kwstag Posted April 27, 2006 Posted April 27, 2006 Small KNO3/Sucrose rockets are easy to fly with no core.. As tekxnix said, like bottle rockets basically.. But for larger ones, cores are still extremely easy to make.. I don't think anyone posted pictures or videos of any so I'll dig some of mine out and post them.
rocket Posted April 28, 2006 Posted April 28, 2006 How long should the stick be on one of these rocket is it the same rule as BP rockets?
Caleb51 Posted April 28, 2006 Posted April 28, 2006 Yes. You should be able to balance the rocket (with stick attached) just behind the actual rocket.
Spoony Posted April 28, 2006 Posted April 28, 2006 Man, I just made some recrystallised KNO3/Sugar using the toaster oven method from www.jamesyawn.com and it is much better than the normal KNO3/Sugar. I am never going back!
teknix Posted April 28, 2006 Posted April 28, 2006 I just use dry packed KNSU. It beats having to mess with the melted stuff and works just as good. Melted KNSU is always a mess and is more work than is nessicary. I can make a rocket from start to finish and ready to launch in less than 5 min with this method. I have the method well outlined in this book: http://www.freepgs.com/pyroteknix/Easy_PVC_Rockets.pdf
chappers Posted April 28, 2006 Posted April 28, 2006 that may be ok for the small engines you describe in your pages but for larger engines, that is simply not the case and a melted and poured or re-crystallized method is the only practical method.Indeed the larger the motor the more towards a pure melted method you are looking at. Also to be taken into consideration is the amount of air entrapped in he motor and the dry methods you describe entrapp more air than the other methods and this in its self can cause over pressurisation and CATO situations.I am currently testing a 9" by 1.75" motor and from past experience of dry rammed motors wouldn't even entertain the possibilities, due to the efforts necessary to ensure good solidification/ packing)Teknix although there is some useful information on your pages I feel the data is limited to the smaller sized engines you describe and should not necessarily be scaled up to larger devices since the deviations from the pure thrust curves you have shown can cause unexpected results.in summary i would say that each method has its uses and should not just be blindly be scaled up because "it worked last time" there is atime and place for each type of fuel and the fun is finding out for your self safely.
mr.pyro Posted April 28, 2006 Posted April 28, 2006 If your looking for good designs of larger scale kno3/su rockets, this guys site has a lot of experence and tutorials. www.inverseengineering.com
teknix Posted April 29, 2006 Posted April 29, 2006 Oh yeah I agree if you want to make engines bigger than F size then you are going to need to make different melted grains for the sugar fuels. Though you can get BP to work at larger engines sizes. I couldn't get a dry packed sugar G size engine to work at all reliably but F is about the largest I ever got to work 100% of the time with that method though I still consider F a pretty large engine.
ActionTekJackson Posted May 9, 2006 Posted May 9, 2006 I noticed this question was asked earlier, but no one answered it. Has anyone had any experience using other sugar forms? Say Sucralos for example, or even saccharin? I realize the ratios between oxidizer and fuel would definately change. Any thoughts on this?
Mumbles Posted May 9, 2006 Posted May 9, 2006 Experimentation and fun for one. Anyway, how do you know that sucrose is the best? Have you tried all the others? Sucrose does have it's downsides, and I don't know if I would consider it the best.
teknix Posted May 9, 2006 Posted May 9, 2006 Yeah Sorbitol and Dextrose are also good. I mean Sucrose is very hydroscopic which makes it work not so well. I think Sorbitol works much better for larger engines and is less hydroscopic. Can't really say what is best. Some sugars work better for different applications than others.
ActionTekJackson Posted May 9, 2006 Posted May 9, 2006 I mean Sucrose is very hydroscopic which makes it work not so well. Just a little note, the proper word is Hygroscopic, while Hydroscopic would make more sense, its not really a word. lol, anyway I was curious about the Sucralos being a chlorine donar. Maybe this would make colored rockets easier? Most KNO3/Sugar mixes don't produce a visible flame so that would cause a serious drawback. Hmm... nvm that might not work, possibly a mixture of BP, and some colored star mix?
teknix Posted May 10, 2006 Posted May 10, 2006 Good catch! I never really noticed that and seems like a lot of people spell it like that and I just looked over it and thought it made sense in my mind haha.
