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Model Forum / General / Rockets / January 2006A newbie question . . . for the new path I am taking
Yup, I am new to what I plan to do, but I have played with rockets (pre-fab kits) that were just 'follow the instructions' and be a moron, but your rocket will fly. I want to get away from that. I plan on rolling my own rocket engines and using homemade black powder for the propellant. I will start small and make solid core engines. Cored engines will come later. The fuel is not a problem. I just need to know the theory and ratios to make a stick stabilized engine fly. You know, take engine, attach stick, light fuse, see rocket fly type of thing. I know the center of gravity should be above the center of thrust. So for a given size and weight of engine, how long should the stick be? I assume that the density of the stick has a factor in determining its length. There has to be a 'rule of thumb' to use as a guide. Hey, this is a first step, better rockets are in the future. Let me just get the engines right first. Please do not reply to this post with "glue part A to part B, then glue A+B to part C". What if I want to change a proven design by reducing it or making it bigger in size? Maybe I want to make a 1" rocket or make a 5' rocket. There must be something in common that applies to both sizes. Feel free to blast me if you want. I am sure that this information exists somewhere. Include a link with the reply perhaps? Tom the Canuck. > I want to get away from that. I plan on rolling my own rocket > engines and using homemade black powder for the propellant. >I just need to know the theory and ratios > to make a stick stabilized engine fly. You know, take engine, attach > stick, light fuse, see rocket fly type of thing. I know the center of Hi Tom, if you want to make BP stick rocekts that you lite with a fuse, you might try rec.pyrotechnics instead. most of r.m.r is factory built rocket engines. the skill here in r.m.r is in building the airframes, competition, scale, and science payloads. > > I want to get away from that. I plan on rolling my own rocket > > engines and using homemade black powder for the propellant. [quoted text clipped - 11 lines] > the skill here in r.m.r is in building the airframes, competition, scale, > and science payloads. Cranny Dane, I already read rec.pyrotechnics. Another interesting NG. There must be science, mathematics, and common sense behind the design of a new rocket. There are lots of things to consider, aerodynamics, drag, weight, stability, etc. I don't want to be spoon fed with kits. I want to start from scratch and do everything myself. If I can make my own equivalent of an Estes engine what would be the difference? Down to the ultimate question, home made or store bought, if they perform the same what's the difference? OK, r.m.r has the focus on airframes, scale and payloads. Can we not share some of that design methodology? Maybe in five years I will design a scientific payload that everybody might want to buy. Heck, 26 years of designing embedded systems and instrumentation and products can be used to do what I just mentioned above. I designed the hardware and wrote the firmware. I designed 911 systems. If you live in the US, your local PSAP probably has our equipment installed to serve you in case of an emergency. Does that qualify me to design the payload in the future? Look, all I asked was to get basic info to design a rocket. OK, the 'stick' rocket question was a starting point. Can I not start small and work my way up? Is that not the start of the path to learn more about rocketry when the goal is to do everything yourself? Ignorance can be bliss for some, but my mind keeps looking for new things to do and learn. Please help me follow my chosen path. All of you must have started somewhere to get to the point where you are now. Are you willing to share what you have learned with others? Simply, all I ask is knowledge, is that an evil in this NG? None of that 'buy this kit and build it', assembling pieces was learned when we were young and had a set of blocks. Designing the set of blocks is my goal, get the analogy. Oh, I forgot to mention this, 1/4watt 10ohm metal film resistors when connected to a battery of 12VDC with 1Ah capacity tend to smoke, turn red, and burst into flame. And they are cheap, $0.005 each in large volumes. But then again you could use a strand of wire from a pad of steel wool with maybe a dab of BP and dextrin added to coat the steel wool. Why buy when you can make your own for less. There you go, electric ignition, no fuse lighting, are you happy now? (let's not forget the relay to minimize the IR drop of the wire to launch the rocket. Use 16AWG to wire the relay to the battery and igniter. Use 22AWG wire to operate the relay. As Homer Simpson says "Duh!") Tom the Canuck. Unless the rocketeer has started with model rockets and followed the safty code and worked their way up into the high power rocket range, those of us who still fly model rockets still use the factory made engines and/or reloads. and still follow the safty code.  