G7 (torpedo)
| G7 (torpedo) | |
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| General Information | |
| Designation: | Torpedo G 7a |
| Country of origin: | Germany |
| Working time: | 1934 to 1960s |
| Technical specifications | |
| Length: | 7.163 meters |
| Diameter: | 533 millimeters |
| Combat weight: | 1538 kilograms (version G 7a) |
| Drive: | - Petroleum-powered steam gas engine (G 7a) ( Brotherhood machine ) |
| Speed: | 44 knots |
| Range: | 6 kilometers (12 km at 30 kn) |
| Furnishing | |
| Warhead: | 280 kilograms of gunwool 36 |
| Target location: | no |
| Steering: | Gyroscopic orbit stabilization |
| Ignition devices: |
Impact, magneto |
| Weapon platforms: |
Submarines and smaller surface units |
| Export customers: | |
| Lists on the subject | |
The G 7 was the most important torpedo type of the German Imperial Navy , Reichsmarine and later the Kriegsmarine in the Second World War . With a caliber of 21 inches (corresponds to 533 mm → letter "G") it was a little over 7 meters long and was mainly built in the two versions G 7a with steam gas engine ( Brotherhood machine ) and G 7e with electric drive ( DC motor ). On this basis, various variants such as area search torpedo (FAT) and position-independent torpedo (LUT) were later developed. The torpedo G 7es (electric / sonar ) or T V "Zaunkönig" with acoustic self-steering was a G-7 modification. On the basis of the G 7, smaller (shorter) torpedo types were developed on a trial basis under the designation G 5 .
The G 7e was used on submarines and the G 7a on surface units and as a reserve torpedo on submarines. At the beginning of the Second World War, when used by submarines, due to insufficient testing of series torpedoes, frequent torpedoes fail, especially in combination with magnetos . This was known as the torpedo crisis and it meant that the modern magneto ignition could temporarily no longer be used. The G 7 was based on developments from before the First World War . Series production took place from 1934 until the end of the war, but remnants of the German G-7 torpedoes were still in use after the war until the 1960s, in addition to the German Navy also by Norway and Denmark.
development
In Germany, torpedoes were initially developed by the Schwartzkopff company, while the Imperial Navy initially obtained its torpedoes from the Whitehead company in Fiume. However, at the end of the 1870s, the so-called “torpedo workshop” (today: Wehrtechnische Dienststelle 71 ) was set up by the navy in Eckernförde for the independent development and shooting of the torpedoes. In the course of the 1880s, this increasingly developed into the center of research and production of German torpedo weapons. The remaining part of the torpedo workshop was continued as the Eckernförde torpedo testing facility (TVA) after the First World War . In 1942, the Neubrandenburg torpedo testing facility on Lake Tollensesee was added. Both TVA were blown up in 1945. The “Hexengrund” test facility near Gdynia (then “Gotenhafen”) carried out tests from 1942 to 1945, primarily for the air force .
precursor
The road to the G 7 torpedo began in 1906 with an order from the Reichsmarinamt to the torpedo workshop in Eckernförde to develop a universal torpedo for larger surface units. The combat distance for surface ships had grown so much at this time that the performance of the model C / 06 severely restricted its application possibilities. With a diameter of 45 cm and a length of 6 m, the range of up to 5000 m could no longer be meaningfully increased with the technology of the time.
The 50 cm caliber was chosen for the new torpedoes and two types of torpedoes with a length of 6 and 7 m were developed as G / 6 and G / 7. The seven-meter-long G / 7 was powered purely by steam. A much denser and stronger mixture of Hexa and TNT was used as a new explosive in comparison to the previously used wet gunwool .
The straight-line problem, which had kept the effective range of the C torpedoes well below the range of the engine, was solved by the development of a two-rotor system. Two gyroscopes alternately took over the stabilization, while the other was re-accelerated with compressed air. The spread was reduced from 2% to 1% despite the longer running distance.
From 1914 all German capital ships were equipped with the G / 7 torpedo. From 1917 the G / 7 and a variant were also used on large submarines. In 1914 alone, 765 G / 7 torpedoes were commissioned, 203 pieces were fired during the war, plus 90 of the G / 7AV variant.
