Fritz X

Infobox Weapon
name= Fritz X


caption= side view
origin= Nazi Germany
type= anti-ship missile / guided bomb
is_ranged=
is_bladed=
is_explosive=
is_artillery=
is_vehicle=
is_missile=yes
is_UK=
service= 1943 - 1944
used_by= Nazi Germany (Luftwaffe)
wars= World War II
designer= Max Kramer
design_date=
manufacturer= Ruhrstahl
unit_cost=
production_date=
number=
variants=
weight= 1,362 kg (3,000 lb)
length= 3.32 m (11 ft)
part_length=
width= 1.40 m (5 ft)
height=
diameter= 85.3 cm (2 ft 8 in)
crew=
filling= amatol explosive, armour-piercing
filling_weight= 320 kg (705 lb)
detonation=
yield=
armour=
primary_armament=
secondary_armament=
engine=
engine_power=
transmission=
payload_capacity= 320 kg (705 lb) amatol explosive, armour-piercing
fuel_capacity=
pw_ratio=
suspension=
clearance=
vehicle_range= 5 km (3 miles)
speed= 343 m/s (1,235 km/h or 770 mph)
guidance= Kehl-Strassburg FuG 203/230; MCLOS

Fritz X was the most common name for a German air-launched anti-ship missile, used during World War II. "Fritz X" was a nickname for the weapon used both by Allied and Luftwaffe personnel. Alternate names include Ruhrstahl SD 1400 X, Kramer X-1, PC 1400X or FX 1400. The latter is also the origin for the name "Fritz X". Along with the USAAF's similar Azon weapon of the same period in World War II, it is one of the precursors of today's anti-ship missiles and precision-guided weapons.

History

The Fritz X was a further development of the high-explosive bomb SD 1400 ("Splitterbombe, dickwandig, 1400"; German for "fragmentation bomb, thick-walled, 1400 kg"). It was given a more aerodynamic nose, four stub wings, and a box shaped tail unit. The "Luftwaffe" recognized the difficulty of hitting moving ships during the Spanish Civil War. [Fitzsimons, Bernard, ed. "Fritz-X", in "The Illustrated Encyclopedia of 20th Century Weapons and Warfare" (London: Phoebus, 1978), Volume 10, p.1037.] "Dipl. engineer" Max Kramer, who worked at the DVL, had been experimenting since 1938 with remote-controlled free-falling 250 kg bombs, and in 1939 fitted radio-controlled spoilers. [Fitzsimons, "Fritz-X", p.1037.] In 1940, Ruhrstahl was invited to join the development, since they already had experience in the development and production of unguided bombs.

Procedure for Combat

The Fritz-X was steered by an operator in the launching aircraft. The steering signals were communicated over a radio link between the aircraft and the weapon. The crewman who guided the bomb had to be able to see the target at all times, and the bomb had a flare in the tail so it could be seen from the controlling aircraft. The disadvantage with this - in comparison to glide bombs like the Henschel Hs 293 or VB-6 Felix - was the aircraft had to be flown over the target on a steady course at slow speed.

Unlike the Hs 293, which was deployed against merchant ships and light escorting warships, the Fritz X was intended to be used against armoured ships such as heavy cruisers and battleships. The minimum release height was convert|4000|m|ft and a release height of convert|5500|m|ft was preferred assuming adequate visibility. The Fritz X had to be released at least convert|5|km|mi|0 from the target. The plane had to decelerate upon bomb release so momentum would carry the bomb in front of the aircraft where the bombardier could see and guide it. This decceleration was achieved by making a steep climb and then level out. The bombardier could make a maximum correction of convert|500|m|ft in range and convert|350|m|ft in bearing. The bomber was vulnerable to fighter attack as well as ship-based air defense weapons while maintaining a slow, steady course so the bombardier could maintain visual contact to guide the bomb.Bogart, Charles H. "German Remotely Piloted Bombs" "United States Naval Institute Proceedings" November 1976 pp.62-68] When working properly, the missile was able to pierce 130 mm (5.1 in) [Fitzsimons, "Fritz-X", p.1037.] of armor.

