Rotating gas-check facts for kids
A rotating gas-check was a smart copper plate used with large cannons, especially those called rifled muzzle-loading (RML) artillery. It was also known as an automatic gas-check because it attached itself to a special cannonball, called a "projectile." Its main job was to stop gas from escaping when the cannon fired and to make the cannonball spin as it left the barrel. This spin helped the cannonball fly straight and hit its target accurately.
What Was a Rotating Gas-Check?
A rotating gas-check was a round piece of copper, a bit like a thick washer. It was designed to fit perfectly onto the back of a special cannonball. When the cannon fired, the force of the explosion pushed the gas-check tightly against the cannonball and the inside of the cannon barrel.
How Did It Work?
When a cannon fires, a lot of hot gas is created very quickly. If this gas escapes around the cannonball, it can reduce the power of the shot. The rotating gas-check acted like a seal, stopping the gas from leaking out. This meant all the gas pushed the cannonball forward with full power.
Another important job of the gas-check was to make the cannonball spin. RML cannons had special grooves, called "rifling," inside their barrels. As the cannonball moved down the barrel, the gas-check would grip these grooves. This made the cannonball rotate, much like a football spins when thrown. Spinning makes the cannonball more stable in the air, helping it fly further and more accurately.
Why Were They Important?
Before rotating gas-checks, some cannonballs had "studs" that fit into the rifling grooves to make them spin. However, these studs could sometimes get damaged or not work perfectly. The automatic gas-check was a newer, more reliable way to make sure the cannonball spun correctly every time. This invention helped make cannons more powerful and accurate during the time they were used.
Gallery
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1. A Palliser Shell (a type of cannonball) with an automatic gas-check.
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2. A Common Shell (another type of cannonball) with an automatic gas-check.
See also