SignatureThe Lone Sidewalk Astronomer of Rosamond Telescope Buyers FAQ http://home.inreach.com/starlord Astronomy Net Online Gift Shop http://www.cafepress.com/astronomy_net In Garden Online Gift Shop http://www.cafepress.com/ingarden Blast Off Online Gift Shop http://www.cafepress.com/starlords >> > I want to get away from that. I plan on rolling my own rocket >> > engines and using homemade black powder for the propellant. [quoted text clipped - 64 lines] > > Tom the Canuck. > I already read rec.pyrotechnics. Another interesting NG. There must > be science, mathematics, and common sense behind the design of a new > rocket. There are lots of things to consider, aerodynamics, drag, > weight, stability, etc. I don't want to be spoon fed with kits. I > want to start from scratch and do everything myself. http://www.apogeerockets.com/rocksim.asp > If I can make my own equivalent of an Estes engine what would be the > difference? Down to the ultimate question, home made or store bought, > if they perform the same what's the difference? http://www.apogeerockets.com/education/downloads/Newsletter135.pdf Scott Bryce wrote : > > I already read rec.pyrotechnics. Another interesting NG. There must > > be science, mathematics, and common sense behind the design of a new [quoted text clipped - 9 lines] > > http://www.apogeerockets.com/education/downloads/Newsletter135.pdf Scott, Thanks for the links. NASA provides the equivalent of rocksim for free. Not as nice looking but it works. http://exploration.grc.nasa.gov/education/rocket/bgmr.html How come Newsletter135.pdf tries to talk you out of making your own rocket motors? They portray making your own as dangerous and a cause of death. What's going on here? Do they just want you to buy their product instead of making your own? I have been making BP for years and still have all my body parts. Know what you are doing and follow standard safety precautions. Standard BP is safe (avoid flame or spark). Potassium chlorate and sulfur can be dangerous. Just put a SMALL amount of sulfur on your driveway and add a SMALL amount of potassium chlorate on top. Rub with hammer at arm's length. Wait a bit and the ringing in your ears will go away after the explosion. Read rec.pyrotechnics for more fun stuff. Let me put it this way. I am not stupid, I learn all I can before I even try. I evaluate the risks involved and plan the course of action based on that. Why do you think I posted here to start with? Why, to get more info before I do something. I e-mailed Estes and asked what they use for their motors. I think it is BP, maybe the classic 75:15:10 mix or a variant. Heck, I can make my own and not kill myself. If I wanted to live dangerously, I would make a BIG batch of this: The mix was Armstrong's Mixture, 67% KClO3, 27% red phosphorus, 3% sulfur, 3% CaCO3 dissolved in water with some gum arabic or similar binder. <<<DANGER>>> Tom the Canuck. > Cranny Dane, > I already read rec.pyrotechnics. Another interesting NG. > There must be science, mathematics, and common sense > behind the design of a new rocket. There are lots of things > to consider, aerodynamics, drag, weight, stability, etc. Hello Tom, Not much if you just want to fly it on a stick. Most Pyro rocket designs will fly just fine on a stick with a fuse for ignition as you stated in your first post. skyrocket motor designs abound on rec.pyro style information sources > OK, r.m.r has the focus on airframes, scale and payloads. > Can we not share some of that design methodology? You mentioned you watned to know how to make BP motors. Sleeters book will tell you much info on that. I see others posted to it. If you want to fly something more then a stick we will be glad to give you great advice. > Look, all I asked was to get basic info to design a rocket. > OK, the 'stick' rocket question was a starting point. Can > I not start small and work my way up? If making BP motors, I'd test them in the ground before using a stick. then I'd put them in simple skyrocktes rather then a stick. Later, with working ejection charges, model rockets would be a step to work up to. > Oh, I forgot to mention this, 1/4watt 10ohm metal film resistors > when connected to a battery of 12VDC with 1Ah capacity tend to > smoke, turn red, and burst into flame. And they are cheap, $0.005 > each in large volumes. But then again you could use a strand of Yes that is true, a hybrid manufacture uses them for igniters, but he had to go with 24 volts to make them reliable. That's easy. Go get a copy of Stine's "Handbook of Model Rocketry". ISBN: 0471472425 Read the section about stability. I'm not sure that he talks about stick rockets, per se. But he starts by talking about the stability of a stick, then goes from there. Lots of morons learned stability using those pre-fab kits. They are a lot more sophisticated than a stick rocket. > Yup, I am new to what I plan to do, but I have played with > rockets (pre-fab kits) that were just 'follow the instructions' [quoted text clipped - 28 lines] > > Tom the Canuck. > That's easy. > Go get a copy of Stine's "Handbook of Model Rocketry". ISBN: 0471472425 [quoted text clipped - 3 lines] > Lots of morons learned stability using those pre-fab kits. > They are a lot more sophisticated than a stick rocket. <snip> Agreed. But I am not a moron, although there seems to be a surplus of them living on this planet. Heck, some even appear to have government positions and titles. My post was just a stab in the dark to get some info. Is there another NG that would be better? I agree, getting a book is a good idea. Google might help as well since you guys have yet to provide any real info. Who knows, maybe in ten years I will launch a SCUD missile from my backyard. (Joke, I would never do it.) Tom the Canuck. And something for this NG to enjoy or comment on: (credit to lightnpyro@yahoo.com for the original post) >> A major research institution (MRI) has recently announced the >> discovery of the heaviest chemical element yet known to science. The [quoted text clipped - 19 lines] >> quantity in concentration. This hypothetical quantity is referred to as >> Critical Morass. > My post was just a stab > in the dark to get some info. Is there another NG that would be > better? I agree, getting a book is a good idea. David Sleeter book "Amateur Rocket Motor Construction" or something like that is a great book if you want to make black powder motors. You can get it on Ebay. However most of his motor designs are core designs. He