Guided German air to ground weapons in WW2
On special German WW2 Air to ground weapons
Text by 1JMA founder Friis
The early guided bombs and missiles.
Keywords: Guided Weapons, Fritx X, Hs 293 missile, Roma, Hagelkorn.
This article will deal mainly with the 2 major guided weapons used by the German Luftwaffe during the war. There is many other special air to ground weapons that are outside the scope of this work, but might find its way into other articles later.
Please note that I’m no expert on this field, so if you find any errors in this article, please do E-mail me.
The development of this guided bomb started pre war by Dr. Max Kramer, and tests were made with radio controlled spoilers fitted to 250 kg bombs. In 1940, the RLM got interested in Dr Kramers work, and The Ruhrstahl factories in Westfalen, in coordination with Dr Kramer, were ordered to make a guided free fall weapon system of the PC 1400 bomb for attacking ships.
Fritz X, as the weapon system was called had four centrally mounted plain cruciform fins, spanning 1,35 m. The Weapon was steered by means of electrical operated oscillating spoilers and by the rather complex tail structure. The weapon was roll stabilised by a gyroscope. In the rear section was the radio link for the control system. Like the Hs 293 missile described below there was also manufactured a wire guided system, but , like the Hs 293, the majority of weapons were radio guided. The control equipment could operate on 18 different channels, making launch of more then one weapon from a flight of planes possible without control interference
Like the Hs 293 the Fritz X was optically guided. There was a marker flare in the tail unit of the weapon. Using a joystick and a a Lofte 7D sight, the controller worked to keep the flare over the target. The maximum control of the weapon was about 500 meters to each side, to the initial aim of the launch had to be rather accurate. Compared to the free fall weapons of WW2, the Fritz X was accurate! A skilled operator could get 50% of the bombs with in a 15 m radius of the aiming point, and about 90% hit within 30 m radius. (Other sources say 60% hits within 4,6 meters radius)
The warhead could penetrate about 130 mm of armour before detonating. There was a micro delay fuse so the weapon detonated within the target. The explosive payload was 320 kg.
The weapon system did not work well when dropped below 5000 meters (other sources say 4000 meter) , and most operations was conducted above 6000 meters to help lessen the danger of AA fire.
This was particular important as the controlling plane had to keep flying level and reduce speed to keep the aim, so if it was within range of allied fighters or AA fire it was extremely exposed.
Testing of the weapon system started in spring 42, and a special unit, Erprobungs & lehrkommando 21 was formed in September 42 to test the weapon. Practice runs were made against old sunken target ships in the Baltic, 3 live drops pr. Aircraft crew. It was operational about the same time as the Hs 293 missile, and trough a more primitive weapon system than the missile, the Fritz X scored quite a few military successes. III/KG 100 was equipped with Fritz X mounting Doriners Ds 217 K2’s and started operation over the Mediterranean on 29 august 43.
The most famous is the sinking of the Italina Battleship Roma and the damaging of her sistership Italia on 9 September. Because of its success and fame, it will be described in detail.
The situation regarding the future faith of the still important Italian navy was tense during these autumn days. III/KG 100 was given the order to deal with the Italian navy “If it sails north, protect it, if it sails south, sink it”
On that day, KG 100 got the news that the Italian fleet had broken south. 3 Battleships, six cruisers and many small vessels were within hours of allied fighter cover. At 14.00 hours, 6 Do 217 took off from Istres, each carrying 2 Fritz X weapons and a full load of fuel. Lead by Oberlieutenant Heinrich Schmertz the bombers keeps low for about an hour before they started climbing to about 5500 meters. The Fleet group was sighted, and AA fire started rising. The Doriners kept level and reduced speed to 180 km/t. The Roma started turning. Schmdertz bomb aimer, Oscar Huhn steered a Fritz X bomb directly onto Romas front deck. Within 20 minutes the ship sank (one source claim the Roma was hit twice) Italia was damaged. Just 9 bombs dropped from high altitude had killed one battleship and damaged another! The attack on Roma killed 1254 sailors, including Admiral Bergamini.
The Luftwaffe, for resons of secrecy, claimed the hits were made by ordinary armour piercing bombs.
Importance of anti shipping weapons for the German war efford were increasing in the Mediterranean theatre, as the Italian fleet now was out of action on the Axis side.
