1 lb rcandy stinger missiles - flies straight every time, some of the time...

[jl88]

Hey all, this is my first topic and am hoping you can help.

 

I have been making RCANDY rockets for some time and launching them as model rockets. They fly straight and were good fun. But now am movie into the fireworks world and am having trouble with these stingers.

 

The fuel is an RCANDY style powder. It is all the ingredients dissolved in water and then the water gently boiled out in a thermostatically controlled electric skillet. Once dry it is then broken up and powdered. The resulting fuel is very fast burning and much better than my best attempts at black powder. Ratio 65/34/1 kno3/sugar/fe2o3

 

Now the problems is, sometimes (50%) the rocket will go "near" straight up. However other times it seems to do a small loop straight out of the tube or pin I am launching from, build up enought stability/thrust and continue in a straight line on its merry way... (In whatever direction it may be pointing)

 

I have seen this in my early model rockets when the rockets centre of pressure was not far enough behind its centre of gravity causing it to become unstable. But with a stinger there are no fins or body to modify, so I'm a bit unsure were too start.

 

I have tried many launching platforms from short mortar tubes, long mortor tubes, short pins, long pins and everything in between. Maybe I'm missing something...

 

Anyway thanks in advance!

Jack

Edited December 21, 2013 by jl88

[leedrill]

hi ill say a common problem with stingers is people drill the hole too deep or to large that the time it takes to burn through to the core is too quick that it dose not get enough time to be a spin stabilse motor but after a second the nozzle allows enough back pressure to keep gasses exiting the side vent hole and get it spinning fast enough im unsure of your construction methods other than fuel really so please say if you think this is the problem or if it is definitely no

[jl88]

Thanks for the reply. I am using wolter pyro tools 1lb stinger tooling with a drill support. The tubes a spiral wound 3mm wall. (Where the hell can you get convolute in Australia! Lol)

 

Finally got them going straigh up pretty well all the time. Bigger the heading the less chance it goes verticle I'm noticing. By securing the launch pad to the ground with a tent peg or something similar seems to help it. I am just using a nail in the rockets core which seems to be working well now. Over 30 stingers going near straight up. With the exception of a few...