includes propellant formulas. He barely touched on end burners like the Estes motors. But I did my own experimentation and have matched and even exceeded Estes on end burner black powder motors and it was very fun doing it. I even kept the overall dimensions identical to Esters so that I could fly my homemade motors in my existing rockets. Good luck KT I want to grow my own balsa, make my own cardboard and form it into tubes, and formulate my own glue and paint. > I want to grow my own balsa, make my own cardboard and form it into > tubes, and formulate my own glue and paint. Sorry I even gave some advice here next time I see your name I'll just delete it. The problem with Tom was that he *started* by throwing an attitude around, implying only "morons" build kits and fly premanufactured motors. I tried giving some honest advice (admittedly from a model rocket perspective -- I was also going to recommend Sleeter's book but couldn't remember his name) and tried to let him know the attitude wasn't appreciated and Tom just threw attitude back at me. Jim was just parodying Tom's attitude. "if I didn't make it myself or get it for free it ain't worth [crap]" Roy nar12605 >> I want to grow my own balsa, make my own cardboard and form it into >> tubes, and formulate my own glue and paint. > > Sorry I even gave some advice here next time I see your name I'll just > delete it. > The problem with Tom was that he *started* by throwing an attitude around, > [quoted text clipped - 8 lines] > it > for free it ain't worth [crap]" My mistake, I thought it was Tom who had made the make your own glue and grow your own balsa comment. Now I understand the joke. Just thought Tom was being rude to me but it was just Jim having fun. All is forgiven. KT Kimball- Thank you for the tips on tube rolling, those will come in handy, indeed. As for the issue of "Tom the Canuck", a little word of advice; "Most a.sholes are born that way, they seldom ever change. However, if they do, you will find it is seldom for the better". First off, his condescending attitude towards all in this group is quite agitating. He seems to be casting the impression to all that he has somehow lowered himself to approach this group to find answers to his questions or to seek validation for what he thinks he already knows. thanks again for the tips, Bob352 > Sorry I even gave some advice here next time I see your > name I'll just delete it. You made a good post on rolling your own tubes. Keep it up. Jim was just having a little fun. Doug > I want to grow my own balsa, make my own cardboard and form it into > tubes, and formulate my own glue and paint. :) SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com LOL. Sounds like this will keep you busy for many years. With all that work you wrote about, I don't think that you will find the time to post here again for a long time. I like the stuff you are made of if you are going to get down to the very basics of doing it all yourself from scratch. Good luck with your 'project'. Post back in a few years and let everbody know how well you did. Tom the Canuck. > I want to grow my own balsa, make my own cardboard and form it into > tubes, and formulate my own glue and paint. I would guess that making your own glue would be about as difficult as making your own fuel. But I have never heard anyone anounce that they are new rocketry and are going to make their own glue. On the other hand, I have lost track of the newbies who proudly annouince that they are going to make there own fuel. (And it is almost always a newcommer.) What is so fascinating about making your own fuel? There are so many othe interesting things ro do in rocketry. Making your own fuel has its place in rocketry, but it is an advanced topic and even then not for everyone. Slow down, sit back and enjoy the trip. > I would guess that making your own glue would be about as difficult as > making your own fuel. But I have never heard anyone anounce that they > are new rocketry and are going to make their own glue. www.make-stuff.com/formulas/glue.html > Agreed. But I am not a moron, although there seems to be a > surplus of them living on this planet. This should be in the FAQ. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com > I want to get away from that. I plan on rolling my own rocket > engines and using homemade black powder for the propellant. > I will start small and make solid core engines. If you roll your own engines I suggest you use Gorilla Glue (Elmer's Polyurethane). It expands and makes a beautiful tube for both engine and for Airframe. You have to put a turn of wax paper over your mandrel and then a turn of Saran wrap over the wax paper. Then squeegee the Gorilla Glue over your paper so it wets the paper. Keep it thin. Roll the paper around the mandrel tight. Then roll saran wrap over the finished product keeping it tight and wrinkle free. Then wrap it with shrink tape in a spiral like the spiral wrapped body tubes you buy. Use a heat gun to shrink the tape. Let it dry over night and you will have a very strong and beautiful tube. Sand the OD to get rid of the rough finish. If you don't have shrink tape just use packaging tape (not duct tape unless you want the tape pattern in the finished product). Wrap the packaging tape in a spiral around the rolled tube as tight as you can get it being careful not to get wrinkles in it. The glue expands and will fill in any wrinkles leaving a bump. Not using shrink wrap is ok because as I mentioned the glue expands to 4 times the original size as it cures. It will still make a good tube. These tubes are much better than the paper body tubes you buy from Estes or other hobby outfits. And it gives one much more satisfaction having made them yourself. KT |
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