PyroNinjaah Posted September 14, 2016 Posted September 14, 2016 -Hello, I have been reading all of the information on this sight quite extensively and have really progressed far in the art of Pyro. I have recently began making rockets and have already made some nice 1/2" End-burning black powder rockets and such, however, I can't seem to find the common dimensions for all the sizes.-I do know the common length of tube that corresponds to the ID of the rocket as posted on Skylighter at http://www.skylighter.com/fireworks/help/black_powder_rocket_engine_sizes.asp Are these lengths of tubes generally the same for core and end burners, or are end burners shorter, and if so, by how much. -Also, I was wondering about the tube thicknesses and nozzle diameters. I think I remember there being a 1/4 rule or something, but I'm not certain. In addition, are the nozzle diameters the same for core burners and end burners or different?-Final question: is there also a general rule for the core length compared to the overall length in a core burning rocket. --If any of you could provide any answers, general rules, and/or specifications for common rocket sizes, that would be great and very helpful. -Thank you very much.
dagabu Posted September 14, 2016 Posted September 14, 2016 PyroNinjaah, I think that you are asking for a whole lot of information here, it would take many of us hours to answer your seemingly simple question so instead, i propose this: Read through the rocket forum section here, read a little, answer some of the questions yourself so that you have an understanding, not just an answer.
OldMarine Posted September 14, 2016 Posted September 14, 2016 I'm pretty sure I have a pdf somewhere that lists most of the information the OP is looking for. I asked most of the same questions (not all in one post) when I started dabbling in rockets.Unfortunately it seems I didn't rename the file or the other several hundred I have saved I my tablet but I'll look through them if I have down time tomorrow.
PyroNinjaah Posted September 15, 2016 Author Posted September 15, 2016 Thank you for your reply. As far as asking a lot, I know I am, but I have spent numerous hours googling this and can't seem to find the answers I'm looking for. My hope was to find all the basic getting-started rules so that they're all in one place for others in my position. I have used the search funtion and renamed what I'm looking for countless ways but to no avail. However, the information is on this great website. After spending the last 4 hours going through probably 30 of the 750 rocketry posts, I have found most of my answers.
PyroNinjaah Posted September 15, 2016 Author Posted September 15, 2016 What I found was: -The tubes are 10xID, consisting of a wall thickness of 1/4xID.-The length of paper to roll the tube = (pi)(W/P)(ID+W) where W = the desired wall thickness and P = the paper thickness.-The nozzle diameter for end burners are generally 1/4xID.-Cored rockets generally have a nozzle between 1/2 and 1/3xID- The spindle length is 7xID in core burners -- So my revised, shorter list of questions are:-are the rules above correct and generally true?-Is there an advantage for using the normal long tubes for end burners? I have seen a lot of end burners with smaller lengths than the standard.-Are these rules mostly just starting points and Ok to be adjusted until it flies good, or are these rules the most efficient with the best performance or something?-Thank you. 1
NeighborJ Posted September 15, 2016 Posted September 15, 2016 Ninja, the search function on this site has something to be desired. If you search in Google for the specific type and size motor, you should find the most relevant thread on this site. The search function here only really searches thru titles of threads and most threads will start as one topic and end up on a different subject all together. By the way, what size and type motors are you planning on making? Try to narrow it down to one at a time.
OldMarine Posted September 15, 2016 Posted September 15, 2016 What I found was:-The tubes are 10xID, consisting of a wall thickness of 1/4xID.-The length of paper to roll the tube = (pi)(W/P)(ID+W) where W = the desired wall thickness and P = the paper thickness.-The nozzle diameter for end burners are generally 1/4xID.-Cored rockets generally have a nozzle between 1/2 and 1/3xID- The spindle length is 7xID in core burners -- So my revised, shorter list of questions are:-are the rules above correct and generally true?-Is there an advantage for using the normal long tubes for end burners? I have seen a lot of end burners with smaller lengths than the standard.-Are these rules mostly just starting points and Ok to be adjusted until it flies good, or are these rules the most efficient with the best performance or something?-Thank you. You just asked my same questions from a year ago! The simplest answer I've found is to get quality tooling and experiment... Oh yeah, and experiment some more.
