German air-to-surface missiles 1939-45

Glider torpedoes

In the late 1930s, the Ministry of Aviation (Luftministerium) financed the development of torpedoes specially conditioned for aerial utilization. Particularly it was impulsed the model LT (Luft Torpedo or Aerial Torpedo) F5b, weighing 765 kilograms and fitted with multiple tail surfaces and possibility to adjust the orientation from the cockpit of the carrier aircraft before launching. Subsequently the company Blohm und Voss developed a series of torpedoes, starting by the L10 "Friedensengel" (Angel of Peace), which was launched from a bomber Junkers Ju 88A-4. This weapon was based in the F5b, but it had larger wings and stabilizers with vertical planes attached to their ends, which allowed to perform a sustained glide before immersing in the water with the adequate position and speed. They were delivered about 450 exemplars, prior to the serial production being dedicated to the more advanced model L11 "Schneewittchen" (White as Snow), of which only a few were finished. The series BT (Bomber Torpedo) corresponded to high-speed weapons that detached from the carrier aircraft - usually a fighter Fw 190F-8 - automatically, in the right moment of the dive towards the target, to later impact against the water and explode. The series models were the denominated BT 200, BT 400, BT 700 and BT 1400, whose numeration corresponds to their weight in kilograms.


Glider torpedo L10 Friedensengel.

Specifications for L10 Friedensengel



BV 143

This project seemed simple, but Blohm und Voss failed in its development. Developed from 1942, it was a glider torpedo which incorporated all the required elements to fulfill its mission. This is, it was not a torpedo to which a number of systems were superimposed, but the structure had been conceived to integrate the torpedo inside it. For such, the torpedo had been provided with wings and tail, ailerons, rudder and elevators, as well as an automatic pilot to keep the course towards the target. When the artifact approached the surface of the water, a hinged ventral probe of 2.1 meters in length was actuated by the waves, activating a rocket engine fed by petroleum and T-Stoff (hydrogen peroxide with oxyquinoline) stored in air-compressed deposits. The engine accelerated the missile, which traveled at sea level to hit the target ship just above the waterline. In 1943 were effectuated four tests of the BV 143, all of them in the sea, but due to the absence of a radioaltimeter that would keep at every moment the desired altitude - and which could have been developed -, the project was definitely cancelled.





BV 246

Initially designed as BV 226, the glider bomb "Hagelkorn" (Hailstone) was one of the many German missiles produced during the Second World War that were produced in large quantities, but rarely used. The main effort of the German war industry was dedicated to develop a stabilized and reliable glider bomb, telecommanded by a radio link that could not be interfered by the British - or even telecommanded by them -, whose dexterity in the utilization of electronic countermeasures constituted already a severe concern in 1942. In the project BV 246 the basic structure comprised a graceful aerodynamic fuselage, smaller than in the BV 143, cross-shaped tail with a large part of the vertical tail/rudder below the fuselage and amazing wings with a length/width ratio of 25.5:1, built with steel cores covered with nothing less than cement. Despite the high wingloading of 515 kilograms per square meter, the BV 246 flew well and had a gliding angle of 25:1. Because of that, if this missile had an adequate guidance system it would have been able to reach targets located at 209 kilometers of distance, if it were launched from an altitude of 10500 meters.

Numerous tests were carried from bombers He 111H-6, fighters Fw 190A and other platforms, using several command systems, among them radio and infrared, and something similar to the ILS, a system based in radio emissions that modern aircraft adopted for landing without visibility. The best method tested seemed to be the one of using the emissions from the Allied radars, but the Luftwaffe showed only a lukewarm interest. The production of the first series missiles - BV 246B-1 - started in one of the plants that the company had in Hamburg, in the late 1943, but in February 1944, when about 1100 units had been already produced and delivered, the entire program was cancelled. Finally, in later date, a large number of these missiles was launched from fighters Fw 190F-8 flying from Karlshagen. Some of the last BV 246 were fitted with the passive radar searcher "Radieschen" (Radish), suitable for attacking radar stations. One of the technical systems that the Germans wanted to put out of action was the long-range navigation system that allowed the Allied bombers to bomb with great precision targets inside Germany. The Luftwaffe managed to localize the transmitters that were emplaced in the south of England, but numerous air attacks to destroy them resulted unsuccessful because the Allied fighters defended fiercely such strategic points.





GT 1200

Henschel developed the GT 1200 for submarine attacks against surface ships. It had quite large wings, tail stabilizers and two rocket engines fed with solid fuel, one of them for submarine propulsion. On contact with the water the tail section would detach and a set of hydrodynamic surfaces would be used to direct this missile-torpedo underwater. The final version GT 1200C, shown in the picture, had 7.53 meters in length and a magnetic fuze that allowed it to explode directly beneath the target.



