German anti-aircraft missiles 1940-45

It is not much what is known about the Hecht, the German pioneer of surface-to-air missiles developed by Rheinmetall-Borsig, except that its name means "pike", its length was 2.5 meters, its diameter was 0.381 meters, its wingspan was 0.95 meters and its launching weight was 140 kilograms. It could have been a contraption exclusively conceived for investigation and in 1941 it was replaced by the F 55 Feuerlilie.

F 55 Feuerlilie (Fire Lily)

The history of this missile started as an investigation project sponsored by the Ministry of Aviation and following the aerodynamic principles from the Institute of Aerial Investigations, with growing expectatives towards a special anti-aircraft missile. The development program was effectuated with three different sizes. The Feuerlilie 5 had a diameter of only five centimeters and in the late 1941 it was superseded by the F 25 (which had a diameter of 25 centimeters), project which was awarded to Rheinmetall in 1942. After a long trials program, carried out between May and September 1944, this contraption of high subsonic speed (840 kilometers/hour) was superseded by the F 55 (which had a diameter of 55 centimeters and hence a much larger size), fitted with anautomatic pilot and radio-controlled guidance system. A rocket engine designed by Doctor Konrad, which used as fuel a mixture of R-Stoff and S-Stoff (respective mixtures of xylidine-triethylamine and nitric acid at 95 percent and sulfuric acid at 5 percent), was still unavailable and because of this it was used instead the Rheinmetall 109-515 engine fed with diglycol, which was much less powerful.

The original engine should have provided a thrust of 6350 kilograms during seven seconds and because of its absence all of the prestations expected could not be achieved. The structural design of the F 55 was rather simple; it had a cylindrical body with an ogival shape in the fore section, while the rear section was narrowed as well but truncated to serve as a single exhaust. The rear section, in a length equivalent to a third part of the body, had attached two large and strongly angled fins, one to each side, fitted with pitch rudders. In turn, each of the fins had perpendicularly attached to its end a smaller tail fitted with yaw rudders. Despite being so simple, the F 55 looked much more like a missile than its predecessor F 25, which curiously had been built with similar appearance than that of a turbojet fighter from the 1960s, with two swept wings in the center of the body and a vertical tail in the upper rear which had attached two horizontal stabilizers. Surprisingly, the F 55 program survived nearly until the surrender of Germany but its operative employment was never attempted.





Hs 117 Schmetterling (Butterfly)

This anti-aircraft missile was closer than any other to be operatively used. Its history began as one of the studies for anti-aircraft missiles carried out by Professor Wagner in the Henschel aeronautical company, in 1941, with the denomination Hs 297. Two years had to pass until the Ministry of Aviation showed interest about the project. In that time the Allied offensive of air bombings over Germany was increasingly intense, and it was signed a contract for the development of the missile, whose designation was changed to Hs 117. Conceived solely for interceptions within visual range, this missile was initially installed in a modified mounting of the Flak 18 37-millimeter anti-aircraft cannon. The target had to be visible to the operator, which in the practice constituted a great limitation, since reaction time was too long for being used against low-flying aircraft.

To make an estimation of the future position of the target it was adopted the normalized fire control calculator used in the conventional anti-aircraft defense. The missile required two operators; one of them looked through a 10x magnification optical sight while the other aligned the launcher by means of a control stick. The control of the trajectory was kept by the ground operator via a Kehl/Strassburg radio command system, which actuated on Wagner aerodynamic deflectors installed in the wings of the missile. Precision was notable, for the missile could hit an area of 7.5 meters in diameter at a distance of 15 kilometers. When launched, the missile accelerated its speed, reaching 1100 kilometers/hour in only four seconds. This impulse was given by two Schmidding 109-553 rocket engines fed with diglycol, which were placed one on each side of the body of the missile, being automatically detached after having depleted the fuel load, being so decreased the weight of the missile to 260 kilograms when it started to cruise.

Subsequently a lift engine would be started, generally a BMW 109-558, able to provide a thrust of 375 kilograms at sea level. This rocket engine was fed by a mixture of R-Stoff and SV-Stoff, and it kept airspeed at 864 kilometers/hour by regulating its thrust. The body of the missile was fitted with two swept wings in the central section and four tails in the rear section. Due to the absence of a proximity fuze, the 25-kilogram explosive charge was detonated by a radio command operating in a frequency different to that used to guide the missile. If the target aircraft flew at high altitude it was virtually impossible to make an estimation of the most timely moment to detonate the charge. The warhead was installed in the right part of the nose while a pinwheel generator occupied the left part. Hence, the nose had an asymmetric design, in resemblance to that of the air-to-air missile Hs 298.

