Boomer Posted December 4, 2006 Posted December 4, 2006 Have you thought about 2-part epoxy? Yes I know you need too much to get a paste, but you could thin the separate components with say ethanol, mix it with the powder, then let evaporate. The two crumbly residues would be worked into each other, then pressed. This would allow much less to be used, so that it just fills the space between the particles. At high pressure, this to-be-filled space could be as little as 3%. Might still need adjusting the oxidizer ratio though. Just a thought. Somewhat like the PBX types with over 95% HMX and just a little estane or whatnot.
shadopyro Posted December 4, 2006 Posted December 4, 2006 I'm guessing that the 3% added epoxy is somewhat similar to whats used with the commercial model rocket engines?
Boomer Posted December 5, 2006 Posted December 5, 2006 I don't think they use a 2-component plastic binder, rather just dextrine and a very hefty hydraulic press. Correct me if I'm wrong. Of course there are epoxy bound motors, but they are not BP based IIRC, rather AP based, with the epoxy the fuell (plus metal at least in some comps). Again not really my area of knowledge, look at the composite propellant thread.
moonshot Posted December 28, 2006 Posted December 28, 2006 heres a shot of some things I'm working up for New Years. The two rockets on the left are fin stabilized missiles I built using ideas posted on the forum. The ones on the right will be stick stabilized. They have 4" long 1/2" ID core burning motors with nozzles. I just need to paste and load the headers and secure the sticks.http://i107.photobucket.com/albums/m314/dickwad_07/Picture046.jpg
ewest Posted December 28, 2006 Posted December 28, 2006 Please if you can, get some videos of the fin stabilized ones. I'm really curious to see if they work or just fall over and shoot along the ground. Hopefully NOT, but you never know with rockets. If they do work I might try some for the 4th next year, they just look so cool.
moonshot Posted December 31, 2006 Posted December 31, 2006 Heres a pic of the finished four rockets in the previous picture.http://i107.photobucket.com/albums/m314/di.../Picture057.jpg the headers are pasted with paper bag and loaded with 35 grams of cut TT stars and homemade BP with some commercial 3fg to give the break some kick. I hand build all the components for these rockets including the tubes, headers, sticks and the tooling to ram the motors. It takes some extra time and effort but the performance derived is worth it. Now after saying all that I hope the damn things don't CATO on lift off. I will try to get some decent video of them. Until then everybody have a safe and happy PYRO NEW YEAR!
Pretty green flame Posted December 31, 2006 Posted December 31, 2006 They look absolutely amazing. Have a happy new year with loads of succesfull pyro everyone.
Aquarius Posted March 5, 2007 Posted March 5, 2007 Old thread but much knowledge here...Just wanted to share my results with using Waterglass in my claymix. I use "a bit" of waterglass just to get the mix damp. And I have tried straigt bentonite, bentonite and balsting sand and bentonite and charmotte/fireclay. As long as the particles are the same (fine) mesh, it make superior nozzles. Nowadays I prepare all my tubes with nozzles first, leave them for a few days and then start fueling them. The nozzles are rock hard and expand a bit, but it makes for a very cosistent nozzle. 1
moonshot Posted March 6, 2007 Posted March 6, 2007 Hey aquarius I test fired my 15mm ID 130mm long rocket motor with the 70 gram header. Here is a pic of the results.http://i107.photobucket.com/albums/m314/di.../Picture087.jpg It blew out both the nozzle and the plug. Looks like I'm going to have to reverse engineer it I know you mentioned on the tooling thread that you had the same problem with your 15mm ID core burner and you had shortened your spindle 10mm and gotten it to fly. What dimensions did you end up with for nozzle diameter and spindle length? I know these will be great motors when I get them flying. I didn't get a pic of the CATO but it was pretty spectacular. shot the stars a good 35-40 feet high. Always follow the golden rule of pyro. Light fuse and GET AWAY! The good news is the tube held up to pressure.
Aquarius Posted March 6, 2007 Posted March 6, 2007 I use a nozzle diameter of 6 mm, a spindle length of 70 mm and quite sturdy 15 mm id tubes made of manilla file folder. My fuel is 70:20:10 + 10 % charcoal. Not very reactive C, it's BBQ charcoal but it works great and it's another "locked" factor. Gives a long and full orange tail. Plain 70:20:10 is too powerful on the 15 mm, but works like a charm on my 12 mm. The 15 mm lifted a rather large model rocket to a hight were it was lost of sight and never recovered (2. time...) I have yet to test these motors on a static testbench I'm building.But with these results, I guess both motors are quite powerful.We'll se. Try your own advice: Cut down on the spindle length. I know that in a 5 mm nozzle 70 mm is about max on my fuel, and with a 6 mm nozzle, 70 mm is quite safe (depending on your fuel).
moonshot Posted March 7, 2007 Posted March 7, 2007 Yeah. I will try 70mm long with a 6mm Nozzle ID. I also want to try your idea of dampening my nozzle mix with water glass solution.It seems that would also help the nozzle adhere to the tube wall better. I know I get a fair amount of erosion on my straight kitty litter nozzles. I have a large ceramics supply store close to me so I will check them out for the water glass and some bentonite also some powdered fire clay and try a mix with that. Anyway it's back to the drawing board for this project.
Caramanos2000 Posted April 4, 2007 Posted April 4, 2007 I wana make some with the 5 cent rocket formula and some Bp. I made a ramming station with nails epoxied to a board as the spindle. Using cat litter for nozzles. What is the best way to grind it? I should ram it the same way with both formulas right? Also I would like to know if these tubes would work http://pyrocreations.com/inc/sdetail/748 ?
