Pyrohawk Posted August 8, 2006 Posted August 8, 2006 Yeah if ya want bigger payloads use a core burner.... A 1 lb core burner can easily lift 150g. I have launched a 170g shell and could probably have gone even bigger....
joe609 Posted August 17, 2006 Posted August 17, 2006 Has anyone tried putting like an augmenter or whatever they are on the bottom of your rockets it should increase power shouldnt it?
Wiedras Posted August 25, 2006 Posted August 25, 2006 does BP in the rocket engine is rammed dampened or dry?
Pretty green flame Posted August 25, 2006 Posted August 25, 2006 does BP in the rocket engine is rammed dampened or dry? It is rammed dry. Damp ramming may cause cracks in the fuel grain leading to CATO's.
itwasntme Posted August 25, 2006 Posted August 25, 2006 I've been making bp engines for a while now. I have a 75% success rate. I might try a dummy payload now. It's a 3/8 +/- homemade rolled tube about 3 inches long. I use commercial goex 3FG bp and a 1/8th inch nozzle. I'm trying to get some air float charcoal and some sulfur to make my own, but I'm broke. What weight of a payload would you reccomend me trying? 5gram? 10 gram? thanks PS: is there anyway for me to slow down my powder without using a mill or charcoal?PPS: should I get airfloat or 80 mesh? I don't care much about tails just consitency(sp?) and charcoal stars.
Von Bass` Posted August 25, 2006 Posted August 25, 2006 I've been making bp engines for a while now. I have a 75% success rate. I might try a dummy payload now. It's a 3/8 +/- homemade rolled tube about 3 inches long. I use commercial goex 3FG bp and a 1/8th inch nozzle. I'm trying to get some air float charcoal and some sulfur to make my own, but I'm broke. What weight of a payload would you reccomend me trying? 5gram? 10 gram? thanks PS: is there anyway for me to slow down my powder without using a mill or charcoal?PPS: should I get airfloat or 80 mesh? I don't care much about tails just consitency(sp?) and charcoal stars. I would start small, and work up. I never tried a dummy payload, I just made something simalar to the pic: http://i8.tinypic.com/25jca6d.gif The idea is, it tests the delay comp, just to make sure that the header isnt going to ignite prematurely. The layer of darker grey is the delay (I use 50:50 Bp:C) Ontop of the delay, I place 0.1 - 0.2g of corned BP, when this ignite, it pops the top off, telling you at what point the rocket header would have gone off in mid air. When you know you have a decent delay, just build bigger and better headers for your rocket. I beleive a 1lb rocket can lift 150g, but Im not sure as to your sizing. Have fun
itwasntme Posted August 25, 2006 Posted August 25, 2006 thanks. Isn't corned bp 15:3:2? Thats what I think goex 3Fg is. So what could I use? grass seed coated bp? Can I make that with commercial bp?
TheSidewinder Posted August 26, 2006 Posted August 26, 2006 Commercial "g" powders won't work well (or at all) for coating seeds or rice hulls, as the powder grains are glazed with graphite. You would have to regrind it into meal, would still have the graphite as an impurity, and I *think* that graphite would make coating hard, if not impossible. Commercial "a" powders would also need to be milled down, but at least it would be pure and would result in excellent meal. It's a hell of a lot simpler to make your own Meal Powder, though. Scrape some cash together and get the basic ingredients. You will need some sort of mill. Hmmm... I re-read your post: for a header to "annouce" the burnthru of the delay, wrap a half-teaspoon of commercial 3Fg in a small square of tissue paper or kleenex, tamp it on top of the delay with the excess tissue pointing up (so there's only *one* layer of paper between 3Fg and delay comp), then press a slightly oversize disk above it. Add a nose cone if you feel like it. I'm also surprised you are getting ANY rockets to work using a commercial "g" powder. I've tried a number of times with no success. They all blew up. As soon as I started making my own propellants, they worked fine. And I thought both Goex and Elephant powders were standard 75:15:10, but I'm not certain. M
hst45 Posted August 26, 2006 Posted August 26, 2006 Make/buy a ball mill, and you'll save a ton of money in the long run, and have a much better chance of success. If, in the mean time, you want to try to make a delay comp and/or slow down your BP, you might try a drop or two of mineral oil. I remember reading about this somewhere as a way to slow down meal powder, so it might have that effect on commercial BP. I can't attest to this personally, so try only a small sample so you don't waste too much, and my apologies in advance in case I'm wrong.
moonshot Posted September 8, 2006 Posted September 8, 2006 Here are some pics of my standard 3 oz. rocket. I call it 3 oz. because size wise it falls between a 2 oz and 4 oz motor size. specs are...Hand rolled tube 3/8" ID 4" long 3/16" wall.Motor rammed on homemade tooling using milled kitty litter for nozzle.Propellent is 71 KNO3 24 grapevine charcoal 5 sulfur.I use Dhurams water putty for the plug. It doesn't crumble when drilled.The heading is the cone cup as per my posted tutorial. this one is pasted with paper bag.Payload is about 2 oz of coal firedust stars and homemade BP break. I add some 3f commercial to give it some kick. Break is random but pretty.The stick is cedar 1/4" square 32" long. I cut these myself. they are very light and straight. overall length about 36". Hope to get some video of it soon to post. http://i107.photobucket.com/albums/m314/di...07/S3011388.jpghttp://i107.photobucket.com/albums/m314/di...07/S3011377.jpghttp://i107.photobucket.com/albums/m314/di...07/S3011383.jpg
rocket Posted October 28, 2006 Posted October 28, 2006 Do you guy think that a 28” stick would be long enough to stabilize a 4 oz rocket made with pro tooling (pyrotooling.com)? Thanks
hst45 Posted October 28, 2006 Posted October 28, 2006 That sounds about right, but it depends on the size and density of the stick. A thin bamboo garden stake would probably be fine, but a piece of hardwood ripped down to 1/4" x 1/2" would probably be too heavy. I would suggest starting out using the thinnest stick material that supports the rocket motor without excessive flexing. Then trim down the end 1/2" at a time until the assembled rocket balances just the slightest bit tail heavy.