Because gas or steam gas powered torpedoes left a telltale trail of exhaust gas bubbles, the development of a non-marking electric powered torpedo was planned for use on submarines. However, this was not developed by the torpedo workshop, but by Siemens & Halske . The Julius Pintsch AG (Berlin and Fürstenwalde ) should take over the housing production and assembly. By the end of 1916, binding construction documents had been drawn up and the construction of three prototypes commissioned. To simplify the development, the control and ignition devices of the compressed air torpedoes were retained and a compressed air cylinder was provided for their operation. Since the necessary number of accumulator elements could not be installed for weight reasons , the speed initially remained at 24-26 knots. To achieve the projected 30 knots at a distance of 1500 m, the torpedo was extended to 7 m. This version was given the designation E / 7 for the first time. Nevertheless, the development of a new motor and propeller with a higher pitch (for lower speed) became necessary. The development dragged on until July 1918. Of the order for 1200 E / 7 torpedoes, the first should be completed in early 1919, so that the electric motorpedo was no longer used in the First World War.
After the First World War, Germany was banned from producing torpedoes. With part of the facilities of the former torpedo workshop, the Torpedoversuchsanstalt (TVA) was founded in 1919 by the Provisional Reichsmarine , which officially had the task of maintaining the torpedoes that were still in existence. In 1923, TVA also received a development department that was initially supposed to modernize the technology in the existing models, which was now almost ten years old. B. should continue the development of a magneto that was not completed during the World War . Because of the ban on submarines, the Reichsmarine initially only worked on torpedoes for surface units. The G / 7 torpedoes were profoundly redesigned in the process. By 1926, the G / 7 was able to increase its speed to 40 knots thanks to a more aerodynamic external shape, an increase in the working pressure of the engine and new propellers . To this end, extensive changes were made to the engines and a seawater cooling system with a separate pump was installed. These torpedoes now bore the designation G 7s (to be distinguished from the later project of an acoustic self-torpedo).
By converting the motors from slide control to valve control , the next step was to increase the cost-effectiveness and thus the running distance of the torpedoes. Improved materials made it possible to increase the boiler pressure to 200 bar. These torpedo variants were now called G 7v and G 7v *.
The development of the electrically driven submarine torpedo E / 7 continued at this time at Siemens & Halske in cooperation with the Accumulatoren Fabrik AG ( AFA ). Delays arose in the provision of suitable electric motors by Siemens-Schuckertwerke and more powerful AFA accumulators. In order to circumvent the restrictions in torpedo construction, efforts were made there to find foreign partners. Negotiations with Sweden began in the mid-1920s, which resulted in the construction and testing of three e-torpedoes under the designation M / 29 A: 1 in 1929. However, there were no follow-up orders. The attempts to collaborate with Spain failed in 1931 (see below).
Development to the G 7
The move to the G 7 was made in 1929 through cooperation with the Spanish Navy. The 21- inch (533 mm) was chosen there. Both the steam gas-powered and the electric torpedo were intended to be produced in Spain on the basis of the plans drawn up by the Germans. Negotiations turned out to be difficult as the Spanish entrepreneur Echevarrieta did not have sufficient financial resources for this project and ended in 1931 with the bankruptcy of the Spanish company.
G 7a
The steam gas-powered torpedoes were then built in Germany. The larger diameter now allowed an increase in performance in almost all areas. The warhead could be enlarged, and the increased boiler capacity allowed a greater range at higher speed. The engine of the G 7v was basically retained, but the larger piston stroke now possible increased its output by almost 50%. A new detonator and straight running apparatus (VIII) were installed. The previously used Woolwich guide fins had to be exchanged for a whitehead tail, as there were significant ballistic problems in certain shooting positions. The Whitehead tail had a higher flow resistance, so that the maximum speed dropped by one knot to 44 knots.
The components and materials have been revised to allow for efficient series production when adapting to the larger shell. For example, shapes that are unfavorable in terms of casting technology were avoided, pressed parts were preferred and materials and parts according to DIN were used wherever possible . In March 1933, development of the G 7a was officially declared complete.
In the summer of 1934 the first shooting was carried out as part of the fleet test. At that time, however, there were no series torpedoes available to the industry, but test torpedoes from the torpedo research institute were used. The good results of this troop test belied the problems of series production, the elimination of which took until 1942. Above all, the depth control proved to be inadequate and contributed to the so-called torpedo crisis .
