ActionTekJackson 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. Hmmm... Drylube spray you say... I will certainly check that out, thanks! :-)
moonshot Posted March 28, 2008 Posted March 28, 2008 I found six cone cup headers that I glued up sometime back so I rolled up the tubes to build motors for them. This pic shows the headers on the tubes before they are trimmed and finished.http://i107.photobucket.com/albums/m314/di.../Picture156.jpgThese are based on my 3/8 ID 4" long core burners. I pumped some 3/8"shimzu tiger tail stars for the breaks. http://i107.photobucket.com/albums/m314/di.../Picture153.jpgI test fired the stars from my star gun and the tails were good but they leave a glowing ember. I finally got around to making some Rice Krispies burst charge.(Thanks Godsnight). http://i107.photobucket.com/albums/m314/di.../Picture154.jpgSo thats what these rockets will be loaded with.
justanotherpyro Posted March 28, 2008 Posted March 28, 2008 Ball mill the star comp longer to get rid of the slaggy fallout. It shouldn't kill the tail. I had many a problem with this and after dialing in the ball milling time for my TT fallout is very minimal.
moonshot Posted March 28, 2008 Posted March 28, 2008 Yeah I only milled this enough to mix the comp. The KNO3 was granular and the charcoal was like 20 mesh. But I wanted a slower burning star more like a willow effect. I,ll make one rocket and see how it works.
Apollofrost Posted March 30, 2008 Posted March 30, 2008 I cranked out my first black powder rockets yesterday and boy were they fun to set off. I used 70 20 10 BP from agricultural grade sulfur and kno3 mixed with finely powdered willow charcoal. Unfortunately my non sparking media is still in the mail so I couldn't mill them together, but the rockets worked quite nicely. Here are the stats: 1" id x 2" spiral wound tubes from cannonfuse1/4" kitty litter nozzle w/ 1in core30-35 grams of bp each2' x 1/4in maple dowels for sticks (what I had laying around.) I just had such a blast setting them off, even if they didn't quite fly straight after the first sixty feet. But hey, my first functional rockets that weren't store bought. Yay for me.
moonshot Posted April 1, 2008 Posted April 1, 2008 Yeah Apollofrost it's always exciting to see your first rockets fly! I haven't stepped up to 3/4" ID motors yet but I have my 5/8" ID 5" long core burners tweaked to perfection. Here is my latest contribution to to the realm of high fashion rocketry.http://i107.photobucket.com/albums/m314/di.../Picture158.jpgIt's from my spring/summer lineup. You know when you have progressed to this stage that you have way too much free time on your hands. Keep working on your rockets and stay green!
Apollofrost Posted April 1, 2008 Posted April 1, 2008 It makes me think of 3M for some reason And thanks.
moonshot Posted April 4, 2008 Posted April 4, 2008 Finished sticking up my latest rockets. Magnum Opus ended up being 105g header with a 3g "surprise" in the cone . The others are filled with the Shimzu TT stars and Rice Krispies burst. (Snap, Crackle and BANG!) Also a bump of Goex FFF. http://i107.photobucket.com/albums/m314/di.../Picture159.jpgI double pasted the cones on these so I might get a better throw on the stars. I'll post vids when I can.
KinneticEnergy Posted April 4, 2008 Posted April 4, 2008 Nice work moonshot, I can't wait for the vids!
moonshot Posted April 9, 2008 Posted April 9, 2008 Yet another prototype sky rocket under construction at the Moonshot Rocket Design studio. This one uses my 1/2" ID 4" long core burner motor. http://i107.photobucket.com/albums/m314/di.../Picture161.jpgThis one combines the can and cone into a single unit. ie no top on the can part. Good volume for lots of stars. Still have to think of a way to paste it up . Just finished loading this with TT stars and Krispies burst. http://i107.photobucket.com/albums/m314/di.../Picture163.jpgThis one has all the look and feel of a true classic design. And here it is sticked and finished.http://i107.photobucket.com/albums/m314/di.../Picture164.jpg
Apollofrost Posted April 9, 2008 Posted April 9, 2008 Hmm... I do think I have a wee bit of a problem. My rockets whoosh up into the air with great enthusiasm then they abruptly turn and exit stage right. I think that they either turn once the core has ended or the propellant is exhausted. Straight up for a 100-150feet then whoosh... off to the right. I've never recovered one but it makes me wonder if it's the comp or they're burning off the sticks. Any thoughts or suggestions?
moonshot Posted April 9, 2008 Posted April 9, 2008 Your rockets may be burning through the tube above the nozzle. This would send them flying horizontally. Or you could try a longer stick. It's hard to say without recovering and analyzing a spent motor. Looking at your specs it seems your motors are going to have a very short burn time and be fast. But a 24" stick is too short.
Apollofrost Posted April 9, 2008 Posted April 9, 2008 Oh, I got some new sticks. 4' x 1/4" for the 3"x1" tubes and some just a little thicker for the 1"x6" I think they're 2/5" diameter. Hmm... I'll have to see if I can get a launch site where I can find the rockets afterwards. Maybe the fairgrounds... Thanks a bundle.
