Fritz X

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Fritz X


Steering bomb Fritz X

General Information
Designation: X-1, PC 1400X or FX 1400
Type: Anti-ship missiles / precision guided ammunition
Country of origin: German Empire
Manufacturer: Ruhrstahl
Development: Max Kramer
Commissioning: July 21, 1943
Working time: 1943-1945
Technical specifications
Combat weight: 1570 kg
Length: 3262 mm
Diameter: 562 mm
Span: 1352 mm
Range: 5 km horizontally
Furnishing
Warhead: 320 kg of Amatol 40
Steering: amplitude-modulated radio remote control on frequency 50 MHz with transmitter FuG 203 (code name "Kehl") and receiver FuG 230 ("Strasbourg")
Detonator: Unknown (possibly dismantling fuse)
List of bombs by country of origin
Fritz X

Fritz X was the most common name for a remote-controlled drop bomb that was developed by the German company Ruhrstahl during World War II under the direction of Max Kramer . The weapon was manually guided to the target with a radio remote control (today called MCLOS ) and was designed for use against ship targets, but was also used against land targets.

The Fritz X was the first guided bomb in the world to be mass-produced and is therefore one of the predecessors of anti-ship missiles and precision-guided ammunition .

Development history

Max Kramer from the DVL was already experimenting with remote-controlled free-falling bombs weighing 250 kg from the late 1930s. In 1940 Ruhrstahl AG was included in the development.

The first experiments were with the explosive bomb SD 1400 ( S plitterbombe, d ickwandig, 1,400 kg) instead, then the PC was used 1400th Other names for the bomb were X-1, Ruhrstahl SD 1400 X, PC 1400X or FX 1400; the name Fritz X is derived from the latter . The X stands for the guide surfaces arranged in the X shape.

Basic technical structure

The Fritz X was based on the tank explosive bomb PC 1400 ( P anzerbombe, C ylindrisch, 1400 kg) developed. With its thick walls, this was specially developed for armored warships to penetrate armor plates up to 20 cm thick. It now got a more aerodynamically designed tip, four stub wings with a wingspan of 1.40 m and a box-shaped tail unit . At the stern, five sets of lights were attached within the tail unit, which served as aids in targeting. The color of the flares could be chosen so that the bombardiers could distinguish the Fritz X who were in the air. In addition, dimmed light sets were provided for use in twilight. A gyro control served to stabilize the longitudinal axis and a remote control receiver to control the elevator and ailerons . Via a radio remote control with 18 channels in the frequency range around 50 MHz, consisting of the transmitter FuG 203 (code name "Kehl"; on board the aircraft) and the receiver FuG 230 "Strasbourg" (in the missile), the missile was targeted from the carrier aircraft steered. In order to deceive the opposing side, transmission was also carried out on unused frequencies. As an alternative to radio control, wire steering (two 8 km wire spools in the aircraft and two steering bombs) was developed in order to be ready for use in the event of enemy radio interference. However, effective radio interference was not observed.

Another route guidance, which only came up to testing, was the “Radieschen” system, with which the Fritz X was supposed to independently control broadcasting facilities such as British “ Chain Home ” radar stations. A forerunner of the HARM missiles. The "FB" (television picture) control (also called "Tonne" / "Seedorf") was developed with which the image from a camera ("Tonne") in the Fritz X is transmitted by radio to the "Seedorf" television receiver in the aircraft in order to enable route guidance.

Hit probability

During test drops in Peenemünde and then in Foggia , 50% of Fritz X's drops from 4000 to 8000 m were in a circle of 14 m (CEP 50 = 14 m). All fully functional Fritz Xs hit a circle 26 m in diameter.