G 7e
The experience of the two attempts at international cooperation flowed into the planning of a German electric motor pedo production, which began in 1932 at the Torpedo Research Institute. For the torpedo with the designation G 7e, the dimensions, control unit and warhead of the already advanced G 7a should be used. It should now reach 30 kn at 3000 m. The first prototypes then had an even higher performance in 1934 through the use of improved batteries. However, due to the lack of other torpedoes in an export submarine, these went to Turkey.
Production of the G 7e for the German Navy began in 1936. In contrast to the G 7a, however, these torpedoes continued to have Woolwich tail fins, which did not cause any problems when fired underwater. The torpedo now reached 30 kn at 5000 m. When the first series torpedoes were being tested at the end of 1936, it was noticed that the torpedoes were running too deep. This was compensated for by a modified depth spring. The real cause was not recognized, however, and this paved the way for the problems of 1940 .
designation
The name of the torpedo corresponded to the current nomenclature system of the Kriegsmarine for torpedoes:
- G for caliber 533 mm
- 7 for the length of (rounded) 7 m
- Attached lower case letter for the type of drive:
- a for compressed air drive or steam gas drive
- e for electric drive with lead-acid batteries
- d for electric drive with magnesium-carbon batteries
- u for Walter drive with high pressure oxygen
- p for Walter drive with steam under high pressure
- r for Walter jet propulsion
- additional lower case letter:
- s for acoustic self-steering ( sonar )
- t for Walter drive as a turbine
- k for Walter drive as a piston engine
- w and i for Italian- type torpedoes
Designs
G 7a (TI)
The G 7a was powered by steam-gas propulsion, which used petroleum as fuel, and ran at three selectable speeds of either 30, 40 or later 44 knots . The 1538 kg torpedo could cover a distance of 12, 7.5 or 6 km. However, since the drive emitted a clearly visible trace of vapor bubbles, this torpedo was not used as the basis for guided torpedoes, but only for the FAT and LUT programs. The torpedo's warhead contained 280 kg of gunwool 36 .
With the introduction of the type G 7e on the German submarines, the G 7a torpedoes were mostly only carried as reserve armament for night attacks and were partially banned from newer boats. It remained the standard torpedo of surface ships. Remnants were still used after the war (e.g. by the Norwegian Navy).
A version of the G 7a is the T XIV, which was significantly lighter at 1352 kg. It was specially developed for use on small submarines and was designed for use on short distances (34 kn / 3.4 km). The G 7as version, code name “Möwe”, uses the same acoustic seeker head as the T XI “Zaunkönig II”.
G 7e (T II / T III)
The G 7e was electrically driven by an eight-pole direct current motor ("main current" or series motor / current designation) of the type GL 231/75 . This special development by Siemens-Schuckertwerke (SSW) weighed 107 kg and delivered 65 kW / 88 hp for a 30 knot shot speed at a speed of 1700 min −1 and an average current of 930 amperes. Further data were:
- 72 kW / 98 hp at 1755 min -1 (91 volts at 950 A)
- 60 kW / 82 hp at 1590 min -1 (83 volts at 885 A)
The G 7e with electric drive, which was ready for use in the early 1930s, had a lower speed and distance, but did not leave any visible blister marks like the G 7a. The G 7e warhead was just as powerful as that of its predecessor. The first G 7e (Type T II) ran up to 5 km; the version T IIIa with improved battery up to 7.5 km.
The accumulator used in the T II - battery from Accumulatoren Fabrik AG (AFA - renamed VARTA in 1962 ) of type 13 T 210 weighed 665 kg and consisted of 52 lead-acid cells with 13 positive plates each 210 mm high, which were placed one behind the other in two troughs of 26 cells each were housed. With battery heating, a distance of 5000 meters was possible at 30 knots shooting speed; without heating it was only 3000 meters.
The T II version was quickly replaced by the T III version with the 17 T 210 battery (52 cells each with 17 positive plates of 210 mm height in two troughs of 1.42 m length, capacity 130 Ah, weight 800 kg). The version T IIIa had two additional cells (together 54 pieces, weight 830 kg, 135 Ah), which enabled 7500 meters of running distance. FAT and LUT versions of the T-III / IIIa torpedoes were also made.