dagabu Posted September 15, 2016 Posted September 15, 2016 -Are these rules mostly just starting points and Ok to be adjusted until it flies good, or are these rules the most efficient with the best performance or something? Hmmm, not really rules, more of "standards" if you will. The tube wall thickness for example, NEPT tubes come in two wall thicknesses, the standard is 1/8" wall thickness, it's the same for most of the smaller diameter rockets of many sizes. Rolling your own? Yes, I am good with the 1/4" ID as a general rule. The spindle length of a "traditional" black powder rocket, nozzled with a 6:3:1 ratio is 7x the ID but there are few of those sets used in every day rocket building nowadays because there are limits to the fuel used. While walking the safety beat at PGI, it appeared that a shorter spindle was being used, may have been around the Universal Hybrid size which is 4.35" vs 5.62". Whistle, strobe, hot BP, nozzled, nozzleless, color fuel etc. can all be used with the same tooling. And while there are those that have used the traditional tooling set for other rockets, that are by far the outliers and not the norm. Well.... Colored rockets with slow fuels are great candidates for the traditional BP tooling too. 1
sitas Posted October 1, 2016 Posted October 1, 2016 I'm very new here and don't know my way around yet. It seems as though I can not start a post, as it says to reply instead. Might have something to do with my newness here. Any way , I ve been reading all different areas and have noticed a few accidents. Being a total dummy here I have a couple of questions. I'm a bp shooter most of my life so I understand basic safety. I have been building potassium nitrate and powered sugar rockets, with a kitty litter nozzel and header. This is all drilled for a core and a passfire. I was ramming with an oak dowel.That worked fine in my testing. Then I read that I should make an aluminum ram,as it would compact even harder. It really does . What a difference. My biggest concern now is--Am I taking any risk by pounding this stuff tighter? Could it explode. If someone could help me I'd be real happy. If this post can't be here ,fine I guess .
BlueComet24 Posted October 1, 2016 Posted October 1, 2016 Sucrose and KNO3 fuel isn't going to go off from ramming. However, if you start using rocket tooling with a spindle, make sure your rammer doesn't hit the spindle. Also, be sure to drill slowly and by hand to avoid creating friction and thus heat. You can use Google to search APC (or any site) specifically, like this:site:amateurpyro.com
NeighborJ Posted October 1, 2016 Posted October 1, 2016 (edited) Sitas, I had the same problem when I first joined APC. I wanted to start a new topic but I couldn't figure out how. Once you make a post, like you've just done, the black "start new topic" icon will appear in the top right hand corner of each forum. For the question about the safety of hammering on Bp, it has been industry standard for century's to hammer bp for consolidation and it has a terrific safety record. However certain contaminants or foreign matter have contributed to some accidents but as long as your bp is of known quality there is very low risk of any ignition. From what I understand, the force needed to cause ignition would be far greater than one could generate with a hammer blow, baring the possibility of fuel getting punched inside the drift and against the spindle. Edited October 1, 2016 by NeighborJ
sitas Posted October 6, 2016 Posted October 6, 2016 Mister NeighborJ; great to hear from you . I'm an old fart looking for something to do along with my rc stuff. I really enjoy this because I'm making everything. One of the guys on here that had an accident is living within driving distance of me . I don't mind dying , but not at my own stupid doing, you know what I mean. I was really impressed in the difference between the metal aluminum ram and the wooden one . Those little motors flat out fly.They seem to love being made like a rock. I'm learning a lot just from lurking here. I could make most of the tooling I see here,but I want to learn more of the why fors first.I have a small basic metal and wood shop . Thanks again for the chat.
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