THEHODSONATOR Posted September 21, 2012 Posted September 21, 2012 Hi everyone. I think i understand the different converging and diverging angles and so forth. and i understand the length of a motor is roughly 10 times the ID of the motor. where I'm going astray is the actual opening diameter of the nozzle. So finally my question is: is there a formula that relates the diameter of the nozzle opening to the diameter of the motor? is there a rule that is along the lines of : the size of the nozzle opening is say 1/4 the inner diameter of the motor ? Cheers
dagabu Posted September 21, 2012 Posted September 21, 2012 Please take a look at my response to your first post, just use the rocket took sketcher at this web site. http://www.flashnet.dk/rts/ -dag
THEHODSONATOR Posted September 21, 2012 Author Posted September 21, 2012 what sorcery is this? this is like deep thought from hitchhikers guide to the galaxy: it has every answer but yet subtly veiled. THANK YOU!!
THEHODSONATOR Posted September 21, 2012 Author Posted September 21, 2012 HAHA! I can tell already that this place is a friendly environment. glad I came!
papasmurf Posted October 30, 2012 Posted October 30, 2012 (edited) Finally making my first post! I too have been wondering the same thing. However, I noticed they do not have any options for a sugar rocket on the tool sketcher. Which option would better represent a tool that can be used for sugar rockets?Thanks Edited October 30, 2012 by papasmurf
dagabu Posted November 1, 2012 Posted November 1, 2012 Papa, I use the Universal Hybrid tooling design for my pyro related R-Candy rockets but you can use the Long Winded Screamer tooling design from RTS if you wish. The main problem with using this tooling is the obvious depth of the of the hollow around the spindle and the improbability of getting a solid fuel grain without making air bubbles that cause problems with the burn. I have found that if you make your R-Candy according to Jacobs Dry Compressed method, you will often get BP like performance using a clay nozzle and a normal BP tube. If you want to have a better impulse, I have another novel way of using the uncast R-Candy fuel that is darn close to the same impulse that you get from Bates Grains of cast fuel. This is an inhibited burning grain since if is pressed like BP rather then poured into grains and is pressed into the tube walls making it impossible for it to burn at the same time as the core. I suggest using powdered sugar right from the grocery store to start with. I have found that C&H pure cane sugar works better than does off brands and only costs pennies more per ounce. Make your R-candy as you normally do and then let it cool to to the the point that you can handle it but not to the brittle stage, it will be too hard to grate. Use a cheese gator and make fine granules of R-Candy in a single layer on wax paper, let cool and dry them in a food dehydrator, drying box or a well desiccanted container. I have found that it is more important to choose the weather carefully then with any other type of rocket fuel, if the humidity is above 30% and the temp is above 50° F, the granules will stick together and your fuel will be useless. The rammer will also be impossible to pull out of the tube once pressed. For this reason, I only make these in the winter when the humidity and temp are in my favor. I use a NEPT tube (any ID is fine if you have the tooling) and a 1/2 ID increment scoop which is a teaspoon for the .75" ID tubes. I add 8g of my favorite clay nozzle mix and press it to 9000LPI then tap out the extra clay, add one spoon of fuel and press it to 5000LPI in 1/2ID increments all the way up to the top of the spindle. I tried a delay of Legendary Smoke above the spindle but you have to be careful since it burns so much slower then the R-Candy does. The last one I shot had only 3/8" of Legendary Smoke delay topped by 2 increments of BP and the delay was way too long, perhaps 1/4" would suffice. Good luck and show us video of your rocket, even if it is a failure, we like to see what others have come up with. I have several that I was going to launch at FFFF for a friend that I may be able to shoot this winter on the lake. These rockets make a superb contrail with a clear blue sky and will travel quite a ways. -dag
papasmurf Posted November 2, 2012 Posted November 2, 2012 (edited) Wow, thanks for all the detail. The grated r-candy has perked my interest. Looks like I might give that a try now that winter is in full swing here. I'll have to get some good media for moisture absorption, since I do not have a dehydrator. Edited November 2, 2012 by papasmurf
dagabu Posted November 2, 2012 Posted November 2, 2012 Try Craigslist, I got mine for $10.00. Also, I have been dissolving both my KNO3 and Sugar in hot water beforehand, this method makes for faster production of R-Candy and a harder grain. It also helps keeping the mix from caramelizing which robs burn speed. KNO3: 133 g/L (0 °C), 383 g/L (25 °C), 2470 g/L (100 °C)Sugar (Sucrose): 2000 g/L (25 °C) -dag
Recommended Posts