These days I watched a video of a strange fireworks device I have never seen and discovered it's name is "Double Voice Cracker". Today I will tell you what I have learned about it.
Also known as Heaven and Earth or Bing Bong, Double Voice Crackers are a chinese type of firecracker that essentially produces 2 bangs, one in the ground an another in the air. It is like a mortar and shell self contained in a single tube divided in the middle by a clay (or other hard material) plug with a timing fuse.
Below is a diagram of a Double Voice Cracker from the book "The Best of AFN II":
Before igniting the fuse, the device must be placed over a hard and flat surface with the lifting charge facing the ground. When the fuse is ignited, the lifting charge explodes and kicks the tube into the air, while igniting the time fuse and finally the report charge explodes in the air. The report charge could be flash powder or any other effect. For more safety and predictability, some people made a special launch base composed of a short steel tube (like a mortar) soldered on a hard base.
Here is an Youtube video showing a 3 inch Double Voice Cracker:
Comments1
Double Voice
I wrote that article you excerpted. Also wrote a follow up piece with an improved design, but I don't remember if that was re-printed. I have a copy, but your format doesn't lend itself to sharing.