rocket Posted October 28, 2006 Posted October 28, 2006 The sticks on the rocket are pine so there not to heavy, the diameter however is not very exact it like a wavy sea i cut them with a ban saw. The only pro now is I have to make some more motors as the ones I just made had to gooder BP in them so they CATOed. Anyways thank for the help
hst45 Posted October 28, 2006 Posted October 28, 2006 Yeah, that gooder BP will do that, thats fur shur. Try adding about 10% baking soda to meal to slow it down. Either that or try about two wraps of that fiberglass-stranded packing tape to reinforce the motor tube. Clamp a fence on the bandsaw table and you can rip the sticks straight.
rocket Posted October 29, 2006 Posted October 29, 2006 I’ve made up some 60/30/10, which should be slow enough. I’ve use a 50/50 mix of willow/newspaper charcoal with it as straight willow may be to fast and it’s a bit of a waste of the willow.
Andyscoolsn Posted October 29, 2006 Posted October 29, 2006 does BP in the rocket engine is rammed dampened or dry?It is rammed dry. Damp ramming may cause cracks in the fuel grain leading to CATO's.So THATS why ive had so little succes with rockets! wow i feel like an idiot. So you just ram it completely dry? put in your nozzle then core it? some where i read that it had to be dampened to ram it. How exactly does it crack the fuel grain? Im interested in learning how that works.
rocket Posted October 29, 2006 Posted October 29, 2006 As the water evaporates from the grain it shrinks which causes it to crack, its like when a lakebed dries out it cracks.
Andyscoolsn Posted October 29, 2006 Posted October 29, 2006 Thanks for informing me, I'm interested to see how dry ramming it will be compared to ramming damp bp with the performance of the rocket.
psymon Posted October 30, 2006 Posted October 30, 2006 I have some tools from pyrotooling.com for 3/4 inch rockets. I tried 60/30/10 mix but this results in a cato. Then I tried 55/35/10 and this was so slow the rocket barely got out of the the launch tube. I didnt realise a small difference in ratios would creat such a massive difference in performance. Tomorrow I will try 57/33/10 and hopefully i will get a decent launch.
itwasntme Posted October 30, 2006 Posted October 30, 2006 I have some tools from pyrotooling.com for 3/4 inch rockets. I tried 60/30/10 mix but this results in a cato. Then I tried 55/35/10 and this was so slow the rocket barely got out of the the launch tube. I didnt realise a small difference in ratios would creat such a massive difference in performance. Tomorrow I will try 57/33/10 and hopefully i will get a decent launch. Maybe try a shorter core? I don't know what else it could be.
Mumbles Posted October 30, 2006 Posted October 30, 2006 6/3/1 is a pretty standard ratio. I would try several of the same formula before trying to change the formula. The problem could just be a crack in the grain, or air pocket or a defect in the tube. Heres a trick we use in the lab for FTIR. For FTIR spectroscopy, you mix your product with KBr and press thin pellets of it. Before pressing/ramming your increment try pusing the rammer down and spinning it around a few times to evenly distribute everything. Sometimes I wonder if this is some people's problems. An uneven distribution of product could result in soft pockets, which could also cause a CATO.
cplmac Posted October 31, 2006 Posted October 31, 2006 I do that on every increment I press mumbles, and the only CATO I have had so far was from a split casing. Of course I have only made about 30 rockets, so that number WILL be going up. I press the hell out of my mix too, and personally I think that goes a long way towards keeping the CATO at bay. I'm going to start compiling all my pressures, increment sizes and tube diameters because I think the rocket pressures that are standard could be raised. Of course these are the ramblings of a new rocketman who has had really good luck thus far. When I press motors with metal in them I bring the pressures back down.
moonshot Posted October 31, 2006 Posted October 31, 2006 Thanks for informing me, I'm interested to see how dry ramming it will be compared to ramming damp bp with the performance of the rocket. I ram my rocket motors dry and they work great. I would suggest graining your propellent with some dextrin before ramming if it's as fine as airfloat. This will keep the stuff from flying all over the place when you put the rammer into the tube. I've rammed motors with meal BP but it gets real messy.
Pretty green flame Posted October 31, 2006 Posted October 31, 2006 Thanks for informing me, I'm interested to see how dry ramming it will be compared to ramming damp bp with the performance of the rocket.I ram my rocket motors dry and they work great. I would suggest graining your propellent with some dextrin before ramming if it's as fine as airfloat. This will keep the stuff from flying all over the place when you put the rammer into the tube. I've rammed motors with meal BP but it gets real messy. No, don't use dextrin, it will make the granules too hard so they may not compact properly (possibility of CATO's). But i agree with everything else moonshot said. Do granulate your comp as it will pour better and keep dust down.
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