ActionTekJackson Posted May 11, 2006 Posted May 11, 2006 Hey, does anyone know how to measure the velocity of a stationary rocket? Can I measure the speed the gasses exiting the rocket and determin a rough flying velocity? I'm trying to design a rocket tester, I already have everything figured out to measure the rough burn temp. and the force the rocket exudes (will have to be measured in lbs). Anyone have any ideas for velocity? Seems I remember there being some formula I can use so long as I have the force of the rocket in newtons. I'm just tired of trying to determin better performance by eyeballing.
ActionTekJackson Posted May 11, 2006 Posted May 11, 2006 Nvm, did some more searching.... seems I'm gonna need to brush up on my math a bit...
ActionTekJackson Posted May 12, 2006 Posted May 12, 2006 Just a warning, I'm gonna need some help with some of these.Rocket Equations I'm still in the dorms, but I leave tomorrow, so ya'll still have some time before I start askin for some math lessons, lol.
Boomer Posted May 13, 2006 Posted May 13, 2006 We put our motors upside down on a scale (self made from spring + alu-lever with big wiper to read from a distance). Later we modified it to move a pen over a roll of paper turned by a toy motor, similar to what is used to record earth quakes. It could draw a thrust/time curve to calculate how high it would go with a given rocket weight. There are even professional gauges complete with A/D converter card for a laptop to take the curves. See the pro's pages (Dan, Wisser etc). You must expect spending some hundred bucks this way though.
ActionTekJackson Posted May 17, 2006 Posted May 17, 2006 Thats a really good idea, I knew I could use a scale, just couldn't quite figure out how to set it up. I have a fish scale that is made so you just hang the fish by a gill and it'll pull a spring down and give the weight. ITs pretty good size and has a pretty high weight max. Thanks!
Pyrohawk Posted May 17, 2006 Posted May 17, 2006 I know James Yawn made a thrust measurer out of a homemade 2x4 stand thing. It looks pretty easy to make and I think he got pretty decent measurements out of it....for its redneckness. He also has some of the fancy computer ones that he uses now.... Check out his site.... It' probably my favorite on KNO3/Sugar rockets.www.jamesyawn.com
[w00t] Posted May 17, 2006 Posted May 17, 2006 Hmm, if your using a rocket with a nozzle, wouldnt it CATO if you run a fuse in to the hole in to the propellent?
TheSidewinder Posted May 17, 2006 Posted May 17, 2006 Well....no, not necessarily. That's the way many rockets are designed to be lit.  Some are designed to be end-fired, and I usually end-fire mine if it's a BP rocket, even if it's cored. Certain Amateur rockets using APCP fuel grains need the ignitor right at the top of the core. Take a look here for more:  Wildman Rocketry and here: Ozark Propulsion Labs M
BigBang Posted May 17, 2006 Posted May 17, 2006 The ingiter should fit loosly up the core. When the grain ignites, the igniter is forced out through the nozzle. If the igniter is snug, it might cause a cato. With APCP motors, we sometimes get a cato with long, high thrust, fast burning motors (specifically I-200's by aerotech.) If the E match does not easily pass through the nozzle and up through the grain, you will have a problem. For getting a thrust curve of your motor, the scale method works ok. For a more accurate reading, you can use a load cell. These can be used for all sorts of motors, though they can get pricy. http://www.aeroconsystems.com/electronics/loadcells.htm
ltf Posted May 17, 2006 Posted May 17, 2006 ,May 17 2006, 07:13 AM] Hmm, if your using a rocket with a nozzle, wouldnt it CATO if you run a fuse in to the hole in to the propellent? If it cato it means that your core is to long. All of my rocket (BP and KNO3/su) have a nozzle and none of them catoed.most of my bp rockets are 1/2" by the sizes of passfire and to most of my KNO3/su propellant I ad 4% FeO3 as a catalyst.
Silverturk Posted May 20, 2006 Posted May 20, 2006 For larger rockets you can use zink and sulphur mixed (80 Zink, 20 sulphur). In this case, the sulphur will work as an oxidizer (im not that good in English). This is commonly used in large rockets.
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