Combat service

The only Luftwaffe unit to deploy the Fritz-X was "Gruppe" III of "Kampfgeschwader" 100, desginated III./KG 100. This unit employed the medium range Dornier 217 K-2 bomber on almost all of its attack missions, though in a few cases toward the end of its deployment history, Do 217 K-3 and Do 217 M-11 variants were also used. The Fritz-X had been initially tested with an Heinkel 111 bomber though was never taken into combat by this aircraft. A few special variants of the long-range Heinkel 177 bomber were equipped to carry the Fritz-X but it appears this combination never saw combat.

Fritz-X was first deployed on 21 July 1943 in a raid on Augusta harbor in Sicily. A number of additional attacks around Sicily and Messina followed, though no confirmed hits were made and it appears the Allies were unaware that the large bombs being dropped were radio-guided weapons. [RL 10/493: Tätigkeitsbericht über Einsatzperiode das K.G. 100 mit F.K. in der Zeit von 12.7.43 - 30.4.44. [Activity Report of Missions of KG 100 with Guided Weapons in the Period from 12.07.43 to 30.04.44.] ]

On 9 September, the "Luftwaffe" achieved their greatest success with the weapon. After the armistice with the Allies, the Italian fleet had steamed out from La Spezia and headed to Malta. To prevent the ships from falling into Allied hands, six Dornier Do 217 K-2s from the III. "Gruppe" of KG100 (III/KG100) took off, each carrying a single Fritz X. The Italian battleship "Roma", flagship of the Italian fleet, received two hits and one near miss, and sank after her magazines exploded. 1,255 men, including Admiral Carlo Bergamini, died. Her sister ship, "Italia", was also damaged but reached Malta.

The light cruiser "Savannah" was hit by Fritz-Xs at 1000 on 11 September 1943 during the invasion of Salerno and was forced to retire to the United States for repairs. A single Fritz-X passed through the roof of "C" turret and killed the turret crew and a damage control party when it exploded in the lower ammunition handling room. The blast tore a large hole in the ship's bottom, opened a seam in her side, and blew out all fires in her boiler rooms. "Savannah" lay dead in the water with the forecastle nearly awash and took 8 hours to relight boilers and get underway for Malta.

"Savannah's" sister ship, "Philadelphia", had been targeted earlier that same morning. While it is often believed the ship was hit by a Fritz X, in fact the bomb just missed the ship, exploding about 15 yards away. Damage was minimal. [See Barbara Tomblin's With "Utmost Spirit: Allied Naval Operations in the Mediterranean, 1942-45" (Lexington: The University Press of Kentucky, 2004), 273. Tomblin cites as her source the original action reports filed by the "Philadelphia" which clearly indicate the bomb missed. Also, had a Fritz X actually struck "Philadelphia", the ship would have severely damaged or sunk. The erroneous notion that "Philadelphia" was hit emerged from an article in "Proceedings" in 1976 by Charles Bogart and has been repeated since.]

The light cruiser HMS "Uganda" was hit by a Fritz-X off Salerno at 1440 on 13 September. The Fritz X passed through seven decks and exploded under her keel. All boiler fires were extinguished, 16 men were killed, and "Uganda" took on 1300 tons of water. "Uganda" was towed to Malta for repairs.

