insutama Posted March 12, 2015 Share Posted March 12, 2015 i got my bottle rocket tooling and i have been making rockets some i made with a clay nozzle and some just bp core i cant really tell the difference whats the advantage of using a nozzle ? Link to comment Share on other sites More sharing options...
Oinikis Posted March 12, 2015 Share Posted March 12, 2015 http://www.amateurpyro.com/forums/topic/10576-sugar-rocket-issues/ Link to comment Share on other sites More sharing options...
Arthur Posted March 12, 2015 Share Posted March 12, 2015 Clay is cheap, other rocket nozzles include polished graphite and asbestos loaded thermosetting resins -neither of which seem to be as cheap as kitty litter! Most or all fireworks are made down to a price then value engineered down more again hence a rocket body is usually paper and clay Link to comment Share on other sites More sharing options...
pyrojig Posted March 12, 2015 Share Posted March 12, 2015 Authur are you reducing your kitty litter before using as a nozzle ? Or are you using it as is? I have found that 5% mineral oil in bento clay seems to hold fairly well for my nozzles. But , cheaper ( kitty liter) keeps the costs low and allows for more rockets to be built . Link to comment Share on other sites More sharing options...
psyco_1322 Posted March 12, 2015 Share Posted March 12, 2015 A nozzle will typically cause you to have higher thrust. Some larger rockets require a tamer fuel for nozzled motors, while nozzleless allows a hotter fuel and less chance of cato. If you are just making small bottle rockets, with a small report header, I'd just keep it simple and leave out the nozzle. Link to comment Share on other sites More sharing options...
insutama Posted March 12, 2015 Author Share Posted March 12, 2015 would i get better altitude with a nozzle ? Link to comment Share on other sites More sharing options...
Arthur Posted March 12, 2015 Share Posted March 12, 2015 If you use a weak BP then you will need a nozzle to get thrust, if you use fast BP then a nozzle may be the cause of catos. You have to decide on some things then discover the rest by trial and error. Link to comment Share on other sites More sharing options...
insutama Posted March 13, 2015 Author Share Posted March 13, 2015 my bp is very fast 1 Link to comment Share on other sites More sharing options...
chand Posted March 24, 2015 Share Posted March 24, 2015 would i get better altitude with a nozzle ?Yes I am sure that you will get high altitude but the problem you will face is that it will create pressure inside combustion chamber so you must use material which is more thick and powerfull enough to hold pressure Link to comment Share on other sites More sharing options...
FlaMtnBkr Posted March 24, 2015 Share Posted March 24, 2015 If your BP is very fast try some nozzleless rockets. Just don't use any clay and use BP as the first increment. You can use as hot of BP as you can make and don't have to tone it down to not get CATOs with a nozzle in place. I find the nozzleless to be more forgiving and easier to make. And with hot BP you can many times lift a heavier payload. If you want to use a nozzle you will likely have to tone down your BP so the pressure doesn't get too high if your BP is really hot. You can make BP with less KNO3 and more charcoal such as 65-25-10 and make the same way. Or you can make your some BP and screen in 5-10% coarse 60-80 mesh charcoal after it comes out of the mill and before you granulate it. You could still get explosions or it might not have enough power and you will need to make further adjustments. Write down what you do do when you get them working well you can make more fuel that is the same. Link to comment Share on other sites More sharing options...
dagabu Posted March 24, 2015 Share Posted March 24, 2015 The dichotomy of the two is that the velocity of the exhaust gasses is greater with a smaller hole for them to escape from and with the clay nozzle, the hole remains the same throughout the propellant burn while the nozzleless "nozzle" immediately opens up regulating the pressures almost instantly thus decreasing the velocity drastically. The conventional though had been that without a choke, the propellant was wasted and no useful thrust could be generated with a nozzleless rocket motor, the nozzle was essential to lift any meaningful weight. Along with better tooling, better ball mills and quality of chemicals, homebrew scales for measuring thrust and therefore impulse were invented, cheapened to the point of affordability and then found their way into the hands of the brave people that wanted to test the difference of the two. These "Test Stands" proved that the same amount of gas was created and curiously, that the impulse was actually much closer than was ever conceived. The obvious result became that the nozzleless motor became the "Lifter" and the nozzled motor became the "Sprinter". All things being the same, the nozzled motor cannot lift the same weight to the same height and the nozzleless cannot lift a lesser weight to the same height as the nozzled motor can. In the end, you want to choose the most efficient motor for the item being lifted. That my friend, is the glory of the chase. Link to comment Share on other sites More sharing options...
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