AirCowPeacock Posted November 1, 2012 Posted November 1, 2012 Maybe this would make an okay colored rocket fuel. KClO4 25%Sr(NO3)2 / Ba(NO3)2 40%Sucrose 20%Al 5%Parlon 10% Milling the Sr(NO3)2 / Ba(NO3)2, Parlon and Sucrose together for a few hours, then screening in the KClO4 and Al.
usapyro Posted November 1, 2012 Author Posted November 1, 2012 (edited) Sugar doesn't ruin the color? Where did you find that comp? A green rocket fuel, now that would be interesting... Btw, I got some engines done with the low offset and perfectly rounded choke on the internal nozzle. Lets see if the charcoal can make it past that choke tonight! Edited November 1, 2012 by usapyro
AirCowPeacock Posted November 1, 2012 Posted November 1, 2012 I didnt find it. I just made it up now. Would sugar ruin the color? Ive gotten good blues and yellows with sugar fueled comps. Just for fun of course--too hydrogscopic for stars or fountains. Oh and purples
usapyro Posted November 1, 2012 Author Posted November 1, 2012 (edited) Ah, ill go out and test it and see what I think. Here is the updated design for tooling.The changes... This design only needs a very small offset. The side of each vent nozzle can be drilled with it's edge touching the center point. The internal choke needs a nice rounded slope to make it easy for the charcoal sparks to reach the nozzle, either that or a longer low angle slope, but that causes more weight in clay. Once the sparks start reaching toward the channel in the choke the pulling force of the gas is stronger so a steeper slope is fine there. If this works perfectly and doesn't trap sparks it's my last test and I'm done with these for this year, otherwise I will do one more run of tests with flaps/propellers to slow rotation down.http://i45.tinypic.com/123385e.jpg Edited November 1, 2012 by usapyro
AirCowPeacock Posted November 1, 2012 Posted November 1, 2012 How do you figure propellers will effect the post burnout flight?
usapyro Posted November 1, 2012 Author Posted November 1, 2012 (edited) I don't think it will make any difference. During flight it will provide more lift if your angle on the propeller is correct. If you don't put a report in, the thing will float downward like a propeller on a stick. Especially if you use a big propeller! I think I have some old model aircraft propellers lying around somewhere... Might be interesting to launch one without hardly any downward trust just using high offset and a propeller. You can make propellers easy by soaking certain types of wood in water, heating them, and twisting them... Then leaving to dry. Anyone happen to know if pine wood works good for that? I have lots of very lightweight pine I can machine and plane to a specific thickness. I'm thinking more along the lines of creating a proper decent performance propeller that has a changing twist to it. Edited November 1, 2012 by usapyro
AirCowPeacock Posted November 2, 2012 Posted November 2, 2012 Sounds like a great idea. But I do want to put a salute on it. But I might have a better idea. Light the salute with a 'waterfall' as it floats down and eject it so it bangs then has a beautiful falling waterfall. Might be a bit--crazy--though. I would need the waterfall to produce very little thrust though. But if it produced just enough I could slow the descent.
usapyro Posted November 2, 2012 Author Posted November 2, 2012 (edited) Latest rounds of testing. These are using 50:50 BP/SF + 7% pine charcoal (airfloat) + 7% pine charcoal (rough, blended). Reports were only 1g case shredders. Forgot to include the fast fuel increment on launch... Required for a straight launch with that launch setup. I went back to a tube launcher because I broke my other one. (Hot glue didn't hold, lol....) Definitely not nearly as good. I will make a new launcher out of guide sticks again! I need about a foot and a half long launch guide and I think I can actually launch that slow reliably... Need to put a plum bob on it to make it perfectly level. No, those were not propellers... Those were angled flaps to keep the rotation speed down. I kinda overdid it... Haha...http://www.youtube.com/watch?v=J7N_c-Yo89U One thing I love about these...http://i47.tinypic.com/b9hpft.jpgThe firework is completely obscured! And this made me think... What would a green Bengal comet (real slow color comp) burning on the bottom look like? I think it would light up the smoke and reflect off the sparks and might look pretty neat! I have decided the amount of sparks being produced is plenty with the low offset and rounded choke. I kinda like that it's trapping some sparks. I am going to put in very thin 2mm thick increments of black powder to spike the pressure and release spark rings during flight. Going to be a never before seen simple effect! No, I didn't intentionally create those spark rings in the first rocket. Those were caused by inconsistencies in my rammed increment burn causing pressure fluctuations which forced the sparks out. Edited November 2, 2012 by usapyro
