Sparx88 Posted November 16, 2015 Posted November 16, 2015 I'm looking around for 2 stage black powder designs. I don't even want to look at youtube. I am wanting to learn these in the 2-8oz sizes. Good experienced help required but not un-needed I have tools for 1/4", 5/16", 3/8", 7/16", 1/2" and 5/8". I got a 1" set but won't be doing those in 2 stage.
Maserface Posted November 17, 2015 Posted November 17, 2015 (edited) Never hurts to google http://www.amateurpyro.com/forums/topic/10565-dual-stage-rockets/http://www.amateurpyro.com/forums/topic/8342-stick-lengths-and-position-for-2-and-3-stage-rockets/http://www.amateurpyro.com/forums/topic/6262-information-on-multistage-rockets/http://www.amateurpyro.com/forums/topic/4779-stage-whistlerockets/ Edited November 17, 2015 by Maserface
mikeee Posted November 17, 2015 Posted November 17, 2015 I have made two stage rockets with the stick attached to the top motor and a slip fitinternal coupling between the motors. The thrust of the 1st motor holds the 2 stages together during the 1st motor burn, the second motor ignites and and ejects the 1stmotor from the rocket the and 2nd stage continues its flight with the rocket stick attached.
calebkessinger Posted November 18, 2015 Posted November 18, 2015 Plastic shipping tape works fine to hold the first stage on. Just one nice wrap. Put very little delay in the first stage. Think more like triple whistle rocket. Zip! Zip! Then delay. You can add more delay to them after you see how they turn over in flight
Sparx88 Posted November 18, 2015 Author Posted November 18, 2015 Ty for the info. I did have some that I found just searching around but wanted to hear from you guys too. The slip fit seems to be working better than having the motors fixed. I started with painters masking tape to hold the first stage but it looses grip after a few minutes and the motor became unstable. Regular masking tape is ok but wrinkles easy. Will be picking up some plastic shipping tape to try that. Now how much overlap should I be using on each motor using the plastic shipping tape? I will for sure be trying everything on 2 Oz motors. Also do you guys ever use fast fuse yellow 2mm 4sec/ft to transfer fire to the second stage? Is that advisable? I tried back drilling the delay on the first stage sort of a real short core and that worked too. It'll shoot fire like a fountain for a split second right into the 2nd stage. It's just that there's no guarantee that it will work all the time since there's no mechanical or direct contact. Like target shooting. These motors have a pretty small nozzle 1/8".
calebkessinger Posted November 18, 2015 Posted November 18, 2015 I made quite of few 1/2in motors. Just put a little bp on top of the delay to ensure ignition of the next motor. One wrap of plastic tape works perfect. the overlap is a non issue once the heat hits it from between the motors it melts away. Getting it more than one layer thick would be an issue. Have fun and GET SOME VIDEO !!!
dagabu Posted November 20, 2015 Posted November 20, 2015 You can also make two nozzleless motors and just tape them together on the same stick... The first motor ignites the second and it just pushes the thrust through the first tube. No worries about staging or separation. I launched 50 of them at PGI this past year and another dozen at BOOM!Town. They work every time with no extra work, just make sure to NOT use a clay bulkhead and keep the delay to 1 diameter of the motors fuel. Good luck!
Sparx88 Posted November 20, 2015 Author Posted November 20, 2015 Thats close to what I was going to try as well Dag. Though I would have to use hot fuel because my main fuel recipe is set in stone and it works with all the rockets with nozzles. I got it tuned to just below the point of blowing out the ends. I was making nozzless rockets a few months back with paulownia bp but it seems like they lose thrust power very quickly. If I even cough the word nozzle around that paulownia stuff it's bang time instantly lol. I think going with a nozzled on 1st stage, then nozzless second.Give me a couple days and I'll have a few videos and pics.
dagabu Posted November 20, 2015 Posted November 20, 2015 Think about nozzleless on the bottom (first stage) with a hot fuel and using the dialed in nozzled rocket on top. It works! 1
Sparx88 Posted November 21, 2015 Author Posted November 21, 2015 You know, that makes more sense to do nozzless 1st, nozzle second. Using that paulownia fuel. See what it is, I only make standardish bp with it, 77-15-10, which is why it catos with nozzles, super fast stuff. With a nozzless motor, it works very well with a lot of power. But with the tooling I'm using for 1/2 and 5/8, they get a 2 1/2" x 1/4" core is all. Tubes are 4" long. So yah, thats what I mean when I say they loose thrust pretty fast is because of the short core. But what power it gives it gives it fast and the rockets take off like a shot. So I'll have to make another tool to give them a longer core to get a longer burn I think.Just rolled up some more tubes and am going at it.
stix Posted November 21, 2015 Posted November 21, 2015 Think about nozzleless on the bottom (first stage) with a hot fuel and using the dialed in nozzled rocket on top. It works! What dags has described seems like a great way to go - lots of grunt on the first stage to get the mass moving with good acceleration, then the nozzled (end burner) kicks in for the second stage. The second stage being an end burner will be more of a sustained thrust over a longer period, adding to the overall height reached. Not that it wouldn't work with both stages being nozzlesess, but my preference would be for the former. ... I'll have to make another tool to give them a longer core to get a longer burn I think... Sparks, if you're talking about a core burner, then giving them a longer core (internal bore) will increase the thrust and therefore reduce the burn time (cato?). For a longer burn time on a nozzleless variety you will need to dial back your fuel or press it more. Sounds like fun though. Cheers.
dagabu Posted November 28, 2015 Posted November 28, 2015 Sparks, if you're talking about a core burner, then giving them a longer core (internal bore) will increase the thrust and therefore reduce the burn time (cato?). For a longer burn time on a nozzleless variety you will need to dial back your fuel or press it more. Sounds like fun though. Cheers. Nope, not with BP. The actual burn time for your average BP rocket (no delay included) remains pretty static with nozzleless motors. Tests show that the same duration exists with a short or long spindle.
stix Posted November 29, 2015 Posted November 29, 2015 (edited) Nope, not with BP. The actual burn time for your average BP rocket (no delay included) remains pretty static with nozzleless motors. Tests show that the same duration exists with a short or long spindle. Ah yes, correct you are dags - I did read that somewhere. I was thinking of sugar rocket fuel (r-candy) which increases in burn-rate under pressure. So re-wording my original statement for clarity, would this be correct?:A longer core (spindle) nozzled OR nozzleless, will not produce a longer burn time with bp or r-candyIf you're talking about an r-candy core burner with a nozzle, then giving them a longer core (internal bore) will increase the pressure/thrust and therefore reduce the burn time (cato?)For a longer burn time on a nozzleless variety (bp or r-candy) you will need to dial back your fuelConsidering the original question was regarding bp, then point two can be ignored. Edited November 29, 2015 by stix
dagabu Posted December 8, 2015 Posted December 8, 2015 Yupper, R-Candy will burn faster as the pressure increases, whistle does this as well.
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