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Rocket Guidance Ideas Wanted

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Author	Topic: Rocket Guidance Ideas Wanted
BaDSeeD Frequent Poster	posted January 25, 2000 05:29 PM Ok guys i know my posts can get long... so i'll try to make this one more brief. I'm looking for ideas to keep heavy explosive rockets traveling straight. I have tried a few different ideas, but am not satisfied with the results as i would like to have a supply of rockets ready. My first attempt Was to make spring loaded folding fins. Now .. i'll admit.. these worked GREAT so long as the fins were alligned properly. But there was just WAY too much work into each rocket. I tried a set of tassles on the end of each rocket for some resistance to keep it going straight, but it slowed down the rocket too much, and couldnt be used with a rocket engine.. had to be used more like a mortar. The idea i have been working on now is a rifled barrel.. hoping that the spin will be sufficient that i don't need fins. Now i have already made the broach i need to cut the rifling, but i've found out that the pvc i intended to use for the rocket bodies.. varies so much in size... that it couldnt be used that way. Hell a lot of the stuff isnt even round. I dont want to have to harden the barrel of my launcher.. cause it may warp.. so i cant use steel for the rocket bodies. And other metals will again be too much work. Does anyone know how consistent SC80 is? How well it holds its size and cylendricity? And if anyone else has any ideas for guidance to keep these rockets flying straight.. please post them. ------------------ Knowledge is the true power, ignorance will bring your demise.
m3nth Frequent Poster	posted January 25, 2000 07:27 PM how about a gyroscope? i am not sure exactly of your application or how big the rocket is or even how easy it would be to make a gyroscope that would work but it doesn't seem like it would be too hard. you would have to have a stationary case that could be mounted inside the rocket and then a spinning weight inside of that run by a small dc motor operated on a set of batteries. weight would be minimal as would cost, a few dollars maybe. hardest part would probably be making the thing spin inside something you could mount to the rocket. just an idea though. ~m3nth~
Ho ju Moderator	posted January 25, 2000 08:21 PM that would be a little expensive though and tedios if you were to use to use it for every rocket that you made. ------------------ http://members.xoom.com/Splynncryth [This message has been edited by Ho ju (edited January 25, 2000).]
VeHeMT Frequent Poster	posted January 25, 2000 09:09 PM What about an angled exhaust port on the exterior of the motor so that when the rocket launches it also has gas moving out the side of the rocket making it turn. Here is a web page that takls about Stinger missiles (a spin stabilized rockets commonly used in pyrotechnics). The page will show what kind of hole im talking about. http://www.ctel.net/~dwilliams/stinger/stinger.html BTW this is the type of guidance the Germans used in WWII to make their fin-less rockets go straight. ------------------ VeHeMT's Armoury
BaDSeeD Frequent Poster	posted January 25, 2000 09:27 PM lol If i was making a cruise missile, i might use gyroscopes, but these are small rockets, the body diameter is to be LESS than 2 inches in diameter. I'd rather they were between 1 and 2 inches actually. Another project i intend to make them 4 inches.. but thats another story all together. I thought about an angled secondary exhaust.. but worry that it'll make it more unstable. And loose much of the velocity. I'm only looking for a direct fire weapon, with a max range around 100 yards. ------------------ Knowledge is the true power, ignorance will bring your demise.
HMTD Factory Frequent Poster	posted January 25, 2000 11:41 PM You want the rocket to fly without vertical drop or free of biasing? What do you use to make the fin?
