterSteve Posted May 29, 2007 Posted May 29, 2007 Maybe you should use real bentonite instead of cat litter. Not all cat litter works and maybe what you're using isn't good enough
invisibleworld Posted August 27, 2007 Posted August 27, 2007 A recoiles or dead blow hammer is one that is full of lead shot. Works perfect for ramming. After doing a few, you notice the difference in your elbow for sure.
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