Technical procedure in use

The bombardier had to keep the weapon always in cover with the target using a so-called “command transmitter with a movably mounted steering rod” (similar to today's joysticks ). This had the disadvantage that - in contrast to glide bombs like the Henschel Hs 293  - the target had to be flown over. The observer determined the time of the drop with a conventional 7D bomb sighting device (“Lotfernrohr”). After disengaging the Fritz X, the pilot had to go into a climb in order to slow down the aircraft appropriately so that it flew over the target until the moment of impact - approx. 30-40 seconds after dropping - and the observer optimally uses the flare for tracking could pursue. This made the attacking aircraft theoretically vulnerable to heavy anti-aircraft guns, but losses in this phase are not known.

commitment

The Fritz X came to the troops on August 29, 1943. On 9 September 1943, the could Luftwaffe her greatest success has been achieved with this weapon: After the armistice the Allies with Italy , the Italian ran fleet from La Spezia and headed for Malta to surrender to the Allies. Twelve Dornier Do 217 combat aircraft of the III. Group of Kampfgeschwaders (KG) 100 started with one Fritz X on board from Marseille in southern France to attack the unit. The Italian battleship of the Littorio class , the Roma , the flagship of the Italian fleet with 43,624 tonnes, received two hits and sank after an explosion. The first hit hit the stern and penetrated the bottom of the ship, presumably without detonating. The second momentous hit hit an ammunition chamber amidships, whereupon a powerful detonation tore the ship in two and led to its sinking. With 1393 men, a large part of the crew died, including Admiral Carlo Bergamini ; 595 men survived. The sister ship Italia was damaged. The search for the place where the Roma went under was unsuccessful for a long time. In a press release on June 28, 2012, the Italian Navy announced that an underwater robot had found the Roma wreck at a depth of around one thousand meters, around 16 nautical miles off the north coast of Sardinia.

Hit by a "Fritz X" guided bomb on the USS Savannah on September 11, 1943 off Salerno during Operation Avalanche

A Fritz X was dropped on the nunnery of the city of Cospicua on the island of Malta , which housed part of the docks and the base of the British Navy.

As part of the defense against invasions in August 1944, Fritz X were also used against bridge targets for the first time , but the success during the invasion of northern France was not achieved due to the strong threat from hunters. The last missions with the Fritz X took place in April 1945 against the Oder bridges.

In 22 missions, the KG 100 carried a total of 108 Fritz Xs up to April 30, 1944 , of which 60 were thrown at the target (44 worked, 16 technical failures). Of the 44 functioning specimens used, 14 scored direct hits, 7 effective close hits, 13 missed throws and 10 times the hit position was not observed.

When the Allies captured the Foggia airfield in southern Italy on September 27, 1943, Fritz X fell into their hands, but this remained unknown to the German side.

A total of around 2500 drop bombs were built. But only a small part of this was used at the front, as the Allied air superiority and above all the lack of suitable German carrier aircraft such as the He 177 made the use of this effective weapon more difficult.

Ship hit

Other ships that were damaged or sunk by Fritz X during the war were:

See also

literature

Web links

Commons : Fritz X  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ Sven Felix Kellerhoff : When the Wehrmacht dropped the first clever bomb in: Die Welt , September 9, 2013
  2. ↑ Wolfgang Fleischer: German dropping ammunition until 1945: High explosive bombs, incendiary bombs, special dropping ammunition, dropping containers, detonators , Verlag Motorbuch, 2003, ISBN 978-3-613-02286-7 [1]
  3. ^ Rowland F. Pocock: German Guided Missiles of the Second World War . Arco Publishing Company, 1967, p. 104 .
  4. ↑ a b Benecke / Hedwig / Herrmann: Missiles and guided missiles , Bernard u. Graefe Verlag, 1999
  5. ^ Italian WWII ship found off Sardinia  - time online
  6. ^ The National War Museum, Valletta, Malta
  7. ^ Bill Gunston: The Illustrated Encyclopedia of the World's Rockets and Missiles. Salamander Books, 1979, pp. 106-107.
  8. ^ H. Nowarra: The German air armament. Volume 4, p. 77.