Zitteroschen

This project was probably the first supersonic missile fitted with wings, albeit the information existing about it is very scarce. Its origin is due to Doctor Voepl, who worked for Henschel and was supported by the Ministry of Aviation until October 1944. The weapon, whose German name means Torpedo Fish, had rather small triangular wings, of sharper angle in the trailing edge, and a vertical tail with stabilizers in its end. In the center section two rocket engines were attached simultaneously to the fuselage and the wings. Turning control was effectuated by means of Wagner bars, a system of spoiler type that allowed only for two positions and was placed after the trailing edge of each wing. An important part of the development was effectuated in wind tunnels at speeds of Mach 1.5. It was affirmed that this missile-torpedo was ready to be produced when the project was cancelled in October 1944.



Fritz X

Also denominated FX-1400 in general and, in particular, X-1 by the company that developed it and PC 1400X by the Ministry of Aviation, this weapon system has been one of the greatest missiles in History and one of the few that achieved significative results in wartime. It was undoubtely the king of the X series of missiles conceived before the war by Doctor Max Kramer and the DVL (Deutsche Versuchsanstalt fur Lufthart or German Institute of Aeronautic Investigations). It could be directed from distance in both axes (yaw and pitch or azimut and elevation) by means of spoilers, instead of conventional hinged surfaces. Kramer directed exhaustive tests of the artifact and experiments in wind tunnels, after which, in 1938-40, and with support from the Ministry of Aviation, were made the first test flights from Berlin-Adlershof, by using a command via radio link of a completely new type of tail to maneuver the spoilers and with a 250-kilogram warhead. In 1940, and despite of the lack of interest shown by the High Staff of the Luftwaffe in any long-term project - because of the thinking that Germany had the war already won -, it was allowed to the DVL to intensify the works about missiles by means of several projects. One of them, designated PC 1400X, was selected to be fully developed, because it seemed simple and suitable for the offensive strategy carried by Germany in that moment of the war.

The Fritz X was a 1400-kilogram piercing bomb, fitted with an enlarged version of the new type of tail developed in the tests of previous years. A gyroscope for vertical reference maneuvered the spoilers of the tail to stabilize the weapon in roll, in such way that the large stabilizator and the small drifts could operate in the correct direction. In the thicker part of each surface there was a solenoid that maneuvered with four spoilers of the stabilizer and two of the drifts. Surrounding the tail ensemble, an annular wing with twelve faces limited terminal speed. Around the gravity center, in a somewhat forwarded position in respect of the center of the fuselage, the missile had four fixed wings. Parallely with the development of the Fritz X, the Ministry of Aviation had financed a growing number of projects for radio communications and command links. The chosen among these last ones to equip the Fritz X was the type Kehl/Strassburg, which comprised the transmitter Kehl in the launching aircraft and the Strassbourg receiver in the missile. The main contract for the serial production was awarded to Ruhrstahl AG, starting the deliveries of the preseries model PC 1400X-O in February 1942.

The tests effectuated from Karlshagen were discontinued due to the frequent presence of clouds. In April 1942 the tests were retaken in Foggia (southern Italy) and great progress was made. The experimentation tunnel of the DVL solved an unexpected problem that emerged because there were spoilers that were blocked preventing so the guidance of the missile. Solved this problem, half of the preseries missiles impacted in a radius of five meters around the target. Bombers Heinkel He 111H-6 were used as carriers, but they resulted unsuitable for such a large missile, and because of this, for real combat actions were mainly used more modern bombers of the types Do 217K-2 and He 177A-5/R2, specially conditioned. After exhaustive trials and many trainings to set a doctrine of utilization - carried out mainly over the Baltic Sea by the Lehr-und-Erprobungskommando 36, which did the same with the missile Hs 293 -, the group III/KG 100, equipped with bombers Do 217K-2, was ready to enter action in Istres (southern France) in July 1943, under command from Major Bernhard Jope.

The 29th August 1943, the Fritz X took part for the first time in a war action, but its most famous intervention happened the 9th September, when the Italian Fleet departed from La Spezia to join the Allies shortly after the Italian Armistice, becoming so the perfect target for the missile. The unit commanded by Jope took by surprise the Italian Fleet in the Strait of Bonifacio - which separates Corsica and Sardinia - and concentrated the attacks upon the two largest battleships. The Roma received two direct hits, heeled and sank. The Italia was hit as well, leaking 800 tonnes of water, but, despite very heeled, she managed to reach Malta. During the following week, the III/KG 100 harassed the Allied fleet that covered the landings at Salerno, south of Naples. The Fritz X caused so severe damages to the British battleship Warspite that this one had to withdrawn towards Malta at reduced speed, remaining under rapairs during one year; they were sunk the cruiser Spartan, the destroyer Janus and many cargo ships, and severely damaged a number of cruisers. The German aircraft launched their missiles from altitudes above 5000 meters, out of range for the anti-aircraft batteries. The only response against the Fritz X was a better escort from fighters, which eventually caused the withdrawn of the III/KG 100.

