eggi96 Posted June 27, 2011 Share Posted June 27, 2011 Hi guys tonight I launched my first core burner rocket with a 2 inch tiger tail header using my homemade tooling http://www.pyrobin.com/files/dsc_0172.jpg which I constructed using nighthawkinlight's video The rockets I.D is 19mm and 100mm length. it didn't quite go as planned the rocket lifted up to a height of 2 metres (i think) I couldn't really see I was far away then ignited the header. The header worked perfectly but the rocket engine didn't. Is my rocket tooling flawed or do I have to mill my bp for longer Link to comment Share on other sites More sharing options...
mabuse00 Posted June 27, 2011 Share Posted June 27, 2011 I couldn't really see I was far away then ignited the header.You need to know what happens. The motor might might have exploded, thus skipping the delay, or it just did not have enough power for liftoff. Don't go too far away. I use sand dummys with a very small H3 salute for such tests, so I don't need to worry about the header. If it does not liftoff just use a more lean mixture, if it explodes add more charcoal. IMHO super fine milling is not required. It's much more important that you can reproduce your fuel grade, keeping the quality as constant as possible. Link to comment Share on other sites More sharing options...
stckmndn Posted June 27, 2011 Share Posted June 27, 2011 Tell us about your fuel mix. Link to comment Share on other sites More sharing options...
DeepOvertone Posted June 27, 2011 Share Posted June 27, 2011 Yes Tell us about your fuel. You should be able to get away with 75/15/10 using commercial airfloat and +10-20% coarse charcoal. That doesnt even need to be milled at all. Just the Kn03 milled fine then rough mixed with sulfur and charcoal. That works fine for me. But I'm using professional tools. If your motor did indeed CATO it could be because your tooling didnt allow you to get a compact enough fuel grain. Link to comment Share on other sites More sharing options...
eggi96 Posted June 28, 2011 Author Share Posted June 28, 2011 I use 60/30/10 ratio for my bp. It has been milled for 3hrs. I use homemade willow charcoal. I dont think the motor exploded since my header lit. It might be because I used visco fuse fused at the end and didnt use blackmatch Link to comment Share on other sites More sharing options...
allrocketspsll Posted June 28, 2011 Share Posted June 28, 2011 do inground test till you get it right then put a header on one but you have lots to figure out first,it will be a learning experience but well worth the effort mate good luck Link to comment Share on other sites More sharing options...
eggi96 Posted June 28, 2011 Author Share Posted June 28, 2011 ok yep nws ill have to do some tests and see what the problem is. Thanks guys for the help Link to comment Share on other sites More sharing options...
dagabu Posted June 28, 2011 Share Posted June 28, 2011 Eggi, Try a leaner mix, 75:15:10 is a good place to go without a nozzle to test your rocket fuel. If it is strong enough, the rocket will fly very well but will not CATO. Listen to the burn, it should be a strong WHOOSH sound ans burn for about 2 seconds. If it burns for three seconds or longer, you have a poor fuel and you need to change your chemicals, probably your charcoal. Lots of beginners think that lump charcoal briquettes or activated charcoal will work just fine but it will not. If you cant make your own charcoal, buy Cowboy Brand lump charcoal, and while it is not the best, you will make very passable charcoal. -dag Link to comment Share on other sites More sharing options...
Mumbles Posted June 28, 2011 Share Posted June 28, 2011 The 6:3:1 mix is normally just screened. Your mix in theory should have a little more oomph behind it. However, this is counter acted by the fact that your tubes are about half the normal size. Shorter tube, shorter core, less power. It's very hard to help if you don't know exactly what happened, or at least have a good idea. Was the rocket slow to take off, or did it seem like it started out pretty well? There are two options that could be at play. Either something involving your tooling or fuel is less than adequate and it didn't have enough lift, or those are fine and the bulkhead blew through and lit the header prematurely. Were you able to find the casing afterwards to examine it? That would easily be able to tell if it was a true CATO or some other sort of malfunction. A slow take off could be a result of the fuel, or your nozzle blowing out. It's been mentioned before, but without a standoff inside the tube to add a small recess before the nozzle, it is much more likely to blow out. It also allows for angled vents on the nozzle, which can improve thrust and decrease errosion. Link to comment Share on other sites More sharing options...
eggi96 Posted June 28, 2011 Author Share Posted June 28, 2011 This launch was done at night so Im not sure where it landed but ill do another test in the day so I can inspect its performance . The motor sounded good but Im not sure il do another test then report back Link to comment Share on other sites More sharing options...
drthrust Posted June 28, 2011 Share Posted June 28, 2011 (edited) hello, ask ten rocket guys a question and you'll get ten different answers! personally, from my experiences, your tooling's out, what you've got there is known as a "shorty" motor, which need more exotic propellants than bp to perform, ie whistle, and hybrid mixes. cool your charcoal down, i reserve willow only for my nozzle-less motors , go for pine ( best tails in rockets) ,and aim for 7.5"- 8" casing with a spindle length of 5"- 5.5" for a 19mm/ 1 lb motor.i tried a few bp shorties myself in an attempt to cut down weight and stick length but to no avail Edited June 28, 2011 by drthrust Link to comment Share on other sites More sharing options...