Two merchant ships may have been hit by Fritz X bombs at Salerno, though the evidence is uncertain. SS "Bushrod Washington" was hit by a glide bomb, either a Fritz-X or Hs 293, on 14 September while offloading a cargo of gasoline. [It remains uncertain today the exact cause of the loss of "Bushrod Washington". Most accounts credit the attack to an Hs 293 launched from II./KG 100, and certainly it is known from Luftwaffe records that II./KG 100 was active above Salerno around that time, flying nine missions from 9 September to 30 September, three of them during the day. Certainly eyewitness descriptions of the attack indicate that the side of the ship was blown out which is more consistent with a Hs 293 attack than a Fritz X attack. The situation if further confused because original reports, possibly contrived to avoid mention of the glide bombs in accordance with U.S. policy at the time, suggest two conventional 250-kg bombs dropped from dive bombers were responsible.] SS "James W. Marshall" was set afire by a conventional bomb, Hs 293 or Fritz-X on 15 September. [As with the "Bushrod Washington", the nature of the weapon that damaged "James W. Marshall" is uncertain. A witness aboard a ship nearby, Joseph A. Yannacci, attributes the attack to Ju 87 dive bombers, which did not carry glide bombs. While an attack with a Fritz-X cannot be ruled out, though there is at least an equal case to suggest that, if a glide bomb was involved, the culprit was an Hs 293 from II./KG 100. First, we do know from Luftwaffe records that II./KG 100, armed only with Hs 293 glide bombs, was active over Salerno that day. Second, it would be unusual for the heavy Fritz-X armor-piercing weapons of III./KG 100 to be employed against a simple cargo ship as this weapon was typically deployed against heavy cruisers and battleships. Third, the armored Fritz-X dropped from high altitude would probably have passed all of the way through the ship before exploding, in contrast to the damage reported for "James W. Marshall". Finally, not all of the Luftwaffe aircraft survived their missions that day, and the one glide-bomb carrier that failed to return on 15 September was from II./KG 100 (aircraft 6N + HP Wk.Nr. 5552 of 6./KG 100) and this unit was equipped with the Hs 293 rather than the Fritz X.] It survived to be towed back to England and used as part of the Mulberry harbour during the Battle of Normandy.

KG 100 scored another success with Fritz-X while the British battleship "Warspite" was providing gunfire support at Salerno on 16 September. One bomb penetrated six decks before exploding in number 4 boiler room. This explosion put out all fires and blew out the double bottom. A second Fritz-X near-missed "Warspite", holing her at the waterline. She took on a total of 5,000 tonnes of water and lost steam (and thus all power, both to the ship herself and to all her systems), but casualties were few. She was towed to Malta by tugs "Hopi" and "Moreno", then returned to Britain "via" Gibraltar and was out of action for near 9 months; she was never completely repaired, but returned to action to bombard Normandy in the invasion of Europe.

The last Fritz-X attack at Salerno again lightly damaged the light cruiser "Philadelphia" with two near misses on 17 September. [This attack is sometimes reported as taking place on 18 September. However, according to US Navy records, the cruiser "Philadelphia" departed Salerno the night of 17/18 September. Moreover, according to Lufwaffe records, III./KG 100, the Luftwaffe unit armed with the Fritz-X, flew its last mission on 17 September. ] Other ships damaged by Fritz-X included British sloop "Flores" and destroyer "Loyal".

The control system used for Fritz-X, known as "Kehl-Strassburg" (also used by the Hs 293), was susceptible to electronic countermeasures. After the initial attacks in August 1943 the Allies also went to considerable effort to develop devices which jammed the 48.2 MHz to 49.9 MHz radio link between the Kehl transmitter aboard the launching aircraft and the Strassburg receiver embedded in the Fritz-X. Early efforts by the U.S. Naval Research Laboratory produced the XCJ jamming transmitter installed aboard the destroyer escorts USS "Herbert C. Jones" and "Frederick C. Davis" in late September 1943, too late for Salerno. Unfortunately, the XCJ was ineffective because the frequencies selected for jamming were incorrect. This was updated in time for combat at Anzio with the XCJ-1 system, installed aboard two destroyer escorts above as well as destroyers USS "Woolsey", "Madison", "Hilary P. Jones" and "Lansdale". These six ships rotated service at Anzio, with three deployed at any time. This system met with some success, though because of its manual interface, it was cumbersome to use and easily overwhelmed if large numbers of weapons were deployed simultaneously.

In early 1944 the U.K. began to deploy its Type 650 transmitter which employed a different approach. This system jammed the Strassburg intermediate frequency receiver (3 MHz) and appears to have been quite successful, especially as the operator did not have to attempt to find which of the 18 Kehl/Strassburg command frequencies were in use and then manually tune the jamming transmitter to one of those frequences. This system automatically defeated the receiver regardless of which radio frequency had been selected for an individual Luftwaffe missile.