m3nth Frequent Poster	posted January 26, 2000 10:36 AM ah yes... a gyroscope would be highly impractical for your application i was thinking a big four foot tall sucker to launch halfway across the city at your local irs headquarters are you making your own rocket (like the fuel part) or what are you using? i have a friend interested in refilling some old estes rockets but am not sure where to start out. these rockets you are making sound like maybe bazooka rockets where you would put some kind of explosive to go off on impact or with a time delay... is this correct or am i way off again? for size anyway they sound small enough to be shoulder launched out of a pvc pipe. ~m3nth~
BaDSeeD Frequent Poster	posted January 26, 2000 02:35 PM Yeah exactly. I plan it to be a shoulder launched rocket. And yeah explosive too. I am also taking ideas on what explosives i should use.. for the main charge, and what to detonate it with. First problem is just to get some consistency with the rockets... thats why i havnt even mentioned the explosives yet. I'd prefer impact detonation too. Although an adjustable time delay would be pretty good if i were to use them for an anti aircraft purpose. I think i am going with the riffled barrel too. I have already started building my "other" launcher. This one is BIG. It's tripod mounted, electrically fired, and has a rocket body that is 4 inches. These arnt pvc. They are hot rolled steel, and .250 thick (walls) i have pre scored the body for shrapnel, and have only to load them. This one i am making some special purpose rounds for. I plan to make some anti personel missiles (warhead of about 300 1/2 inch steel ball bearings) a napalm load with a timed detonation to blow BEFORE it hits ground to scatter the napalm, obviously impact detonated HE rockets, and i'm working on another round to use. I want a direct fire anti personel round. Since my launcher is a breech loader (with a locking breech) i think it should withstand the pressure of a blast for this. Basically .. i have started making sabots out of pvc, and loaded them with ... ohh hell.. there's several hundered flechettes in each one (i didnt count..just weighed them). This load will be similar to a shotgun patern.. for distances too close to use a rocket. Lots of testing with this before i try to fire one. So far i havnt even put sights one this yet.. not sure what i want exactly. They deffinatly have to be adjustable for the different rounds. So there's the dilema Also this thing isnt as portable as i'd have liked... so far.. it already weighs 230 pounds. Thats the launcher and tripod together. I'll post more on this.. maybe some pics too as i get closer to finishing it. ------------------ Knowledge is the true power, ignorance will bring your demise.
roger25 A New Voice	posted January 26, 2000 05:50 PM I was thinking about rockets that would detect human heat. I came up with the idea of vector thrusted exhaust (use small electromagnets to decline exhaust). Also, if you make a search on "thermopile detectors" on the internet, you'll find appropriate sensors that detect human radiation. They have a size of transistor, but f...ng expensive ($100-150 per sensor). In order to follow a human you would need at least four sensors. That all along with the small curcuit (two op-amps will do it) will perfectly fit into the rocket 1" in diameter. You can try http://www.calsensors.com/ for termopiles... Good luck
catch22 Frequent Poster	posted January 27, 2000 12:10 AM BaDSeed, From your first post it sounds like your rockets just fine but the motor is too small if you use a larger motor the weight of the payload will have much less effect on the trajectory of the rocket. What are you currently using as your motor? Contact me if you would like a diagram of an excellent pvc motor that can be adapted to almost any sized pipe for different thrust capabilities. If you have acess to a wood lathe and a drill press you can make very repeatable rocket motors. As for the explosive I would suggest Nitrocellulose colloidined with acetone and added to 3/4 it's weight of ammonium nitrate. Use a blasting cap with an RDX booster to detonate the mix. To set off the blasting cap you could use a simple "normally open" electric circuit with a momentary switch mounted on the tip of the nose cone. Catch22
BaDSeeD Frequent Poster	posted January 27, 2000 03:23 PM Catch22 That is similar to the idea i have for a detonation type.. albeit the explosive is different. I want a round that can be stored safely.. so i plan on having removable detonators, or at LEAST a removable arming pin. As for the engine. I have used two parts pyrodex, to one part smokeless, gelled and hardened into a single grain with acetone. I am open to new ideas... cause i havnt tried an engine like that with such a heavy rocket. And yes.. i have access to .. well hell anything. I can litterally build anything i can come up with. I'm leadman, and Prototype engineer for a large machining company here in N.Y. Since i do much of my work without the bosses even knowing, no one questions what i am doing when its a personal project. ------------------ Knowledge is the true power, ignorance will bring your demise.
