Fireworks and stability

[EBurg]

After a beautiful 4th of July filled with fireworks , I can't help but wonder. How do fireworks like bottle rockets maintain stability? I'm sure it has something to do with the stick, but can anyone explain it?

 

[Lowpuller]

The CG is ahead of the CP, thanks to the long stick!

 

[Zeus-cat]

And the stick acts like a fin, the same way a tail works on a kite.

 

[jsdemar]

I saw a J or K motor on a stick fly at an LDRS a long time ago. Made to look like a big bottle rocket.

 

[MClark]

There are guidelines on how long and heavy the stick needs to be and where the cg should be.

I was at an independent launch and at night there were rockets going up. Out of the darkness a voice shouts "M motor......on a stick!" It was an US Rockets Firestarter! Pretty spectacular.

M

 

[markburton]

I don't see how CP can get behind CG in a simulation (OpenRocket). The cross section is not enough to pull the CP lower than the nose.

 

[dhbarr]

I don't see how CP can get behind CG in a simulation (OpenRocket). The cross section is not enough to pull the CP lower than the nose.

Skin drag at nonzero AOA?

 

[Andrew_ASC]

Those mortar fireworks are extremely stable when fired from tube I prefer those over the boxes called silos that shoot a bunch of unstable tracer like darts all over and even horizontally.

 

[jsdemar]

I don't see how CP can get behind CG in a simulation (OpenRocket). The cross section is not enough to pull the CP lower than the nose.

The CG is far forward. The corrective moment (force at a distance) is larger for the stick because its CP is far away from the CG. The upper (unstable) moment due to the body tube in front of the CG is smaller because it is not very far from the CG. Subtracting the two moments, the stick wins.