As a military historian with a focus on ordnance, I can provide you with a detailed explanation of how long it takes for a grenade to explode.

Grenades are a type of explosive device that have been used in warfare for centuries. They are designed to be thrown or launched to detonate near a target, causing damage through the force of the explosion and the fragmentation of the grenade's casing. The time it takes for a grenade to explode after being activated is a critical factor in its effectiveness and safety for the user.

The delay mechanism in a grenade is known as the fuse or the delay timer. This is designed to provide a brief period between the activation of the grenade and the detonation, allowing the thrower to escape the blast radius and avoid injury. The length of this delay can vary depending on the type of grenade and the intended use.

In the early days of grenade development, fuses were often quite long to give soldiers ample time to throw the grenade and seek cover. However, as you mentioned, during the Battle of France in 1940, it was discovered that a seven-second delay was too long. Defenders had enough time to either escape the blast or, worse, throw the grenade back at the attackers. This realization led to a reduction in the delay time to improve the grenade's tactical effectiveness.

Most modern grenades have a delay of around four seconds. This is considered a balance between giving the user enough time to throw the grenade and ensuring that it detonates quickly enough to catch the enemy off guard. The four-second delay is also a safety measure to prevent the grenade from being thrown back effectively.

The fuse of a grenade typically consists of a percussion cap that is struck by a firing pin when the safety pin is removed and the handle is released. This ignites the primary fuse, which in turn ignites the secondary delay fuse. The secondary fuse is what determines the delay before detonation. Once the delay has expired, the fuse ignites the main charge, causing the grenade to explode.

It's important to note that the delay time can vary slightly from one grenade to another due to manufacturing tolerances and the specific design of the fuse. Additionally, environmental factors such as temperature and humidity can also affect the burn rate of the fuse, potentially altering the delay time.

In summary, the time it takes for a grenade to explode is a carefully calibrated feature that balances tactical effectiveness with user safety. While a four-second delay is common in modern grenades, the actual delay can vary based on the specific model and conditions. Understanding these factors is crucial for the safe and effective use of grenades in military operations.

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At first, the grenade was fitted with a seven-second fuse, but during combat in the Battle of France in 1940, this delay proved too long, giving defenders time to escape the explosion or to throw the grenade back, so the delay was reduced to four seconds.read more >>