9 replies to this topic

[Caramanos2000]

Ok, I made some kno3/sugar/iron Oxide rockets. Cast into my homemade 1/4" tubes with some kind of concrete mix for nozzle. I set off 2 of them with the same result. They took off about 2' then went sideways forever. How could I solve this, I dont think I am lacking in power. Perhaps a larger nozzle for a higher impulse for less time? Or a larger stick? Even after flying for a while they continue to burn for a long time.

[seymour]

If they are not lacking thrust, then yes, there are stability issues and a longer stick may be in order. However among other things, the long burn time suggests otherwise. Sugar burns fairly fast, and a rocket of that size should burn out in >1 sec. Moisture can greatly reduce the burn rate of nitrate/sugar fuels, so if you are not doing this already, I would recomend ensuring that your chems are dry before beginning the casting process. Without more details such as core, stick and nossle dimensions there is little more I can say.

Also, I am sure there is a more appropriate place to ask for rocket advice than a new thread, there is an entire rocketry section on these forums!

[Caramanos2000]

Motor casing is about 3" long and 1/4" wide. Nozzle is 1/8". Stick is a kibob stick.

[seymour]

Core?

[Caramanos2000]

1/8". Thanks to the mods for the move .

[seymour]

Give it a full length core. Even if catalysed Potassium nitrate sugar is able to be used in end burning rockets the nossle should be much smaller tha half the ID, however 1/8" will be fine with a good core.

[Caramanos2000]

Is my size core adequate? You do mean core from one side to the other. Also my rcandy seems to get cold fast sometimes before i can get it into the motor, what can I do?

[seymour]

From what you have said I can assume you have NO CORE, yes, it should go from one end to another. Realy, you just need to act fast, and/or swap from Sucrose to Dextrose, which has a lower melting point. Good luck...

[Caramanos2000]

Is a 1/16" nozzle better?

[seymour]

The nossle is fine 1/8", just make sure that you have a central cavity the full length of the fuel. If it sets too fast for you to form it while it is soft, then wait till it is fully cooled and you can slowly drill into it.