What is the principle of double-sounding gun?

The principle of double-ring gun rack is that the powder is placed in the paper tube of double-ring firecrackers in two layers. The lower gunpowder is used to send firecrackers to the sky, and the upper gunpowder explodes in the air after taking off 10-20 meters.

The "back door" at the bottom of the two guns was not blocked tightly, and the airflow generated by the lower gunpowder explosion broke through the back door and sprayed downward. The downward jet of air generates upward thrust, pushing firecrackers into the air. At this time, the fuse just ignited the gunpowder sealed at the top, which burned-it exploded again soon, and the two kicks blossomed in mid-air. Fireworks also rely on the thrust generated by the rapid combustion and explosion of gunpowder.

Erjijiao, commonly known as Liangrang, is a kind of firecrackers, and its powder is divided into two layers. The gun barrel is divided into two parts by mud, and the middle part is connected by lead twist. The lower bucket is loose at the top. When the explosive explodes, the energy is released from the top, and the barrel does not break, making the whole gun fly into the sky. During the first explosion, the intermediate connection is ignited for twisting, and when the gun is in the air, a second sound occurs.