Mumbles Posted April 4, 2007 Posted April 4, 2007 To grind the cat litter, a blender or coffee grinder is probably best. I would not recomend those tubes for rockets. They are spiral wound. Ramming them will result in them unraveling and splitting. They are also nowhere near long enough for BP rockets. I'd suggest getting some parallel tubes. Skylighter, firefox both sell them. Jim Biersach sells them too, but must be cut to size. They are some of the highest quality tube available anywhere.
Caramanos2000 Posted April 4, 2007 Posted April 4, 2007 I tried them with unground rammed litter, and the Nickle rocket formula. Static tests. With the tubes above. They seem to have loads of thrust and sound horifying for about 1 to 2 seconds. Also, there is about a 3/4" gap on the top of the tube big enough for payloads. Will slap one on a stick a try it out. Tubes didnt split.
Mumbles Posted April 4, 2007 Posted April 4, 2007 For the sugar rockets they might work. For BP I highly doubt it. For core burners, they are way too short, and for an end burner, they are still pretty short. Sugar rockets don't need to be rammed that hard, but for BP, if the tubes arn't splitting or bulging, you're not ramming them hard enough.
Caramanos2000 Posted April 4, 2007 Posted April 4, 2007 Cool, i have only used the sugar formula so far. I will film it so you can see it and tell me if its fast enough for actual flights. The core is 1/8".http://s104.photobucket.com/albums/m171/Ca...tStatictest.flv
cplmac Posted April 4, 2007 Posted April 4, 2007 It's hard to tell from that video. Seems energetic enough, what was the ID?
Caramanos2000 Posted April 4, 2007 Posted April 4, 2007 I just tried Green mix, um BAD IDEA. I have never seen such a large Bp explosion. The cato was spectacular lol. Nothing left. The tube in the video is this one http://pyrocreations.com/inc/sdetail/748. The ID is 3/4".
hst45 Posted April 5, 2007 Posted April 5, 2007 In a BP rocket try upping the ratio of fuel to oxidizer, for which read "add charcoal. " The addition of only 2 or 3 percent can have a significant impact on performance. This should slow the burn rate down, and has the collateral benefit of adding a rather attractive spark-trail. Also, make sure to ram or press your grain TIGHT as Mumbles advised. Loose = CATO, tight ="WOW!"
Aquarius Posted April 5, 2007 Posted April 5, 2007 I just wanted to share a bit of my work on 12 and 15 mm drivers. My 12 mm driver has a nozzle of 5 mm and a spindle of 65 mm, a total length of casing is 100 mm. Fuel is 70:20:10 ballmilled 6 hrs, wetted and granulated, as well as a slower fuel with 10 % more charcoal. Works very well. My 15 mm driver has a nozzle of 6 mm and a spindle of 70 mm, a total length of casing is 110 mm. Fuel is 70:20:10 + 10 % C, ballmilled 6 hrs, wetted and granulated. I use a LaValle nozzle (60/30 degr) with bentonite and charmotte with a bit of waterglass to make it harder. The 15 mm lifted a dummy load of 195 grams to a ok height (maybe 200 feet, hard to tell without tig.calc) with a very nice tail.
Caramanos2000 Posted April 6, 2007 Posted April 6, 2007 Has anyone bought from http://www.freewebs.com/supremepyro/index.htm . Want to order the 15mm kit, were else can i get it from?
moonshot Posted June 10, 2007 Posted June 10, 2007 Here is a pic of my latest rocket. http://i107.photobucket.com/albums/m314/di.../Picture088.jpgSpecs are 130mm long tube hand rolled, 15mm ID and 4mm wall thickness. Rammed on homemade tooling 70mm long core, 4mm core ID. I reamed the nozzle ID out from 4mm to 6mm with a drill bit. The first one of these that I made blew out the nozzle and end plug hence the larger nozzle ID. 71/24/5 BP mix for propellant. I just fired one of these from my backyard and it flew great. Nice loud whoosh on ignition and great spark tail. Must have hit 250 to 300 feet. The header has enough volume for a good size break. This is probably the largest size BP motor that I will build. Now it is time to make some colored stars! happy pyro everybody and have a good July 4th if your in the USA.
Aquarius Posted June 10, 2007 Posted June 10, 2007 That one looks great, I use the same spec's On 70:20:10 my 15 mm lifted 200 grams deadweight, so it packs a hefty punch for a small and easy rocket!
moonshot Posted June 11, 2007 Posted June 11, 2007 Yeah Aquarius I got this size motor to work on the second try. Just had to shorten my spindle and increase the nozzle ID to drop the pressure of the initial ignition so it doesn't blow the ends out. You mentioned that you have boosted up to 200 grams to good heights with your motor that is very close to the same size. I'm planning on building some with cannister shell headers in the 90 to 100 gram range. I will try to document the build process and post pics and vids. And your right these will make for an impressive skyrocket. Now it is time to roll up some tubes since I already have 200 grams of propellant, sticks and material to make the headers. So it's back to work for me!
Aquarius Posted June 11, 2007 Posted June 11, 2007 Well the 200 g "live lifting" was a lead fishing weight (not including the rocket) and it was with a 70:20:10 + 10 % coarse charcoal. I could not trig the height out, as I wanted to be sure it landed in water... Now that I have my nozzle and tube thickness sorted out, I'll do another test. It will probably lift a bit more with the 70:20:10, have only done static tests so far, and my digital test stand is waiting to be built. If you have the time, it would be nice to see how you make your motors, maybe we'll all learn something.
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