V-3 cannon

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Like the V-1 flying bomb and the V-2 rocket, the V-3 cannon (given the cover name Hochdruckpumpe ("High Pressure Pump") in German) was one of the three "vengeance weapons" (German: Vergeltungswaffe) planned by Nazi Germany during World War II. Unlike the V-1 and the V-2, however, the V-3 was not a guided missile, but a huge underground complex located in Mimoyecques, France. Some sources erroneously report the Wasserfall Missile as being the V-3. Sometimes the designation V-3 is applied to a never completed development of the V-2 that was intended to reach the East coast of the USA (the two stage A9/A10 missile of the Aggregate series).

[edit] Description

The complex contained five hidden batteries, each containing a single buried super-howitzer. The guns, with a barrel length of about 120 m, were the largest Axis artillery pieces, surpassing the Schwerer Gustav or Dora railway-propelled 800 mm super-cannon, the Mörser Karl (Gerät 040) 600 mm tracked siege mortar, and the Leopold and Robert 320 mm railway cannons. The calibre was 150 mm and the shell weight was 140 kg.

The technological innovation employed by these huge guns was the use of multiple propelling charges, placed along the barrels' length and timed to explode as soon as the projectile passed them by, to provide an additional boost. Due to their higher suitability and ease of use, rocket boosters were used instead of explosive charges, arranged in symmetrical pairs, attached to the barrel with a low (below 30º) angle. This layout spawned the German codenames Hochdruckpumpe ("high-pressure-pump") and Tausendfüßler ("millipede").

These guns had a muzzle velocity of 1500 m/s and the whole complex was designed to be capable of shooting 300 shells every hour, with a maximum range of 165 km.

It was of course very hard to aim even a single gun, but that was not much of a problem since the complex had been built and oriented with the sole purpose of attacking London from a safe distance. This leads to its alternate name, the London Gun.

The complex was never used for its intended role, and only fired test shots before being destroyed by bunker buster Tallboy bombs dropped from British Lancasters of the No. 617 Squadron, the "Dambusters" on 6 July 1944^[1]. However, the success of the 6 July bombing raid remained unknown to the Allies, who continued their efforts to destroy it until the complex was captured. For instance, one of the intended targets of the failed Operation Aphrodite (using remote controlled aircraft filled with explosives) was the Mimoyecques V-3 complex^[2]. After Mimoyecques was occupied by the Allies the British sent in a demolition team which damaged the guns and destroyed the entrance points to the galleries.

The destruction of the Mimoyecques complex was not the end of the V-3 program, as two shorter-barreled cannons were set up in Lampaden, 13 km southeast of Trier in Germany. From December 30, 1944 to February 22, 1945 the two guns fired some 183 shells at Luxembourg (range 43 km) killing 10 civilians and wounding 35^[3]. Soon after the last shell had been fired the firing site along with the disassembled cannons was captured by advancing American forces and the equipment was sent back to the US where the cannons were tested and evaluated at the Aberdeen Proving Ground before being finally scrapped in 1948.

Along with the V-1 and V-2 missiles, the V-3 was a desperate attempt to retaliate against the Allied heavy bombing raids over Germany. It was intended that a total of 50 V-3 cannons be built in all. The resources available to the German V-rocket project were unable to compete with the devastating impact of the heavy bombers, though, and clearly show the serious problems faced by the Luftwaffe during the last years of the war.

Some portions of the tunnels have since been cleared out and a museum now allows visitors to explore the galleries and view a few of the remains of the guns.

[edit] Further reading

Paul Brickhill The Dam-busters, ISBN 0-330-37644-6. First published 1951 Tells the story of the 617 Squadron and their weapons.
Pas de Calais - France - V3 Base
(French)Fortress Of Mimoyecques