usapyro Posted November 2, 2012 Author Posted November 2, 2012 (edited) New launch platform plan... I should be able to launch so slow that the the firework won't lift off until some of the fuel weight is burned off, and still get a perfectly straight up flight... Hehe... I think ill make the guide rods a foot and a half this time.http://i49.tinypic.com/303i78i.jpg Here is my previous one that worked perfectly... But broke... Stupid weak hot glue!http://i50.tinypic.com/vymuj4.jpg Curious how I got the guide rods so precise? I just took the pieces of wood and attached them to a pipe with a rubber band. After they were glued down I removed the rubber bands! Viola, perfect launching guide! Edit, actually... Omg! Even better design... Simpler and easier to make...http://i45.tinypic.com/141s1ht.jpgThe firework is rested on a rounded dowel. My bulkheads are already shaped like this which is a plus. This will allow it to start spinning easier even before launch! More stability!!! Edited November 2, 2012 by usapyro
dagabu Posted November 2, 2012 Posted November 2, 2012 You are doing fantastic work here, keep it up please. I just love a new design that works!!! -dag
usapyro Posted November 2, 2012 Author Posted November 2, 2012 (edited) Thanks. I just love the slow takeoff with six seconds of flight time... Out of a 2.5" effective fuel grain... Haha... Total length of these is only 4.25". If you bumped it up to 6.5" with a slightly more powerful fuel(+6% charcoal only) you could get around ten seconds of flight time! Launch multiple at a time... I may be able to finally get the stable hovering launch I always wanted!!! Long time goal... Updated Optimized Version... Because of the V shape to the back of the internal nozzle/choke it is almost as strong as a rocket nozzle. It is unnecessary to have more than 3mm of clay back there from the tip of the internal nozzle to the very back. Around 4-5mm is optimal for a 1" I.D. to insure against any blowouts, but I have no problems with 3mm. Make sure the clay back there is rammed or pressed until glossy and shiny. Kitty litter rules! This helps reduce weight in clay. Also... I don't launch these with very high pressure because I'm going for long flight time. http://i45.tinypic.com/25tuqnt.jpg Edited November 2, 2012 by usapyro
dagabu Posted November 2, 2012 Posted November 2, 2012 Keep working on these, I would love to do a broad front at PGI with these some day if you can get that super slow rise and long burn times. -dag
usapyro Posted November 2, 2012 Author Posted November 2, 2012 (edited) This is the ultimate design right here... Needs some good tooling! http://i47.tinypic.com/zsn2ae.jpg This thing really needs that long low angle choke to keep the Rough Charcoal/FeTi/etc moving toward the nozzles smoothly. I would recommend using a 10-15% wax bentonite clay for the internal choke to insure against cracking. You want that thin edge from the casing into the choke to hold like that so that the sparks can bounce along smoothly. Now this tooling I will have to get some of if anyone makes it! There won't be hardly any centrifuge issues with this! Edited November 2, 2012 by usapyro
dagabu Posted November 2, 2012 Posted November 2, 2012 I wish I was able to turn them for you (and a set for me too) but I am still three weeks out... I would use a slit block of plastic with a cam or bolt to cinch it down on the tube with the holes drilled into it for the nozzles and press in a couple of drill guides (spring pins) to keep the alignment perfect each time. The rammers are easy-peasy, one with the same point you show in your drawing and another one that is flat. -dag
Algenco Posted November 2, 2012 Posted November 2, 2012 nice, now that's how to direct that desire to find a better way.Keep up the good work
FrankRizzo Posted November 3, 2012 Posted November 3, 2012 That's super cool, usapyro!! A design that Lloyd Sponenburgh has often touted for a similar effect, is to take a short, cored rocket engine with a nozzle, and simply light it from a hole drilled in the side of the tube while it's lying on the ground like a normal spinner. The brief bit of spining on the ground helps establish some gyroscopic procession, then when the flamefront hits the core, the device rights itself and shoots straight up. That cored burning allows for a tamer fuel to be used for the spark ejection.
