47 replies to this topic

[pyromaniac303]

I usually avoid this problem by only ramming about 1/2" above the core, on a standard 1/2" rocket tooling, it has just over a 3" core, then I ram between 1/2" and 1" of propellant, usually with +5" aluminium or iron powder added to give the last few seconds an effect. After this just 1/4"-1/2" of clay then I have a small amount of space at the top of my 5" tube.

[pendulum]

Thanks for the reply. I think I'll do what you do and just not ram very far above the spindle. I've made another rocket and I am more confident that this one will go "bang" in the sky and not on the ground. It is too late to test it tonight, so fingers crossed for tomorrow.

What I did wrong with the rocket I made above is I had about 1 1/2" of compacted BP that burnt like a fountain, by the time it had burnt through and ignited the quickmatch the rocket had landed! Duh! This time the tube is a lot shorter and there's way less BP between the end of the core and the quickmatch.

[Mortartube]

Make the core longer, or pack less of a solid header over the top of the core. Many people have a core length of around 7/10 ths of the entire BP charge.
How long and what ID are your cases?