The trials of the Hs 117 started in Karlshagen in May 1944. When in December it was authorized the beginning of the serial production, 59 launchings had been effectuated from land and a number of exemplars had been launched from Heinkel He 111 heavy bombers. A total of 34 launchings were failures. In the late 1944 it was decided to equip the launching platform with Wurzburg radars and Mannheim Riese screens, to grant operativity to the missile during night and bad weather conditions. It was tested as well a Fuchs proximity fuze. It was intended to achieve a monthly production of 150 units in March 1945, which should have reached 3000 in November, while the initial number of launching sites should have been 60. None of them, however, entered action, even if from September 1944 the unit of anti-aircraft investigations of the Luftwaffe (LET 700) carried out diverse tests and redacted the training manual for the operators. A supersonic version of this missile did not reach completion either. On the other hand, the designation Hs 117H corresponds to an air-to-air missile which was tested from a Dornier Do 217 bomber.





Rheintochter (Daughter of the Rhine)

The Rheintochter was a large and ambitious anti-aircraft missile developed in two different configurations: Rheintochter I for the Army (Heer), from November 1942, and Rheintochter III for the Aviation (Luftwaffe, responsible of the anti-aircraft defense), during the last year of the war. The number II belonged to an irrelevant transition model. The Rheintochter I was a remarkable creation for its time, with a large accelerator engine in tandem that provided a thrust of 75000 kilograms during 0.6 seconds, with four strongly angled fins, six fixed swept wings, four movable control surfaces in the nose and a lift engine that provided a thrust of 4000 kilograms during ten seconds, with the exhaust ducts placed between each pair of wings. The Rheintochter I used as launching platform a modified carriage of the Flak 18/36 88-millimeter anti-aircraft cannon. The control of the trajectory was made via radio command. By means of a control stick and while observing the tracing flares placed in opposite position in two of the wings of the missile, the operator had to keep the missile in his line of sight while it flew towards the objective. The first launching took place in August 1943 in Libau, in the Baltic coast. The program Rheintochter I was abandoned in December 1944, when 82 launchings had been carried out, since this missile could not match the prestations of altitude achieved by the Enzian or the Schmetterling.

Much better prestations were achieved with the Rheintochter III, which had laterally installed accelerator engines. This was a two-phase missile propelled by two engines, one fed with solid fuel and another fed with liquid fuel. It should have had a lift engine projected by Doctor Konrad, whose combustion time was 43 seconds, but five of the six missiles which had flown when the project ended in December 1944 used a solid-fuel lift engine. The guidance system remained unchanged: the ground operator had to manually maneuver the missile until reaching the enemy bomber formation, and then he could choose to detonate the explosive charge or to entrust this function to an acoustic sensor. A variant of the Rheintochter program was intended for a piloted version. The pilot, accommodated in the nose of the missile, had to direct it towards the enemy formation by following the instructions received from the ground base and then, once the missile were "locked" upon the enemy, get out of it by parachuting. This project, however, remained very delayed in respect of the conventional missile, being the flight tests initiated in the early 1945. In any case, despite its primitive guidance system, the Rheintochter program constituted an important technical legacy for the subsequent generations of missiles.


The Rheintochter I, projected by Rheinmetall, was an anti-aircraft missile fitted with a 150-kilogram warhead. When the construction was started, the Ministry of Aviation (Luftministerium) requested the missile to have a higher effective ceiling, so the investigations had to be restarted.



Wasserfall (Waterfall)

Albeit anti-aircraft missiles belonged to the domain of the Luftwaffe, one of the most promising contraptions of this type was developed in Peenemunde, whose facilities belonged to the Heer. This was so because only in Peenemunde there was experience with rockets that reached speeds as high as Mach 3. To divert attention about such secret projects, the facilities at Peenemunde had received the official name of Electromechanical Factory Investigation Department. There, in December 1942, it was started the development and construction of a real-size model of the Wasserfall, whose aerodynamic profile was based in previous studies made for the A-4 surface-to-surface missile (perhaps better known as V-2) and its derivative A-7, a project of much larger size fitted with wings. Like these, the Wasserfall was launched in vertical position from a platform and it had to take off impulsed by the relatively modest thrust generated by its lift rocket engine.

Flight control was effectuated by means of radio command which actuated in graphite deflectors, whose movement directed the exhaust jet produced by the engine. The possibility of using these deflectors ended 15 seconds after the launching, so the control system actuated as well in rudders on the four rear tails, capable of performing maneuvers with an acceleration of up to 12 g-force (modern jet fighters do not exceed 9 g-force), once the speed of the missile had exceeded 1350 kilometers/hour. The operator that directed the missile from the ground had to attend a complex screen displaying two lines of sight, both in two dimensions, within the denominated Rheinland system, in which the target and the missile were tracked by different radars. The operator had to manage the control system of the missile to make both lines of sight coincident, however he lacked any information about range to know when to push the button that would detonate the explosive charge. Due to this a proximity fuze had to be fitted, which triggered the explosion at not less than ten meters from the target. To achieve this the missile was fitted with an infrared sensor which was able to "sense" the heat generated by the engines of a heavy bomber from a distance of 3-4 kilometers.