When the program was discontinued in December 1944 about 1386 missiles had been delivered, much less than the 750 monthly units that had been planned. The Fritz X ended its operative career being used against land targets. For example, against the bridges laid by the Soviets over the Oder in April 1945, in a desperate effort for preventing the fall of Berlin. Of this missile existed, in the end, many versions fitted with different guidance systems, warheads and general configuration. Being the Fritz X such an effective air-to-surface missile, able to sink battleships displacing 46000 tonnes, such as the Roma, it seems strange that the Luftwaffe, who had them available since the summer 1943, had not launched thousands of them against the Allied forces.


Scheme of the FX-1400 missile, in which can be seen the armored piercing ogive and the warhead containing 300 kilograms of Amatol. Unlike modern missiles, the FX-1400 had such strong ogive because it was intended to perforate the thick armor of a battleship. The success achieved with the sinking of the battleship Rome led to the construction of versions weighing 2500 kilograms, Fritz X-5 and Fritz X-6, being built 100 units of each.



Hs 293

The company Henschel Flugzeugwerke was constituted in 1933 as the aeronautic subsidiary of the large corporation of the same name based in Kassel and dedicated to the manufacture of trucks and locomotives. That new company was the first organization in the world that was dedicated to the massive production of missiles. The series Hs 293 was the most prolific and varied in the history of the first missiles and large quantities of versions suitable to every type of target were built. The company had entered the business in 1938 along with Schwartz, the manufacturer of propellers, and many other industrial societies, all supported by the German Institute of Aeronautic Investigations. In January 1940, Doctor Herbert A. Wagner left the company Junkers to lead the team working in missile projects for Henschel. The works started with an air-to-surface missile that should be able to travel at sea level. The project was denominated probably Hs 291 and abandoned for resulting excessively difficult. Instead, in July 1940, it was started the design of the Hs 293, conceived as a glider bomb with airplane configuration. It was based in the 500-kilogram general- purpose bomb SC 500, to which were attached wings and a tail made of light alloys, with ailerons actuated by a solenoid and elevators actuated by an electric jack. A system of sensors, which measured the dynamic pressure (varying with the altitude and speed of the missile), modified the movement of the elevators to minimize the effect of lack of precision in the angle used.

The first missiles, of the model Hs 293 V2, were launched over Karlshagen around May 1940. In July, these were followed by the model Hs 293 V3, provided already with the definitive telecommand, produced by Kehl/Strassburg. In December 1940 tests were carried on the pre-series model Hs 293A-O, provided with a gondola hanged in ventral position, which contained a rocket engine Walter 109- 507B. This one consumed a composite of T-Stoff (hydrogen peroxide unsolved in water) and Z-Stoff (aqueous solution of calcium - or sometimes sodium - permanganate), which was delivered from the deposits by compressed air. The rocket engine provided during 10 seconds a thrust of 600 kilograms, for fastly driving the missile forward, in a position from where it could be easily seen by the operator placed aboard the launching aircraft. Although at least a hundred of missiles were tested with a control system by cable Dortmund/Duisburg - achieving ranges of even 30 kilometers -, the normalized control system was a radio link. The device had 18 channels in the band from 48 to 50 megahertz, so up to 18 missiles could be guided simultaneously without interfering each other.


The operator of missiles, located aboard a bomber He 111H-12, commands a Hs 293A-1 by means of a command lever and a radio-transmitter Kehl. The versions guided by cable were provided with a similar control lever. The Hs 293 became a successful design and the first on the series of rocket-propelled, radio-commanded bombs built by Henschel. Its warhead contained 550 kilograms of high explosive and the propulsion was given by a rocket engine Walter with a burning time of just 10 seconds. Once the missile was launched, and after the shutdown of the engine, it followed its course towards the target guided by the radio system. Many models fitted with different control systems and rocket engines and countless experimental devices were built. Still, despite this dispersion, circa 12000 exemplars were produced. Launched from the bomber Do 217, these missiles were frequently used during 1942-43 against Allied ships in the Gulf of Biscay and in the Mediterranean.