Following several intelligence coups, including a capture of an intact Hs 293 at Anzio and recovery of important components from a crashed He 177 on Corsica, the Allies were able to develop far more effective countermeasures, all in time for the invasions at Normandy and in Southern France. This included an updated XCJ-2 system from the Naval Research Laboratory (produced as the TX), the modified airborne AN/ARQ-8 Dinamate system from Harvard's Radio Research Laboratory, NRL's improved XCJ-3 model (produced as the CXGE), the Types MAS system produced by the Airborne Instruments Laboratory (at the time affiliated with the Radio Research laboratory), the British Type 651 and the Canadian Naval Jammer. Even more sophisticated jammers from NRL, designated XCK (to be produced as TY and designated TEA when combined with the upgraded XCJ-4) and XCL, were under development but were never deployed as the threat had evaporated before they could be put into service.

By the time of Normandy landings, a combination of Allied fighters, to keep bombers at bay, and ship-mounted jammers meant the Fritz-X had no significant effect on the invasion fleet. [Some accounts say the Norwegian destroyer "Svenner" was hit by Fritz-X at dawn on D-Day. This is highly unlikely as III./KG 100, the unit which carried the Fritz-X into combat, had largely migrated to the Hs 293 missile by that time for its anti-ship missions and the attack on "Svenner" occured before the first glide bombers launched their assaults on the Normandy beaches.]

Fritz-X is often incorrectly listed as having been responsible for the loss of the hospital ship HMHS "Newfoundland" at Salerno as well as the destroyer HMS "Janus" and the light cruiser HMS "Spartan" at Anzio. However, these ships were hit by Hs 293s, as clearly demonstrated by a careful analysis of "Luftwaffe" records regarding the deployment of III./KG 100, [RL 10/493: Tätigkeitsbericht über Einsatzperiode das K.G. 100 mit F.K. in der Zeit von 12.7.43 - 30.4.44. [Activity Report of Missions of KG 100 with Guided Weapons in the Period from 12.07.43 to 30.04.44.] ] the nature of the damage inflicted, [DNC 6/R.322: "Report by the Admiralty Department of Naval Construction: Board of Enquiry 9th February 1944 in Naples." This is the official report on the loss of "Spartan" and clearly identifies the Hs 293 as the weapon used; the nature of the damage, described in detail, is fully consistent with an Hs 293 and inconsistent with Fritz-X.] as well as reports from witnesses. [See for example Captain John Eric Wilson's first-hand account as presented in "Sinking of the Hospital Ship SS Newfoundland", "Newfoundland Times", September 1994, pp.9-15. The "Newfoundland Times" is the semi-annual publication of the HMS Newfoundland Association, formed by veterans of the cruiser (not hospital ship) HMS "Newfoundland".] (In the case of "Janus", either an Hs 293 or a conventional torpedo was responsible.)

The closest Allied equivalent to Fritz-X was Azon.

Operators

;flag|Germany|Nazi
*Luftwaffe

See also

* List of World War II guided missiles of Germany
* Kramer X4- Max Kramer's air-to-air guided missile
* Tarzon
* Gargoyle
* GB-4
* GB-8

References

External links

* [http://www.ausairpower.net/WW2-PGMs.html The Dawn of the Smart Bomb]
* [http://www.1jma.dk/articles/1jmaluftwaffegroundweapons.htm German guided weapons of World War II]
* [http://www.vectorsite.net/twbomb_04.html Allied & German guided weapons of World War II]
* [http://collections.nasm.si.edu/code/emuseum.asp?style=text&currentrecord=1&page=search&profile=objects&searchdesc=Ruhrstahl&quicksearch=Ruhrstahl&newvalues=1&newstyle=single&newcurrentrecord=1 Smithsonian National Air and Space Museum]
* [http://www.rafmuseum.org/cosford/collections/missiles/missile_info.cfm?missile_id=8 Ruhrstahl AG Fritz-X - Royal Air Force Museum, Cosford (UK)]