Bombers carrying Fritx X bombs went into action again at Salerno, scoring several close hits and damaged the USS Savanah and several support vessels. The Cruisers HMS Uganda and HMS Warspite was also hit. The power of the Fritz X can be seen from the hit on the Warspite, 3 bombs were launched, 2 scored near misses, while the 3 penetrated 6 decks before exploding on and blowing trough the bottom of the ship. One Boiler rooms was destroyed, all steam was lost, steering was lost and armament and radar was out of function. The Warspite had to be towed to Malta for major repairs. The cruiser USS Philidelphia was also damaged and the destroyer HMS Janus was sunk.
On April 1944 X1 bombs were launched against England for the only time, against shipping targets at Plymouth, 15 Do 217’s attacked with guided bombs, but no important targets were destroyed
It was hoped guided weapons would provide a major advantage against the expected allied invasion in France, but Allied air superiority made the slow and level approach of the guiding aircraft impossible.
The work on the guided glider weapon against shipping started early in the war. The RLM urged for a weapon that would level out right at sea level(or just enter the water) but that was deemed too advanced since there was so little experience with guided weapons.
The first model build of the Hs 293 glider weapon was the HS 293 Vss, and examples of this was tested for control tests. It was designed in 1940. The same year, in july, the V3 design, still without any engine, was being tested. By the end of 1940 ,the Hs 293 A-0 had been produced with a underlsung rocket engine, giving the possibility of a low level release and still an acceptable gliding distance before contact with the target. The 18 of December a version was launched with success.
During the entire Hs 293 development program about 1900 weapons were build purely for testing and modifications. Some of these were modified for active service later.
The production model, Hs 293 A1 was a small glider with stubby wings. In the front was a 500m kg warhead with 295 kg of HE explosive. The warhead was thin walled and mainly good for light or non armoured targets as it lacked armour penetration capacity (unlike the Fritx X weapon) and in the rear of the fuselage was the controls: Aierons operated by electromagnets and an elevator operated by a electric motor. The Weapon was stabilized by a gyroscope that took control of the aerilions when no guidance signal came from the launch plane.Beneath the body was a Walter 109 507 B liquid rocket , that could provide 600 kg of trust for 10 seconds. This could boost the launch speed by about 200 km/h. This made the weapon clear the launch plane fast and made the visual controls possible.
After launch the bomber reduced speed about 25% to let the weapon get velar, this had the added advantage of keeping the plane further away from a targets AA envelope.
Aiming the weapon was line of sight. In the rear of the weapon was, for day operations,5 flare candles, and for night operations, flashing lamps. The operator in the launch plane could then, using a Joystick and radio control, guided the weapon towards the target. The control equipment could operate on 18 different channels, making launch of more then one weapon from a flight of planes possible without control interference. Although primitive compared to modern guided weapons, it was possible for this method to be fairly accurate, but demanded quite some skill from the operator.
The weapon was not accurate at gliding ranges below 3000 meters. Ranges for the weapons depended on launch attitude. At 1400 meters, it was 12 km, at 6000m meters, it was 16 km. The was no maximum attitude for launching, but the weapon was not effective if the dive was steeper than 30 degrees, as the speed then made the weapon uncontrollable. For all ranges, the guidance was dependent on good visibility of the target.
The radio system was moderated during the productions to render it more immune from jamming. A wire guidance system where a small wire was unwound from the rear of the missile was tested and about 100 weapons were modified to the 293 B standard with wire guidance.
A later and even more advanced control system was introduced on the 293 D model described later.
During 1941, Luftwaffe personnel was trained on the weapon system. Mass production of weapons started in January 1942. In September 42 the Lehr and Eprobungs commando 36 was formed to introduce the weapon in service and to work on tactics.
The weapons were first used in action on the 25 of August 1943, by II/ Kg 100 based at Cologne deploying the missile from their Doriner Do 217 E-5s bombers. The unit was formed in the spring of 43, and the Do 217’s were modified to carry a Hs 293 missile beneath each wing.
The first mission was an attack against Royal navy vessels in the Bay of Biscay. The attack damaged a corvette. 2 days later a more successful mission was flown, where the corvette Egret was sank after a missile hit and a destroyer was damaged.
On the 7 of September the group was transferred toIstres, to provide attacks against the allied invasion forces in the Mediterranean sea. Here the problems of the weapon system was shown, as it was dangerous to deploy the bombers when there was a heavy fighter cover, especially since the bomber guiding the missile could not make too large evasive manoeuvres and still hit the target, so II /KG 100 mainly flew might missions.
