sjaak Posted August 18, 2015 Posted August 18, 2015 I have some questions about firesmith's 1lb Universal rocket tool, hope you guys can help! some months ago i pressed a couple whistle rockets with this tool, i ussed 76 potassium perchlorate, 23 potassium benzoate, 1 copper oxychloride, +3 mineral oil.I pressed the rockets all the way to the top and used a bentonite bulk head (no payload). Great rockets but they disappeared through the clouds. i'm planning to press more whistle rockets to lift 4 inch can shells but how much inch do i need to press above the spindel?How much can i lift with this 1lb rockets and potassium benzoate whistle mix?How long can i store the rockets (in ziplock bags)? unfortunately i don't have much possibility to test rockets here in my area so hopefully you guys can help.
calebkessinger Posted August 19, 2015 Posted August 19, 2015 I watched one of those sets with benny whistle lift 6 in ball shells last week.. they weren't too high but it did it. You are over powered for 4 in shells. fives would be about right with around 1 in from the top of spindle to the top of the whistle delay. Most people just lift salutes into the stratosphere with that set up.
schroedinger Posted August 19, 2015 Posted August 19, 2015 (edited) If i remember right it was mkn doing quite some test on that topic about half a year ago. He got the 1 lb rocket to lift about 1 kg which is a 6". So you propably should think about hybrid rockets or a slower whistle comp. Edited August 19, 2015 by schroedinger
sjaak Posted August 20, 2015 Author Posted August 20, 2015 (edited) I know these rockets are very powerfull but 6 inch that is crazy But i'm planning to lift 4 inch canister shell's with these rockets. I believe a 4 inch can shell is approximately the same weight as a 5 inch ball shell (around 600gram) right? So with 4 inch canister shell's and 1 inch pressed above the spindel i be on the safe side and the shell won't break to low? Edited August 20, 2015 by sjaak
calebkessinger Posted August 20, 2015 Posted August 20, 2015 Test test test. dummy shell with some chalk and a small burst charge will do the trick. Kitty litter for weight, dog food, anything inert that will get to the weight you need.
sjaak Posted August 20, 2015 Author Posted August 20, 2015 i know testing is best but i don't have much possibility to test rockets here in my area But thanks for the help i will start with 1 inch above the spindel and around 600 grams for testing. how long can i store these rockets, they need to stay reliable? i believe i read somewhere you can store them for 1 month but i'm not sure.
schroedinger Posted August 20, 2015 Posted August 20, 2015 If you pack 'em airtight and seal the ends with Al tape, they work good after 1 year. Tipp you only need to store the engine sealed, the header can be left of and attached on the day of flight. Saves a lot of space.
dagabu Posted August 21, 2015 Posted August 21, 2015 I heard it time and time again at PGI this year, light whistle rockets the same day if possible. I cannot count the people on APC that have posted about whistle rockets CATOing, "the fuel is too hot", "the stick is too long", "there is too much pressure on the comp", "there is too little pressure on the comp", on and on it goes but the universal truth is that of the whistle rockets that perform well the day they are made, many, many CATO in a few as a few days later. I pressed a dozen #1 Benzoate rockets at PGI on Sunday and flew two that night before the show. They worked fine. Monday night, one blew and the other was fine, same thing Tuesday night, the remaining all blew Wednesday night. I also made a dozen whistle with BP in various increments below the spindle, none blew up so I know I was on the ragged line with the all whistle rockets. My opinion on your rocket motors? Make a few and test them, one each week for a month. See if they start to pop or not. If they do, make more but use increments of BP below the spindle end to tame them down some. Once you know where the motors will pop, decrease the oxidizer by 5% and see if that solves your issue or not.
sjaak Posted August 28, 2015 Author Posted August 28, 2015 i believe i read that if you store the motors the core could crack which cause cato's but i didn't know this could happen after a few days.I need around 20+ reliable rockets unfortunately i can't press that much rockets and attach the payload in 1 day. what would you think is the most powerfull and relaible rocket with this tool and can be stored for longer time?maybe 60/30/10 bp but the max you can lift is 300gr i think? i only pressed nozzleless bp rockets and whistle motors but for nozzleless rockets i need a lot of fast bp and my ball mill is not that big.maybe hybrid rockets will work but i have no idea how to make them?
Bensmith Posted August 28, 2015 Posted August 28, 2015 I'll pop in here and do my best to answer the questions that have popped up... 6" shells on a 1lb motor can most certainly be done. It's a challenge, but certainly possible. My preference is to use 4" ball shells on my 1lb motors. They seem to reach a nice display height. On the Universal spindle, if you are not using a clay bulkhead (I don't) run your fuel to about 1" from the top of the tube. Depending on the weight of your shell and the speed of your fuel, you should be fairly close to a good height for your shells. Play around with your fuel a bit. I use 3% Vaseline dissolved in lacquer thinner with every fuel I make. I did some side-by-side comparisons with the aforementioned lubricant and 3% mineral oil dissolved in Coleman fuel. The Vaseline & lacquer thinner technique produced a stronger fuel that was easier to work with. I've stored my whistle and strobe rockets for 8-9 months just sitting in my day box. They worked as good as the day they were pressed. The only difference I noticed was the green strobe wasn't quite as bright green as when the fuel is "fresh". I do have tutorials on my site at www.firesmithtools.com that may answer a few additional questions. You can also email to ben@firesmithtools.com should you wish. -Ben
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