The Fritz X armor-piercing bomb, also known as the Ruhrstahl X-1, is striking testimony to German technical ingenuity in World War II. It was the first precision-guided weapon to be deployed in combat and the first to sink a ship in combat.

The development of controllable bombs began in the late 1930s under Max Kramer at Deutsche Versuchsanstalt für Luftfahrt, Germany’s  experimental aviation laboratory, in Berlin-Adlershof. Of several prototypes tested, only the X-1 made it through trials to reach production in 1943. The weapon was revolutionary. The 1,400-kilogram armor-­piercing bomb was fitted with stabilizing wings on the front casing and an enclosed tail section with four fins and attached spoilers—all of which could be controlled by radio from a Dornier 217 bomber. Bombardiers would typically let the bomb free-fall from about 20,000 feet (giving it a range of about 11/2 miles) and steer it to its target with a joystick linked to a radio transmitter. Flares on the tail helped bombardiers track the bomb through the bombsight.

The Germans used the Fritz X to sink or damage several Italian, British, and American warships in the Mediterranean, but its most high-profile success came on September 9, 1943, when several of the radio-controlled bombs sank the Italian battleship Roma and severely damaged the Italia as they were surrendering to the Allies. But because Germany produced only a small number of the bombs, they had little impact on the course of World War II. In time the Allies developed various electronic countermeasures to interfere with the Fritz X’s guidance system, and the need for the command aircraft to fly slow and level meant that many of the Do 217s were easy targets for Allied fighters. MHQ

Chris McNab is a military historian based in the United Kingdom. His most recent book is The Samurai Warrior Operations Manual (Haynes Publishing, 2019).

This article appears in the Autumn 2019 issue (Vol. 32, No. 1) of MHQ—The Quarterly Journal of Military History with the headline: Weapons Check | Fritz X

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