nick2354 Posted February 9, 2008 Posted February 9, 2008 Hello, I am not to sure if there is a thread about this already but I would like to know how to attach fins (or any other stabilization device) to my black powder rockets. All of my rockets so far have gone straight up to about 100 metres and then begin flying horizontal, I guess this is because once most of the fuel has burnt it loses its stabilization (I believe this is mentioned some where in this thread). I have seen some method of no fins only a metal rod with a straw around it which is attached to the rocket. Has anyone tried this and had some results, failures succeses, I would to love hear about it because I live in the suburbs and dont like the idea a of my a large piece of dal (wood) falling on someones house.
WarezWally Posted February 9, 2008 Posted February 9, 2008 Nobody does it as its to much work when: 1. Chances are you will never see the rocket again (by design or not) so you have to do everything again.2. Its hard to do and doesn't work well with a shell on the end.3. Sticks are damn easy to perfect. Sounds like you need a longer stick.
Arthur Posted February 9, 2008 Posted February 9, 2008 Stick stabilised rockets do fly into the wind as the thrust falls off. Stingers are spin stabilesed rockets without a flying stick, but they take more making! Fin stabilisation is possibly only used for amateur rocketry purposes where there will be a coloured drogue 'chute to ease recovery of the whole thing.
nick2354 Posted February 9, 2008 Posted February 9, 2008 Damm, I hope someone was going to say its easy and it works every time, ohh well.... I guess I will keep making them with a stick. I hope to attach a header to one of them very soon.
oskarchem Posted February 9, 2008 Posted February 9, 2008 Hehe, well I'm pretty ppy, I mean my BP rockets "Finally" take off, and well only core burners, becaus my end burners don't make enough thrust. But they seem to go a bit "missile" Ok so guys, here is a vid of my BP rocket: sorry about the quality, but I didn't have a normal camera under my hand, so well, I did it with my phone. Oh, and I will be making a header rocket soon aswell.BP Rocket SO here are the 2 other rockets I made this eavning: BP Core rocket, it went compleatly missileBP Core Missile BP Core CATO w/ 1 3/4" headerBp Core CATO
nath0r Posted February 14, 2008 Posted February 14, 2008 You've got some nice rockets there, shame about the CATO but keep at it, as the well known saying goes, if at first you dont succeed, try again. Good luck with your next attempt
moonshot Posted February 15, 2008 Posted February 15, 2008 Your rocket motors work great! I think the instability problem comes from using a stick that is too short. In my experience a stick that is longer and lighter will make your rocket fly straighter than one that is shorter and heavier. The CATO was great! keep working on them!
oskarchem Posted February 15, 2008 Posted February 15, 2008 Hey, thanks gyus, well the tick was long enough, I balanced it on my finger, and it was very light. But I think one of the major problems is the fact tht I think my BP is too slow burning. And the CATO well I drilled the core way too far.
InRainbows Posted February 15, 2008 Posted February 15, 2008 oskar, why would your rocket would CATO if you drilled too far, maybe it was something with your nozzle? I'm betting that your nozzle had too small a vent hole or that it wasn't thick enough. What were the dimensions of the tube, and did you find the rocket's tube?
FrankRizzo Posted February 15, 2008 Posted February 15, 2008 oskar, why would your rocket would CATO if you drilled too far, maybe it was something with your nozzle? I'm betting that your nozzle had too small a vent hole or that it wasn't thick enough. What were the dimensions of the tube, and did you find the rocket's tube?Increasing the core length increases the amount of propellant available at ignition. Chamber pressure and as a result, impulse, increases. This is typically a way for slower burning powders (ones that give beautiful tails) to be used as rocket propellants.
moonshot Posted February 16, 2008 Posted February 16, 2008 No. Your bp is plenty fast enough. Making a consistent rocket motor that doesn't CATO is a balancing act between propellant speed, nozzle diameter core length and tube strength. Changing any of these will effect the performance of the motor. My advice is to stay with the same propellant and nozzle diameter since you already had one good flight with those and shorten your core length as you already stated. Once you have a successful design record all your data ie. core length, nozzle dia, tube specs and build each motor the same. It looks like your having lots of fun so keep it up and BE SAFE.
oskarchem Posted February 20, 2008 Posted February 20, 2008 Wow, it has been 4 days since I have been on this forum (on vacation in venezuela, missing my lab a bit...) qn I hqve plenty to read. Right so gettig back: Well the nozzle diamiter is ok, but what I wanted to say was that I drilled my core too far, was this: If you drill a long core, the powder bruns much faster, thus the fire reaches the header faster, making it xplode lower.
Mumbles Posted February 20, 2008 Posted February 20, 2008 That is why it is advised to use a delay oskar. Might just be my own personal taste, but headers that go off while still rapidly accelerating up to me look poorer and more amateurisitic. I like a nice roar on take off, coast for a bit, perhaps with a glitter tail, then pop beautiful header breaking fully, and not influenced by it's travel rate.
oskarchem Posted February 21, 2008 Posted February 21, 2008 Yep, I know, but you now this is my maybe 10 rocket and my firs header, from now on I will use delay, also like the sound of the thrust when the rocket goes up...