The heavy payload included 145 kilograms of explosive and other 90 kilograms for the self-destruction system which had been prepared for the event of the missile missing its target. Doctor Thiel, chief projectist of the engine for the Wasserfall, died in the attack that the Royal Air Force effectuated upon Peenemunde in August 1943, and it was M. Schilling who took charge of the propulsion system P IX, experimenting with many different mixtures of the fuels usually used in the propulsion of the German rockets of that time. The thrust provided by the rocket engine at sea level was 8000 kilograms during 40 seconds. The displacement of the gravity center of the missile as the fuel was being consumed was one of the problems which had to be solved. After overcoming numerous difficulties, a Wasserfall was sent in January 1944 to Greifswalder Oie, a Baltic isle next to Peenemunde, for being tested, but the missile was unable to fly. However the second missile tested managed to fly the 29th February, reaching an altitude of 10500 meters, a third part of what was intended. When the program was abandoned, the 6th February 1945, at least 35 missiles had been launched (being the real number almost certainly 51), besides a high number of aerial launchings and some prototypes built in reduced scale.

In conclusion, a third part of the launchings had been deemed unsatisfactory. The cessation of the program was due to constant design changes, to a number of minor accidents and to the lack of basic technology. Besides, the program had been delayed because the development program of the A-4 had higher priority. In the date in which such decision was taken, the series missile, designated C2-8/45, had been completely defined and it had been proposed to produce 900 units per month in an underground factory that had to be constructed in Bleichrode. The Wasserfall had been proposed as a weapon for the defense of large cities; the plan provided the installation of 200 batteries disseminated in three large zones, equidistant 80 kilometers each other. Subsequent plans provided 300 batteries for being able to defend the entire metropolitan territory. For carrying out these plans successfully, 500 of these missiles would have to be built every month.






Test launching of a Wasserfall in Greiswalder Oie, in 1944. The size of the missile was similar to that of the A-4 surface-to-surface missile. The development of an anti-aircraft missile posed new challenges for the German scientists.



E-4 Enzian (Gentian)

Preceded by a series of Flak-Rakete (Anti-Aircraft Rocket) test vehicles, the Enzian was a subsonic anti-aircraft missile made of wood, built by Messerschmitt and initially projected by George Madelung, albeit the program was later directed by Doctor Hermann Wurster, in Oberammergau. The contraption used the basic layout of the Messerschmitt Me 163 rocket-propelled fighter aircraft and the control was effectuated by means of ailerons. The Enzian was launched from a modified mounting of the Flak 18/36 88-millimeter anti-aircraft cannon. Four Schmidding 109-553 rocket engines fed with solid fuel provided a thrust of 7000 kilograms during four seconds. The trial vehicles E-1, E-2 and E-3 were fitted with the Walter R I 210B lift engine which was fed by a mixture of diverse liquid fuels, and worked during 70 seconds keeping the speed of the missile around Mach 0.85. At least ten of these artifacts flew in Karlshagen from April 1944. The subsequent vehicles had a guidance system through Kehl/Strassburg or Kogge/Brigg radio command, but imprecise thrust axes often caused loss of control.

The operative prototype E-4 - which was an E-3B of larger size - was to be fitted with an explosive charge which would weigh 300 kilograms (including the self-destruction system) and would have several proximity fuzes. Several systems had been projected for autonomous guidance, among them an infrared system called Madrid, a radar system called Moritz and an acoustic system called Archimedes. None of these systems was further developed, as happened as well with the Walter lift engine, so the 28 test flights of the E-4 were effectuated with a DVK engine of similar prestations than that of the prototype E-3B. In total about 60 Enzian E-3B and E-4 were built, but when the program succumbed to the generalized screening which was carried in January 1945, the Enzian still had to run a long path to be apt to enter service. In February, Messerschmitt tried to support the prototype E-5, which was a slender supersonic version with swept wings, a lighter explosive charge and an improved lift engine, but the Nazi Germany was living its last weeks. On the other hand, the denominated E-6 was a small wire-guided anti-tank version, which probably did not reach theconstruction phase.




One of the first Enzian placed in its launching platform. The photograph was taken in April or May 1944. The structure of the missile was based in the Me 163 Komet rocket-propelled fighter.