The G 7e remained the starting point for further torpedoes:
- T IIIb: lighter version that eventually powered the submarine micro types negro and martens use found
- T IIIc: lighter version with a speed of 18.5 kn and a range of 4 km, especially for small submarines
- T IIId " Dachshund ": long-range version extended to 11 m with a speed of 9 kn and a range of 57 km, LUT capabilities
- T IIIe "Kreuzotter": 20 kn fast and 7.5 km long light version
- T VI: T II upgrade with 300 kg warhead and LUT capabilities
- TX “Spider”: T II-based experimental torpedo with remote control via wire
G 7es (TV)
The first operational torpedo type of the Kriegsmarine with acoustic guidance had the code name “ Wren ” or “Device 45” and was specially designed as a weapon against destroyers and anti- submarine ships such as corvettes . The seeker head automatically steered it in the direction of the sound of a ship's propeller. Because of the short blocked section of 400 meters, in which the torpedo was not yet armed, you had to go down immediately after a shot from the bow tubes in order not to endanger your own submarine.
The torpedo, which was also electrically powered, weighed 1511 kg (+/- 25 kg) and had a running distance of 5700 meters (unheated 5000 m) at a speed of 24.5 kn. The new battery of type 13 T 210 special weighed 446 kg, had a capacity of 93 Ah and consisted of 36 cells each with 13 positive plates of 210 mm height in just one trough. The engine had an output of 40 kW / 55 PS at 1350 min −1. Later modifications (T Va and Vb) sacrificed speed (21.5 kn) in favor of range (8 km). The T Va was specially designed for the use of speed boats.
The following experimental torpedoes have been developed:
- T IV “Falcon”: was the forerunner of the “Wren” and was significantly slower at 20 knots
- T XI "Zaunkönig II": Performance data correspond to those of the TV, but with a modified straight-ahead and depth device as well as adjustable blocking distance. The differently designed and therefore quieter drive screw generated less interference and, together with the new seeker head, increased the probability of hits considerably. The T XI was designed for the new Type XXI boats that had no stern tubes.
- "Geier": This torpedo was operated with an active sonar and should find its targets by echo tracking
- "Lerche": This torpedo was guided remotely via a wire connection
G 7 good
The ut version of the G 7 only retained its project character during wartime and was primarily conspicuous because of the Walter drive used .
Versions of this type were:
- T VII “Steinbarsch”: 45 knots fast, 8 km far-reaching and LUT program
- T VIII "Turbot": performance comparable to T VII
- T XIII "K-Butt": much easier should, on small submarines like the orca are used
- “Schildbutt”: Walter test model with seawater injection
- “Stone whale”: experimental model with a circular drive
Other developments
A few other experimental torpedoes were manufactured or designed on the basis of the G-7. These were:
- G 7m: Development with closed-circuit drive , 40 kn speed and 12 km range
- G 7d: Development with a Walter turbine using the cold process
- G 7p: propelled by an electric motor with magnesium-carbon batteries, 40 kn speed
- G 7uk "Klippfisch": Driven by Walter piston engine, 40 kn and 6.5 km range
literature
- Eberhard Rössler : The torpedoes of the German submarines . Koehler, Herford 1984, ISBN 3-7822-0328-3 .
Web links
Individual evidence
- ↑ Eberhard Rössler: The torpedoes of the German submarines . Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 . P. 36 f.
- ↑ Eberhard Rössler: The torpedoes of the German submarines . Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 . Pp. 42, 50
- ↑ Eberhard Rössler: The torpedoes of the German submarines . Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 . P. 45 ff.
- ↑ Eberhard Rössler: '' The torpedoes of the German submarines ''. Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 , p. 51 ff.
- ↑ Eberhard Rössler: '' The torpedoes of the German submarines ''. Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 , pp. 65 f.
- ↑ Eberhard Rössler: The torpedoes of the German submarines . Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 , p. 55 ff.
- ↑ Eberhard Rössler: The torpedoes of the German submarines . Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 . Pp. 58, 60 f.
- ↑ Eberhard Rössler: The torpedoes of the German submarines . Mittler Verlag Hamburg, Berlin, Bonn 2005. ISBN 3-8132-0842-7 . P. 64 ff.
- ↑ Rössler 1984, pp. 74-76
- ↑ 500 kg according to Harald Fock: Z-vor! International development and war missions of destroyers and torpedo boats, vol. 1. 1914 to 1939. Koehlers Verlagsgesellschaft mbH, Hamburg 2001, ISBN 3-7822-0762-9 , p. 41.
- ↑ Rössler 1984, p. 74
- ↑ Rössler 1984, p. 145
- ↑ Rössler 1984, p. 143