The first aircraft that carried this missile was the twin-engined bomber Dornier Do 217E-5 (also other versions with launching equipment Rustsatze), which equipped the special unit Edko 36 for performing trials on the Baltic, in July 1943. With the same aircraft, the missile entered service with the operative group II/KG 100, which was deployed in Cognac (southwest of France) in the summer 1943. The 27th August this unit sank the British corvette Egret, the first vessel in History destroyed by a missile launched from the air. In later dates, numerous vessels were sank as well by the Hs 293A-1, including four British destroyers and a Greek one. The method employed by the Luftwaffe consisted of keeping the missile hot in flight, by means of hot air delivered through a duct by the launching aircraft, generally a bomber He 111, He 177, Do 217 or Fw 200, or rarely of different model. The sparkles in the tail allowed the guidance system to be operative either at daytime or nighttime. The operator controlled the missile by performing a trajectory composed of a series of arcs, by means of a two-axled command lever, placed in one of the flanks on the fore compartment of the bomber. In the vicinity of the target and based on the diving angle, guidance became more difficult. The speed of the missile oscillated between 435 and 900 kilometers/hour. A large number of the attacks performed with the Hs 293 took place in the Italo-Mediterranean theater, albeit a special KG 100 unit was reorganized in April 1945 for attacking the bridges laid by the Red Army in the Oder. Production reached several thousands of units and a minimum of 2300 were launched.

The original version was the Hs 293A-1; it had a length of 3.82 meters, a diameter of 0.47 meters and a wingspan of 3.1 meters, with a weight of 1045 kilograms in the moment of being launched and a maximum range of 18 kilometers. The version Hs 293B was equipped with guidance system by cable. The version Hs 293C had a conical fuselage intended for submarine attacks and it gave pass to the variant Hs 294, a powerful missile-torpedo fitted with two rockets of which some hundreds of units were built. The version Hs 293D was a daring attempt of installing a television-based guidance system, and the very Herbert A. Wagner guided many of the about 70 missiles launched for testing. The limited range of the television/radio system (about four kilometers) led to the adoption of a cable-based guidance system. In the tips of the wings of the missile cones were installed for decreasing the speed, to prevent the breaking of the cable. The version Hs 293F had a delta shape and two engines, built with non-strategical materials due to the scarcity suffered by Germany during the last years of the conflict. The version Hs 293G was destined to be used in very pronounced diving angles, while the Hs 293H was an anti-aircraft missile intended to break the bomber formations of the USAAF 8th Air Force. The variant Hs 295, fitted with two engines, had a piercing warhead and the Hs 296 combined this warhead with the structure of the Hs 294 and the guidance system of the Hs 293.


Production exemplar of Hs 293A-1. This missile was rather effective when employed against unarmored targets.


The Hs 293D, equipped with a television-based guidance system. The Hs 293 was soon rendered useless by the Allies, who by means of special devices, interfered in the radio-based control system. Because of this the Hs 293 was retired from the battlefield in 1944.

Specifications for Hs 293A-1



Hs 294

The Hs 294 was very similar to the Hs 293, but it was built with a special nose that allowed it to make contact with the surface of the sea without exploding. Once on the water it was able to follow its course towards the target, like a normal torpedo. Its construction started in 1940 and during subsequent years it was tested many times; however there is no evidence that it were used against the Allies, probably because these were able to perturbate the radio command system. For eliminating this problem many missiles were fitted with anti-interference devices while others were equipped with small cameras located in the nose, allowing to see "in first person" where the missile was heading. The version Hs 294B adopted the guidance system by cable removing so the risk of interferences.



Rocket bomb Kurt

Bouncing bombs were a special type designed to bounce on the surface of the sea towards a target in a calculated manner to avoid obstacles such as torpedo nets, and to allow to predetermine their speed on arrival at the target and the timing of their detonation, similarly as depth charges do underwater. After the attacks carried out by the Royal Air Force on German dams in May 1943, using a specially developed "bouncing bomb", the German discovered one of such bombs that had failed to explode. Subsequently, they developed a 385-kilogram version of the bouncing bomb, codenamed Kurt. However, the importance of backspin was not initially understood and, during the trials, these bombs proved to be dangerous to the delivering planes - Focke-Wulf Fw 190 - as the bombs matched the speed at which they were dropped. Then the Germans attempted to rectify this by fitting the bombs with booster rockets, but these attempts were ultimately a failure, since the impulse provided by the rocket affected precision negatively, and the project was discontinued in November 1944.