usapyro Posted November 3, 2012 Author Posted November 3, 2012 (edited) LoL... That sounds a littler hazardous Frank... How exactly does the forward thrust make it automatically point straight up? I would imagine it would look something kinda like this...http://www.amateurpy...design-w-video/ Btw, here is my new launch pad. I should be able to do straight up near levitation slow launches now.http://www.youtube.com/watch?v=T_OyhGq3sGs All cedar except for the treated wood base. Those guide rods go down half way through the base. There is 2mm extra free space on all sides for the firework. The aluminum around the guide rods prevents them from being burned by exhaust and lowers friction in that area. I was going to keep things simple then I kinda went overboard once I got my hands on the wood! Edited November 3, 2012 by usapyro
FrankRizzo Posted November 3, 2012 Posted November 3, 2012 (edited) LoL... That sounds a littler hazardous Frank... How exactly does the forward thrust make it automatically point straight up? You have to think about how the thrust is applied. After it's began rotating, the thrust coming from the nozzle will be trying to push it sideways, but as it rotates, "sideways" (edit: "straight ahead" is a better description) isn't possible because the thrust is being applied in toward the center of rotation. It also can't go toward the ground because it's solid and resists that. The net result is that the the only direction the motor can go is straight up. :-) It's probably important to use a really hot powder near the nozzle (where the rotation vent is driled), in order to get enough spinning energy stored to resist an errant trajectory before the core ignites. Edited November 3, 2012 by FrankRizzo
usapyro Posted November 3, 2012 Author Posted November 3, 2012 (edited) I may need to read up on gyroscopic effects a little more... These flying fountains even when spinning at insane speeds... They can change angles slowly if launched with a tilt. It would be great if they could only go straight up or straight down. These FF's only seem to change angle at the same rate of change that was established at launch... So if you get a straight up stable launch, they stay straight up. If they are starting to tilt at the start... They continue to change by the same amount of tilt over the same amount of time. When they get rotating fast parts of their motion are locked... Like the direction they are tilted never changes. For example... A couple seconds after launch. If the firework is tilting a few more degrees per second... It will continue to tilt a few more degree per second through it's entire flight, but it never changes the direction of the tilt in unless there is wind or a tree branch. With my new launcher if I am lucky... Enough rotation will be established to lock in trajectory with only a few degrees margin of error before it leaves the guide rods. Edited November 3, 2012 by usapyro
usapyro Posted November 3, 2012 Author Posted November 3, 2012 (edited) Oh, I just figured out how fins should be done to make launches off of concrete reliable... Fins are more for stabilization than rotation. Edit: Note, remember to angle your fins the same way as your offset creates rotation... http://i48.tinypic.com/w22gsh.jpg Btw, has anyone here ever managed to get a straight finned rocket to launch off of concrete without a guide rod? I have not even been able to launch estes rockets without guide rods... God damn... Nothing like being chased around by a random estes rocket that I thought would fly straight without a launch pad... AIEEE!!! Edited November 3, 2012 by usapyro
AirCowPeacock Posted November 3, 2012 Posted November 3, 2012 It would look cool to launch a model rocket without a guide, but its simply not going to happen (atleast not without a mechanical gyroscopic system,) and I imagaine could be very dangerous! I think FrankRizzo is talking about a stinger. Just doesnt know the name. Correct me if I'm wrong. Have you tried the fins yet?
dagabu Posted November 3, 2012 Posted November 3, 2012 (edited) Sure, but you have to have pretty large fins and they have to overhang the end of the rocket by a couple inches or the initial thrust throws it on its side. They sell a few modern versions in the C class tents. http://media.merchantcircle.com/30001546/12__Warhawk_Miss_485c2ce87e8df_full.jpeg -dag Edited November 3, 2012 by dagabu
usapyro Posted November 3, 2012 Author Posted November 3, 2012 So, as I figured... To get a rocket with fins to work straight off the ground you need to bring the center of gravity down to the engine or lower just like with stick stabilized rockets... Grrr... Not liking these slow launches with this new launcher... Not as accurate as my original method!
usapyro Posted November 3, 2012 Author Posted November 3, 2012 (edited) Screw complex launchers, going back to my original technique for launching these flying fountains... You can just set the things on pavement and launch them if the increments are done like this... Provided your delay comp doesn't tip it over! A three inch guide tube or guide rods are recommended. Just put a delay comp in... Then let it rip with a fast fuel to take off quick and straight!!! Simple and reliable...http://i50.tinypic.com/2eg9n40.jpgThose slow takeoffs just don't work well... Fast launch is the only way to go with these! I am going to attempt a hover with a different design... If someone else solves how to do a slow nearly hovering launch be sure to post! Kicking off the ground fast first and then slowing down is the only thing that seems to work when it comes to getting a straight up trajectory with a slow flight. Ok, I'm done with these guys... I think the design is as good as it's going to get!!! Working on something new now. Have fun!!! I will just provide one more video. One with bottom angled fins launching off pavement with no guidance as seen in post #70. I think the official name should be something like Canister Rocket! The things are shaped like a canister... You can launch them out mortar tubes and do all sorts of stuff with them! Er, when I said launch out of mortar tubes... I did mean with lift! Just blackmatch the vent nozzles. Edited November 3, 2012 by usapyro
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