vos A New Voice	posted January 27, 2000 07:46 PM I used to play around with making rockets, but havent gotten around to those sorts...but Ive been playing with the thought that you could use some cruise missle design on a smaller scale, namely, the wings. Its not hard to build them in-body(rubber bands open them, and a small v-catch keeps them open). You'll probably need stabilizers still, but its easier than rifling. Wings need to be forward and a small weight in back to balance things...But that should provide a nice level flight with a little design tweaking.
catch22 Frequent Poster	posted January 28, 2000 02:55 AM badseed, Pyrodex is a waiste of money, and as far as rocket propellant goes so is smokeless. A far superior rocket propellant is 70% potassium nitrate and 30% powdered sugar, melt them together and cast into the case. Write me and I will send you detailed instructions on how to make some excellent motors. ------------------
BaDSeeD Frequent Poster	posted January 28, 2000 05:19 PM Pyrodex and smokeless may not be the best choice for rocket motors, but i always have both of them on hand. I reload often, and have a couple muzzle loaders that i use (during the right season). I've heard aboutt hat potassium nitrate mixture. But havn't done any serious looking for the supplies. Where can i get quantities of potassium nitrate without having the FBI pay me a visit? ------------------ Knowledge is the true power, ignorance will bring your demise.
VeHeMT Frequent Poster	posted January 28, 2000 06:54 PM KNO3 isnt a watched substance(correct me if I'm wrong). It can be had as fertilizer. Vicksburg sells it under the name KPOWER.
catch22 Frequent Poster	posted January 29, 2000 02:51 PM Very close VeHeMt, ammonium nitrate is a controlled substance, potassium nitrate is not. It doesn't look good to be buying a lot at one time but very few people that work in places like garden stores that sell it know what it is or what its used for other than gardening purposes. BadSeed, you can get Potassium Nitrate (KNO3) from Skylighter for very cheap, or Pyrotek, or Iowa pyro supply, or fire fox, or hell as already stated you can even get it at a garden store. Catch 22
VeHeMT Frequent Poster	posted January 29, 2000 03:21 PM I said isnt, not is. And my suggestion was to get it under the pretense of fertilizer. Thats what the Vicksburg chemical company does. They sell it as K-Power. It even says KNO3 on the sack.
catch22 Frequent Poster	posted January 31, 2000 02:28 PM BadSeed, I was going over your post and came to a realization. You said your rockets were fired out of a breach loaded tube with a locking breach. Well if you left the breach open it would function better. If you look at RPGs the breach of the tube is left open. The reason for this is that it allows the rocket to reach a high enough thrust to propell itself. If the breach is closed hell the pressures from a large enough ignitor would push it out of the tube, and the rocket not being at a sufficient thrust would succome to gravity and its trajectory would be drastically compramised. Try a few rounds with the breach open. Im absoloutly positive this will improve your results if not greatly at least a little. Catch
BaDSeeD Frequent Poster	posted January 31, 2000 11:26 PM Read the post. That was for another project, that uses DIRECT FIRE rounds. Like beefed up shotgun shells. Its a cannon, not an rpg. ------------------ Knowledge is the true power, ignorance will bring your demise.
West Frequent Poster	posted February 04, 2000 04:27 AM catch 22: I think the PRIME reason for not using a closed breach is that the recoil would take your shoulder off... cool you seem pretty anti nitrocellulose in regards to rockets, what do you think of the propellant off makeshift arsenal comprising of nitro cellulose & blackpowder. . it seems to me that if it burns fast enough it should perform better than either strait blackpowder or kno3/sugar ..
Zanx Frequent Poster	posted February 04, 2000 10:02 AM Catch22, could you post your detailed instructions on making PVC rocket motors using the KNO3/sugar propellant here? If not, could you email them to me? Thank you. [This message has been edited by Zanx (edited February 04, 2000).]
VeHeMT Frequent Poster	posted February 04, 2000 06:32 PM The truth is that NC doesnt work well for small rocket motors. And like you said the propellant in the makeshift ARSENAL is also comprised with BP. Alone the NC wont burn fast enough or create enough pressure for a small motor. But, like you said, with the BP it sufficiently increases the burn rate so that it can be sued practically. ------------------ VeHeMT's Armoury

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