Another unit the II KG 40 was also deployed, using Heinkel He 177 A5’s against convoys in the Atlantic. Their first mission on the 21 November 43 was quite a failure due to bad weather. II KG 40 was transferred to the Mediterranean theatre, while III Kg 40 continued to use Hs 293 missiles against shipping from FW 200 C-3 Condors. These missions were kept at a low intensity, and they never became a major treat to allied shipping.
In the Mediterranean theatre there was some success, but at the 26 November, half of II/Kg 40 was destroyed during an attack on a convoy off the Algerian coast.
Hs 293 missiles were deployed against the Allied landing at Anzio (as did the Fritz X bombs) in January 44 , but allied fighter cover, radio jammers and smoke screens made the missiles a lot less effective. But the Cruiser HMS Spartan was hit by a missile and sank. (other sources claim the kill was made by a X1 guided bomb)
As with the Fris X bomb, much hope was given to the missiles use against shipping when the major allied Invasion of Europe came. But as shown before, the Bombers had a hard time performing when there was little or no Luftwaffe fighter cover, and the planes were either brought down or forced to abandon the target run before the missile struck home.
The missiles continued to see some use during the closing months of the war, the last attacks being carried out by a special unit of KG 200 that attacked bridges across the Oder with Do 217’s in april 45. (According to James Lucas, on his work on the KG 200, some or all of those attacks were actually carried out with 6 Mistrel combination aircraft weapon systems, were only 3 arrived at target)
An interesting development of the missile system was the Hs 293 D . It was a standard HS 293 A1 missile with an extended nose and fuselage center, build to carry Television equipment, thereby removing the need for the carrier plane to keep line of sight to the target. In the rear section of the missile was an antenna sending signals to the carrier plane. The television equipment, K11, was crude compared to todays guided weapons, 224 line pictures been screened at a frequency of 50 pictures a second. Test flight were carried out in 1944, but the development program never really took off. The TV guiding by Joystick required quite some skill from the operator, and for the program to work there needed to be a large amount of simulator training. Range for the TV signal was about 4 km.
There was also the 293 F model with a delta wing and no tail unit, and 2 schmidding SG 33 rocket units for power that gave 1855 kg of trust for 3,5 sec , the extent of progress on this type is unknown.
The 293 G model was designed for vertical attack, to gain some of the advantage the Fritz X weapon had for anti shipping warfare. Only 10 were produced.
The 293 H model were designed to be an anti air weapon against bomber formation, to be detonated inside or close to the bomber formations, both infrared proximity fuses and TV guidance was planned. There was even a 293 HV 5 version planned for the high speed Arado 234 twin engine Jet.
The Hs 295 was a redesign to carry a larger armour piercing warhead with 580 kg of explosives. No quantity production was started.
The Hs 293 was ain innovative weapon system, but it’s weaknesses when faced with bad weather or enemy fighter cover made it less of an treat than it could have been. Apart from the ships mentioned above, at least 5 other destroyers and numerous escort and transport ships were sunk by the Hs 293 missiles.
One can’t help but to speculate. Had these weapon systems been available earlier in the war, both from The Condors roaming the Atlantic and the Luftwaffe planes attacking the Malta Convoys it might have made a somewhat larger impact. But, like many other special german weapon systems, it was a case of too little and too late.
Still, it did show the shape of things to come, were guided Air to ground weapons became way more important. Today, guided missiles with TV cameras in the nose is on the cutting edge of airpower.
Other prototype weapon systems worked on this angle, Especially the Blohm & Voss Bv 246 Hagelkorn, that was a radio beam guided unpowered gliderbomb with a 435 kg warhead. (Not unlike later versions of the Allied gilderbombs) It was suggested that the radio guidance on this weapon could be “turned on” to the transmitter stations in Southern England that were providing navigation aids for the allied bomber fleets. More than 1000 were manufactured, and there was even planned versions for carrying chemical weapons, but none were deployed in active service.
J.R Smith & Anthony L. Kay: German Aircraft of the second world War
Alfred Price :Guided missile Genesis, in Flying Review international Nr 10 1964
Walt Boyne: Missiles against the Roma. in Flying Review international Nr 2 1968
Chris Bishop: Encyclopedia of weapons of world war 2”
The Oxford companion to world war 2
Roger Ford “Germany’s secret weapons in world war II”
James Lucas : “Kommando, German special forces of world war two”