dagabu Posted June 29, 2011 Share Posted June 29, 2011 hello, ask ten rocket guys a question and you'll get ten different answers! personally, from my experiences, your tooling's out, what you've got there is known as a "shorty" motor, which need more exotic propellants than bp to perform, ie whistle, and hybrid mixes. cool your charcoal down, i reserve willow only for my nozzle-less motors , go for pine ( best tails in rockets) ,and aim for 7.5"- 8" casing with a spindle length of 5"- 5.5" for a 19mm/ 1 lb motor.i tried a few bp shorties myself in an attempt to cut down weight and stick length but to no avail Make that 11 I make shorties all the time, in fact, I have end burners 7" long by 1" ID that fly very well with a 24" stick high enough to throw out a few stars at apogee. You Brits must have slow charcoal. Good to see you back here Thrust, nice to see the Dr. is in the house. -dag Link to comment Share on other sites More sharing options...
eggi96 Posted June 29, 2011 Author Share Posted June 29, 2011 im going to make new tooling to what the rocket sketcher specifies for 19mm I.D rockets then I will see if there is a change Link to comment Share on other sites More sharing options...
dagabu Posted June 29, 2011 Share Posted June 29, 2011 im going to make new tooling to what the rocket sketcher specifies for 19mm I.D rockets then I will see if there is a change Its not your tooling, I promise! -dag Link to comment Share on other sites More sharing options...
eggi96 Posted June 29, 2011 Author Share Posted June 29, 2011 i just might have built the nozzle up a bit too much when I think back on it since i went overboard a bit that might have been the problem ok dagabu i will try fixing other variables and if all comes to worse i will make new tooling Link to comment Share on other sites More sharing options...
dagabu Posted June 29, 2011 Share Posted June 29, 2011 The nozzle throat does not need to be any deeper then 1/2 ID if consolidated well or 1 ID if hand ramming (some do better then others). -dag Link to comment Share on other sites More sharing options...
drthrust Posted June 29, 2011 Share Posted June 29, 2011 dag ,you've managed to perfect bp core burner shorties ? end burners are about 5" long for a 1lb'er, but i wouldn't have thought there'd be enough fuel in a 4" long 1lb core burner?so the tooling's out if your starting out with rockets go with the age old tried and tested tooling designs until you get a feel for it, then experiment with spindle lengths, say + 0.5", or -0.5" at a time to find a motor that suits you.sorry dag but there's another shark in the tank now Link to comment Share on other sites More sharing options...
stckmndn Posted June 29, 2011 Share Posted June 29, 2011 This is why I think spending $120 for pro tooling is a bargain. You may flame me now. Link to comment Share on other sites More sharing options...
portfire Posted June 29, 2011 Share Posted June 29, 2011 It's nice to see the good doctor here Link to comment Share on other sites More sharing options...
eggi96 Posted July 3, 2011 Author Share Posted July 3, 2011 commercial tooling cost way too much Link to comment Share on other sites More sharing options...
Mumbles Posted July 3, 2011 Share Posted July 3, 2011 This isn't a cheap hobby buddy. I assure you that commercial tooling is worth it if you don't have the ability to turn your own. Link to comment Share on other sites More sharing options...
dagabu Posted July 4, 2011 Share Posted July 4, 2011 dag ,you've managed to perfect bp core burner shorties ? end burners are about 5" long for a 1lb'er, but i wouldn't have thought there'd be enough fuel in a 4" long 1lb core burner?so the tooling's out if your starting out with rockets go with the age old tried and tested tooling designs until you get a feel for it, then experiment with spindle lengths, say + 0.5", or -0.5" at a time to find a motor that suits you.sorry dag but there's another shark in the tank now Dr. Thrust, Yes, shorty endburners are actually easy to make, list no more then 10% of the entire rocket with stick and I get consistent heights of 200-300' with short 1# rockets. This is why I think spending $120 for pro tooling is a bargain. You may flame me now. No flaming here stickman but I make tooling for less than that, a two rammer set with the "super" BP spindle and universal base is $75.00 from me. It's nice to see the good doctor here commercial tooling cost way too much See the above reply, it does not have to be that expensive, trust me. -dag Link to comment Share on other sites More sharing options...
stckmndn Posted July 5, 2011 Share Posted July 5, 2011 This is why I think spending $75 for pro tooling is a bargain. (I ordered 1 lb end burner tooling from Dag) Link to comment Share on other sites More sharing options...
drthrust Posted July 6, 2011 Share Posted July 6, 2011 its a great service your providing for your fellow pyro's dag, how do you over-come turning long tapers?, by offsetting the tail stock, or are you posh and have a taper turning attachment? Link to comment Share on other sites More sharing options...
dagabu Posted July 6, 2011 Share Posted July 6, 2011 its a great service your providing for your fellow pyro's dag, how do you over-come turning long tapers?, by offsetting the tail stock, or are you posh and have a taper turning attachment? WHAT??? And give away all my tricks?!? Easier then that, I use simple math, say the nozzle is 20mm and the spindle tip is 10mm, I cut the spindle down in steps of .5mm each pass times whatever length the spindle is. That way I can then hand turn the steps to a smooth angle and then use a file to smooth any scratches out. 120, 240, 600 grit sandpaper followed by Mothers Mag Polish makes for nicely straight spindles but with the hand made feel. I like brass the best, aluminum second and SST is simple EVIL! -dag Link to comment Share on other sites More sharing options...
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