Paris Gun

Also called the "Kaiser Wilhelm Geschütz" (Kaiser Wilhelm Gun), it is often confused with Big Bertha, the howitzer used by the Germans against the Liège forts in 1914, and indeed the French called it by this name as well. It is also confused with the smaller "Lange Max" (Long Max) cannons from which it was derived. Although the famous Krupp-family artillery makers produced all these guns, the resemblance ended there.

As a military weapon the gun was not a great success: the payload was minuscule, the barrel had to be regularly replaced, and the accuracy was only good enough for city-sized targets. However, the German objective was to build a psychological weapon to attack the morale of the Parisians; not to destroy the city itself.

Description

It was capable of hurling a 94-kg shell to a range of 130 km and a maximum altitude of 40 km - the greatest height reached by a human-made projectile until the first successful V-2 flight test in October 1942.

At the start of its 170-second trajectory, each shell from the Paris Gun reached a speed of 1,600 m/s (almost five times the speed of sound).

The gun itself, which weighed 256 tons and was mounted on rails, had a 28-m-long, 210-mm-caliber rifled barrel with a 6-m-long smoothbore extension.

Originally conceived as a naval weapon, the gun was manned by a crew of 80 Kriegsmarine sailors under the command of an admiral, and was surrounded by several batteries of standard army artillery to create a "noise-screen" around the big gun so that it could not be located by French and British spotters.
The projectile reached a maximum height of almost 40km, making it the first man-made object ever to reach the altitude of the stratosphere, thus virtually eliminating drag from air resistance, allowing the shell to reach super-sonic speed and achieve a phenomenal range of over 80 miles. Not until liquid-fuel ballistic missiles were developed 30 years later was this accomplishment equaled and finally surpassed. The shells were propelled at such high velocity that each successive shot wore away a considerable amount of steel from the rifle bore, and each shell was sequentially numbered according to its increasing diameter, and had to be fired in numeric order lest the projectile lodge in the bore and the gun explode. After 65 shells had been fired, each of progressively larger caliber to allow for wear, the barrel was rebored to a caliber of 240 mm.

The Paris Gun was the largest gun ever built for its time, only to be surpassed in World War II by machines such as the Schwerer Gustav or the V-3 cannon.

Use in World War I

The Paris gun was used to shell Paris at a range of 75 miles. The distance was so far that the Coriolis effect - the rotation of the earth - was substantial enough to affect trajectory calculations. The gun was fired at an azimuth of 232 degrees (west-southwest) from Crépy-en Laon, which was at a latitude of 49.5 degrees North. The gunners had to account for the fact that the projectiles landed 393 meters short and 1343 meters to the side of where it would have hit if there was no Coriolis effect.

A total of 320-367 shells were fired, killing 250 people and wounding 620, as well as causing considerable damage to property.

The gun was taken back to Germany in August 1918 as Allied advances threatened its security. The gun was never seen by the Allies; towards the end of the war it was completely destroyed by the Germans. One spare mounting was captured by American troops near Chateau-Thierry, but no gun was ever found.

Further reading