Miech Posted April 9, 2008 Posted April 9, 2008 Hmm... I do think I have a wee bit of a problem. My rockets whoosh up into the air with great enthusiasm then they abruptly turn and exit stage right. I think that they either turn once the core has ended or the propellant is exhausted. Straight up for a 100-150feet then whoosh... off to the right. I've never recovered one but it makes me wonder if it's the comp or they're burning off the sticks. Any thoughts or suggestions? I would suggest to use another propellant above the cored part of the motor. When using green powder, some decent meal above the cored part of the engine will usually be enough, otherwise you need another composition. I had some succes by making the cored part with propellant poor in sulfur content, and making the uncored part of fast meal powder. The composition I used for te cored part is as follows: 72 KNO322 Charcoal06 Sulfur It is considered a low impulse propellant, and its burning rate is not very pressure dependant. This has as a side effect reducing the chance of getting a cato. It must be sufficient fine to give good results, which means it has to be ball milled for at least half an hour. For an 18 mm ID motor, a 3/4 core and a 3,5 mm venturi (hole in nozzle) gave me exellent results, but this fully depends on your way of building these motors. I would suggest to do some static tests first, with varying designs, to see what your optimized motor would look like.
psyco_1322 Posted April 10, 2008 Posted April 10, 2008 Oh, I got some new sticks. 4' x 1/4" for the 3"x1" tubes and some just a little thicker for the 1"x6" I think they're 2/5" diameter. Hmm... I'll have to see if I can get a launch site where I can find the rockets afterwards. Maybe the fairgrounds... Thanks a bundle.If you shoot at night you could tape a LED with two button batteries to the bottom of the stick and watch it as it flies and falls, ive done it before.
Apollofrost Posted April 10, 2008 Posted April 10, 2008 I'm thinking that my mix is just straight up too hot for the sticks. It's straight 75 15 10 willow that's been ball milled together for over 24hrs. I'll try and recover some from my next shoot. The one problem I see with burning through the side of the tube is that I have static tested a half dozen or so and never had a cato or burn through the side of the tube. Yet every rocket I shoot veers off to the right after a bit. I'll try some marking ideas.
InRainbows Posted April 10, 2008 Posted April 10, 2008 Apollo, how are you making your cores? If your drilling, even a little bit off might make it fly to the right after there's a hollow space between nozzle and fuel. If your ball milling your black powder, how long are your cores, if none? And if it's your sticks, maybe you could varnish them in something.
moonshot Posted April 11, 2008 Posted April 11, 2008 Obviously burn through isn't the problem if you have tested your motors statically and found none. The strength of your propellant shouldn't have any bearing on making your rockets veer to the right or left. It has to be a question of the thrust angle being changed, possibly through nozzle erosion or your sticks are not straight or the stick angle is changing due to it coming loose during the flight.
Frozentech Posted April 11, 2008 Posted April 11, 2008 Hmm... I do think I have a wee bit of a problem. My rockets whoosh up into the air with great enthusiasm then they abruptly turn and exit stage right. I think that they either turn once the core has ended or the propellant is exhausted. Straight up for a 100-150feet then whoosh... off to the right. I've never recovered one but it makes me wonder if it's the comp or they're burning off the sticks. Any thoughts or suggestions? Well, this might seem like an obvious or stupid question, but is it windy at the altitude where they shift direction ? Rockets notoriously fly *into* the direction of the wind, as the stick points downwind like a weathervane.
psyco_1322 Posted April 11, 2008 Posted April 11, 2008 Wow full strength willow bp should be tearing your rockets in half unless you have any oversized nozzle or somehow have really crappy bp.
TheSidewinder Posted April 11, 2008 Posted April 11, 2008 Agreed. I made a batch of Willow BP last year, also milling 24 hours, and it was scary fast. Made great lift, though.
Stinger Posted April 12, 2008 Posted April 12, 2008 Hi The clue to get BP rockets with ball milled BP straight up in the air is to use no core.Just drill the noozle till you touch the BP. I made a rocket exactly like that (a silver comet on top): http://www.apcforum.net/files/S8000006.AVI Tube was 3" long and the ID of the tube was 1/2".Noozle was 3mm ID. Stinger
Apollofrost Posted April 12, 2008 Posted April 12, 2008 Fun fact, apparently my housemate heard one of my rockets launch from two blocks away. I didn't think it was really that loud... I'll think about everybody's suggestions and make a new batch of rockets when I have the time. In the mean time thank you guys for the input.
BPinthemorning Posted April 12, 2008 Posted April 12, 2008 I'm trying to make rocket tooling that will fit pant hanger paper tubes. I'm talking about the thin paper tube on PANT hangers. Any recommendation for core length, nozzle withs and how long should i cut the tubes? All answers appreciated.
ActionTekJackson Posted April 13, 2008 Posted April 13, 2008 I'm trying to make rocket tooling that will fit pant hanger paper tubes. I'm talking about the thin paper tube on PANT hangers. Any recommendation for core length, nozzle withs and how long should i cut the tubes? All answers appreciated. uhm... just a question of curiousity, but... why would you want to do this? Are reinforcing the tubes by any chance? I dunno about the hangers ur getting, but the one's I've seen don't have very good tubes, they're usually pretty smashed, and thin. Dunno about the tooling dimensions though, I believe there are some formulas earlier in this thread that are pretty safe for BP Rockets.
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