Mistel

The concept of launching an aircraft from above or beneath another aircraft can be traced back to the first times of aviation. In 1941 the idea was proposed again by Siegfried Holzbauer, test pilot from Junkers, who suggested it to the Ministry of Aviation as means to give an additional - and definitive - use to bombers Ju 88 that suffered from attrition. Holzbauer imagined that such aircraft could be reconverted into missiles, transporting large explosive charges fitted with multiple fuzes, which could be directed towards their targets by means of a fighter coupled above. Once the bomber were launched, the pilot of the fighter could direct its trajectory by means of a radio link. This idea was initially refused, for in 1941 the Germans were convinced that they had the war in their hands. But one year later, the investigations center DFS effectuated viability trials, by using a transport glider DFS 230 hanging from a lighter aircraft - Kl 35 or Fw 56 -. This experiment was repeated with a fighter Me Bf 109E as transporter and this made the Ministry of Aviation to look again to the idea from Holzbauer. In 1943 it was made the first order of what was definitely called Mistel (Mistletoe).

The first conversion started to fly in July 1943, being formed by a Ju 88A-4 and a Me Bf 109F. The fighter, with its gear landing retracted, was supported by an ensemble of stems under its center fuselage and a very thin stem in the rear. The launching system consisted in the pilot releasing the rear stem, which was turned rearwards over a joint in the fuselage of the bomber. Then, this movement activated an electric mechanism that detached the main stems. After demonstrating that the invention worked, 15 additional conversions were ordered, which were codenamed Beethoven. Tests carried out with shaped-charge explosives installed in a fuselage of the size of a bomber Ju 88, against the French battleship Ocean, resulted encouraging and in later tests it was achieved to open a breach in a thickness of 18.3 meters of reinforced concrete. Four organizations - Junkers, DFS, Patin and Askania - developed then an operative command system for the Mistel. During takeoff and in the event of emergency - for example, in case of being intercepted by enemy fighters - the pilot could maneuver the flight surfaces of the fighter and the ones of the bomber simultaneously. Generally, he would only maneuver his own aircraft and use said connection only to adjust the elevators of the bomber or the rudder and ailerons. Regarding the Ju 88, this one suffered some changes in its structure, including a redesign in the center section of the fuselage. The first operative version was denominated Mistel 1 and it was composed of a fighter Me Bf 109F and a modified bomber Ju 88A-4, with the space for the crew replaced by a 3500-kilogram warhead.

The Mistel 1 was used for the first time by the II/KG 101, from Saint Dizier, in France. This unit performed nocturnal attacks against the Allied naval force during the landings in Normandy in June 1944, in the mouth of the Seine. Several ships were hit but none was sunk. Still, it was ordered the urgent conversion of 75 night fighters Ju 88G, to which was added a third wheel in the landing gear to avoid blowouts in the tires, which had caused some accidents during landings because the load exceeded the limits set for the Ju 88. In the early 1945 it was constituted a force composed of about 100 Mistel, being almost all of them of the version Mistel 2 fitted with the Ju 88G, but with a growing number of Mistel 3C. This last version reflected a radical change of doctrine. The lower component was no longer a bomber discarded for operative usage, but an artifact directly built to serve as missile. Said component had a longer fuselage and received the designation Ju 88G-10 or H-4. The fighter acting as upper component was an Fw 190A-8, fitted with external fuel tanks. To increase operational range even further, during the travel towards the objective the fighter used the 95-octane fuel carried by the Mistel itself and after releasing the missile it returned to base with its own 87-octane fuel. Usually, the pilot did not bother to guide the missile by means of the radio link and he just placed the Mistel in line with the target just before releasing it.

The approximated method to attack with the Mistel was the following: the fighter transporting the Mistel would fly horizontally towards the target ship at an altitude of 100 meters to avoid being detected; at a distance of 6 kilometers from the target the aircraft would start to ascend to an altitude of 800 meters, which would reach at a distance of 4 kilometers from the target, and then continue flying horizontally; at a distance of 2.4 kilometers from the target the aircraft would start a dive with an angle of 15 degrees; and, finally, at a distance of 1.6 kilometers from the target, the aircraft would release the Mistel after aligning it with the target, being kept the missile in course by an automatic pilot. About 250 Mistel were built or reconverted from bombers, but the projected mission "Eisenhammer" (Iron Hammer), intended to neutralize strategic points in the Soviet Union, never happened. In the last weeks of the war were made new combinations of Mistel, which included the formulas: Ju 88G-7 and Ta 152H; Ta 154 and Fw 190; Ar 234 and Fi 103; Do 217K and DFS 228. There was no time to develop new projects, such as the combinations Ju 287 and Me 262 or Ar 234C/He 162 and Ar E-377.

Categories: Missiles - World War Two - 20th Century - [General] - [General]

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Article submitted: 2015-01-29