How Firework Shells Work

In FWsim, you can build your own virtual fireworks by combining components.
In order to create your own realistic fireworks, it is helpful to know how real fireworks work.

Aerial Shells

Pyrotechnicians don’t use rockets, but shells. FWsim can simulate both shells and rockets.

A shell used in a professional fireworks display. A shell used in a professional fireworks display. (Image Credit: bitslammer /

The shells are fired from metal or plastic pipes (mortars). A small amount of black powder propels the shell into the air.

Shells reach their maximum velocity right after leaving the mortar and slow down until they reach their maximum height. Rockets, on the other hand, have their own propulsion and still accelerate while in the air.

As soon as the shell is fired, a fuse starts burning inside it. It burns for several seconds and then triggers the explosion (“bursting charge”). In general, the shell is designed to explode at its peak.

The explosion ejects several burning stars.

Multibreak Shells

Multibreak shells explode multiple times: A part of the shell explodes and releases stars, while another part continues flying upwards. These shells have a cylindrical shape and usually consist of several components, connected with delay fuses.

Illustration of a multibreak shell, made by FWsim user 
Josué Beauregard

Simulation in FWsim

FWsim simulates the shells physically accurate. You can select the launch velocity and the size of the shell. Alternatively, you can just select the size of the shell, and FWsim chooses all the parameters automatically.

To create a multibreak shell, simply add several explosions to a shell.

For more information, please refer to the Effect Editor Manual.