X-4

This is one of the most historically important missiles, for it not only established air-to-air missiles as an effective reality, but also demonstrated the reliability and immunity against electronic countermeasures of wire-guided systems, which would later prevail in anti-tank missiles and many other tactical weapons. The design of the X-4 was started by Doctor Max Kramer of Ruhrstahl in the early 1943, receiving the designation RK 344 from the German Air Ministry. Discarding the shape of an aircraft, Kramer choose the configuration of the Fritz-X air-to-surface missile (developed by him as well), with cross-shaped wings placed around the gravity center and cross-shaped fins with control rudders placed in the tail of the missile, turned 45 degrees in respect of the wings. The swept wings reduced aerodynamical drag while the missile was hanged on a turbojet aircraft, and allowed to briefly reach speeds above Mach 1 after the ignition of the BMW 548 rocket engine, which used the Salber and Tonka hypergolic propellants, injected by compressed air applied to a loose piston which slided along a spiral fuel deposit. This complex feeding system sought to ensure the consumption of all the fuel even if the missile effectuated violent maneuvers.

The X-4 was launched at the same level that the target, preferably from behind and from a distance over 1.5 kilometers. The pilot observed the target and kept the missile aligned with it by means of a small Dusseldorf-Petmold control stick, which used direct current for roll and polarity reversal for pitch. Small fins in the wings caused the missile to slowly rotate and an automatic pilot sent the proper instructions to the tail rudders in accordance with the signals transmitted through two wires, which unrolled on coils located in the ends of two of the wings. The warhead, which carried 20 kilograms of explosive, had acoustic Kranich or Meise proximity fuzes (in 1945 it was started the Pudel program to attempt that the X-4 acoustically orientated itself against the target). At the end of 1944 about 1300 of these missiles had been produced, having being tested hundreds of them, the largest part of them with Schmidoling solid-fuel rocket engines. The first launching in the Karlshagen test field was effectuated the 11th August 1944 from a Focke-Wulf Fw 190 fighter aircraft, being used as well the larger Junkers Ju 88 and Ju 388L. In the second half of 1944 about 1000 exemplars were built, but their engines were destroyed on the bombing of the Stargard BMW industrial plant. No record has been found about any X-4 reaching combat units.


The X-4 was exhibited in Farnborough, England, in the summer of 1945, presented as a "wire controlled, rocket propelled missile fired from fighter aircraft against heavy bomber formations" which was "electrically controlled through connecting wires to Fw 190".


The basic components of the X-4, as seen on this picture, were (from tip to tail): acoustic probe, seven-screw manhole cover, fuze, warhead, detonators, loose piston actuated by compressed air, compressed-air bottle, spiral fuel deposit taking 28 turns around the compressed-air bottle (on the inner face of the fuselage), hanging hook, wooden wings with roll control ailerons, guidance wire coils, gyroscope, seven-pin connector for connection with launching aircraft, battery, tracing flare (to better keep visual tracking of the missile during guidance) and flight control surfaces (rudders).



Taifun and Tornado

Despite lacking a guidance system, these rockets are interesting because they were the last anti-aircraft system developed by the Nazi Germany, representing a reaction against the futility of the complex and immature missiles fitted with a guidance system. The project Taifun (Typhoon) emerged from an evidently right standpoint from engineer Scheufeln, working at Peenemunde, who pointed that the program Wasserfall did not reach the minimum requirements of cost versus effectiveness. By his own initiative he started to work in the Taifun, a rocket stabilized by rotation which costed only 25 German marks, was fired in salvos and was fitted with the optimal weight of explosive required to destroy a bomber. Specifically, 500 grams to reach an altitude of 15000 meters. The rocket was fitted with a liquid-fuel propulsion plant which provided a high directional precision, accelerating the rocket to a speed of up to 3600 kilometers/hour in only 2.5 seconds. The launcher (again, a conveniently modified mounting of the Flak 18/36 88-millimeter anti-aircraft cannon) fired groups of 30 Taifun at once.

In January 1945, the Taifun F (basic series missile) was already being produced in Peenemunde, but only 600 units had been built at the end of the war. Which remained a mystery was how to arrange the launcher to be aimed with a precision that were at least so good as that achieved by conventional anti-aircraft artillery, regarding very high altitudes. A parallel project was the Tornado, another unguided rocket similar to the Taifun but propelled by solid fuel; its prestations were almost identical to those of the Taifun, but the lack of materials prevented to authorize its production.


The Tornado, an anti-aircraft rocket propelled by solid fuel, could have achieved optimal results if it had been available some years before; when it was perfected, it could not enter production because of the lack of fuel.

Specifications for Taifun F





Article updated: 2018-02-06

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

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Article submitted: 2015-01-23