Mumbles Posted February 21, 2008 Posted February 21, 2008 The two really nice delay formulas I like have titanium and antimony trisulfide in them, other wise I would offer those up to you. I would imagine a cheap glitter like win 20 or something would give a cool effect.
hst45 Posted February 21, 2008 Posted February 21, 2008 oskar, a simple and easily available delay can be made by adding about 15% baking soda (bicarbonate of soda) to your regular milled BP.
FrankRizzo Posted February 21, 2008 Posted February 21, 2008 Sodium bicarb is fairly hygroscopic, so it's not the best choice. Other carbonates like strontium or barium work a bit more consistently over time.
hst45 Posted February 21, 2008 Posted February 21, 2008 Frank, point taken, and of course correct. I make up my motors and seal them in ziploc bags with the ambient air evacuated to minimize moisture absorbtion. I was only pointing out that if you only have access to household chems you can still make a serviceable delay. I've never tried Mumbles suggestion of using a glitter comp., but the idea of adding an interesting effect between motor cutoff and header burst sounds great.
moonshot Posted March 12, 2008 Posted March 12, 2008 Finally got a couple vids of two rockets I fired at New years loaded onto Photobucket. First is a 75g can head rocket.http://i107.photobucket.com/albums/m314/di...icture127-1.jpghttp://s107.photobucket.com/albums/m314/di...=Picture149.flvSecond is a cone cup header rocket.http://s107.photobucket.com/albums/m314/di...=Picture148.flvI'm getting the cannister head rockets dialed in pretty well. Still need to paste the cone head rockets more to get a better break or maybe use a small flash bag.
lnstantkarma Posted March 12, 2008 Posted March 12, 2008 Where do you guys get your sticks for rockets? The only ones I've used were 1/4in dowel rods at menards and I think I can go cheaper. Also while I'm at it is there a rule to balance the stick for the engine? Like put your finger on the stick before the nozzle or something like that _________________________[[[[[[[[> Balance it there?.............^
moonshot Posted March 12, 2008 Posted March 12, 2008 I'm fortunate enough to own a table saw so I cut my own sticks. I use cedar for my sticks because it is light weight and readily available where I live. But it is expensive. In my opinion balancing the rocket on your finger just behind the nozzle is a myth. I have launched 140g rockets with a 32" long stick that only weighs 11g!http://i107.photobucket.com/albums/m314/di...icture128-1.jpg
psyco_1322 Posted March 12, 2008 Posted March 12, 2008 Most people will rip their own sticks from a strong, light-weight wood like pine, usually in the form of 2x4s. They just run it through a table saw and come out with sticks. The balancing act is not a good method of sticking the rocket, it fails and is unnessacary. A good rule is that the stick be 4 times as long and the rocket+header.
moonshot Posted March 16, 2008 Posted March 16, 2008 So I had one 5" tube left and decided to build another can head rocket. This one has a 105g header filled with all my leftovers from New Years. Stars from a couple 1.4g shells and whatever else I could scrounge up.http://i107.photobucket.com/albums/m314/di.../Picture150.jpgI still have to paste the header and glue on the stick. I'm also thinking about adding a cone to help the aerodynamics.http://i107.photobucket.com/albums/m314/di.../Picture151.jpgThe cone could also be used for a double break or to house a "Surprise". And here it is! Locked, cocked and ready to rocket!http://i107.photobucket.com/albums/m314/di.../Picture152.jpgThis has got to be my magnum opus, my masterpiece! I am truly a legend in my own mind! Sorry, got a bit carried away One thing is for sure I won't be standing anywhere near this after it's lit.
ActionTekJackson Posted March 27, 2008 Posted March 27, 2008 Hey guys, I'm using a standard 1lb BP rocket tooling set and I seem to be having an issue with the motor getting stuck on the spindle after ramming the rocket. I do mean stuck, I almost had to destroy one motor to get it off. I recently tried lubricating the spindle with petroleum jelly and twisting the rocket after each incriment. Twisting kept getting harder and harder, it did work better and prevent it from being completely stuck like the one before that. It is possible this is because my tubes are just slightly larger in ID than the tooling set is sposed to have, damn them PVC makers for saying 3/4" when its really not... anywho, I was hoping someone might have some good ideas for how to keep that spindle lubricated well enough to make it easier to remove the rockets. I was thinking graphite powder petroleum jelly mix, but wasn't sure how that might affect ignition.
Frozentech Posted March 27, 2008 Posted March 27, 2008 I was hoping someone might have some good ideas for how to keep that spindle lubricated well enough to make it easier to remove the rockets. I was thinking graphite powder petroleum jelly mix, but wasn't sure how that might affect ignition. I recommend a drylube spray from any NAPA auto parts store ( or probably any auto parts store ). PTFE based, it *really* helps my rockets come off the spindle. Just spray the spindle up with a light coat of it. Never seen any effect on ignition. I also toss about 5% graphite in the bentonite/grog mix I use for nozzles.
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