Aggregat
The Aggregat series (German for "Aggregate") was a set of
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Aggregate_%283D-comparison%29.jpg/220px-Aggregate_%283D-comparison%29.jpg)
A1 (1933)
The A1 was the first rocket design in the Aggregat series. It was designed in 1933 by
A2 (1934)
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Static tests and assembly were completed by 1 October 1934. Two A2s were built for a full-out test, and were named after a
A3 (1935–1937)
Development of the A3 can be traced at least to February 1935 when Major
In March 1936,
The shape of the rocket was based on the 8-mm rifle bullet, in anticipation of supersonic flight. The rocket was 6.7 metres (22 ft) in length, 0.70 metres (2.3 ft) feet in diameter, and weighed 750 kg (1,650 lb) when fueled. Fins were included, for "arrow stability", structurally anchored by an antenna ring. The stabilized platform used a pitch gyro and a yaw gyro, connected to pneumatic servos, which stabilized the platform along the pitch and yaw axes. Electrical carriages on the platform acted as integrating accelerometers. These signals were mixed with those from the SG-33 system, to drive the molybdenum-tungsten jet vane control servomotors. The SG-33 was fixed to the rocket, not the stabilized platform, and used three rate gyros to sense roll, pitch and yaw deviations. Two of the jet vanes rotated in the same direction for pitch and yaw control, and in opposite directions for roll control. The guidance and control system was designed by Fritz Mueller, based on Johannes Maria Boykow's ideas, the technical director of Kreiselgeräte GmbH ("Gyro Instruments Limited").[2]: 53–57
The A3 engine was a scaled-up version of the A2, but with a mushroom-shaped injector at the top of the combustion chamber, based on a design by Walter Riedel. Ethanol was sprayed upwards to mix with the oxygen sprayed downward from jets at the top of the chamber. This increased efficiency and generated higher temperatures.[2]: 56
This was the first of the Aggregat rockets to be
According to another source, one A3 reached a maximum downrange of 12 km (7.5 mi) and maximum altitude of 18 km (11 mi).[citation needed]
With each launch a failure, von Braun and Dornberger looked for the cause. At first there was some thought of an electrostatic charge that prematurely set off the parachute, but this was largely disproved. Ultimately, the failures were attributed to the inadequate design of the rocket's experimental inertial guidance system and minor instabilities in the body and fin design.[13] The control system was found to be unable to keep the rocket from turning with a wind greater than 3.7 metres per second (12 ft/s).[3]: 58 The stable platform gyros were limited to a 30 degree range of motion, and when the platform tumbled, the parachutes deployed. The jet vanes needed to move faster, and have a larger control force, to stop the rolling. The fins were redesigned in the A5, when it was realized an expanding jet plume as the rocket gained altitude, would have destroyed the A3 fin stabilizing antenna ring.[2]: 57
After this unsuccessful series of launches, the A3 was abandoned and A4 work postponed, while work on the A5 commenced.[14][3]: 58
According to Dornberger, the A3 "...had not been equipped to take any payload. It was a purely experimental missile." Similarly, the A5 was to be "for research purposes only."[3]: 50, 66
Specifications
- Length: 6.74 m (22 ft 1 in)
- Diameter: 0.68 m (2 ft 3 in)
- Finspan: 0.93 m (3 ft 1 in)
- Launch mass: 748 kilograms (1650 lb)
- Fuel: Ethanol and liquid oxygen
- Liftoff thrust: 14.7 kN
A5 (1938–1942)
The A5 played a vital role in testing the aerodynamics and technology of the A4. Its rocket motor was identical to the A-3, but with a new control system provided by Siemens, was 5.825 m (19.11 ft) long, with a diameter of 0.78 m (2 ft 7 in) and a takeoff weight of 900 kg (2,000 lb). The A5 was fitted with a Brennschluss receiving set, a parachute recovery system, could stay afloat in water for up to two hours, and was painted yellow and red, aiding recovery. New tail surfaces were tested in the Zeppelin Aircraft Works subsonic tunnel and the supersonic tunnel in Aachen. The internal vanes were now made of graphite instead of molybdenum. Uncontrolled A5s were launched from Griefswalder Oie in late 1938. Models that were 1.5 meters (5 ft) long and 20 centimeters (8 in) in diameter were dropped from Heinkel He 111s starting in September 1938, testing supersonic speeds in the absence of a supersonic wind tunnel. Hellmuth Walter also made models of the A5m which included a hydrogen peroxide motor, with potassium permanganate as a catalyst, and were test launched in March 1939. The final fin configuration was wider, curved outward to accommodate the expanding exhaust gases, included external air vanes, but no ring antenna.[3]: 58–64 [2]: 58–60
The A-5, like the A-3, was fueled with ethanol with liquid oxygen as an
At the conclusion of the A-5 testing, Dornberger stated, "I now knew that we should succeed in creating a weapon with far greater range than any artillery. What we had successfully done with the A-5 must be equally valid, in improved form, for the A-4."[3]: 64
A4/V2 rocket (1942–1945)
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In the late 1920s, Karl Becker realised that a loophole in the Treaty of Versailles allowed Germany to develop rocket weapons. General Becker was very influential during the development of the A4 until he committed suicide on 8 April 1940 following criticism from Adolf Hitler.[16]
The A4 was a full-sized design with a range of about 322 kilometers (200 mi), an initial peak altitude of 89 kilometers (55 mi) and a payload of about a tonne. Versions of the A4 were used in warfare. They included the first ballistic missile and the first projectile to reach outer space.[17]
The propellants of choice continued to be liquid oxygen, with a 75% ethanol and 25% water mixture. The water reduced the flame temperature, acted as a coolant, and reduced thermal stress.[4]
This increase in capability came from a redesign of the A3 engine, now known as the A5, by Walter Thiel. It became clearer that von Braun's designs were turning into useful weapons, and Dornberger moved the team from the artillery testing grounds at Kummersdorf (near Berlin) to Peenemünde, on the island of Usedom on Germany's Baltic coast, to provide more room for testing and greater secrecy. This version was reliable, and by 1941 the team had fired about 70 A5 rockets. The first A4 flew in March 1942, flying about 1.6 kilometers (1 mi) and crashing into the water. The second launch reached an altitude of 11 kilometers (7 mi) before exploding. The third rocket, launched on 3 October 1942, followed its trajectory perfectly. It landed 193 kilometers (120 mi) away, and reached a height of 83 kilometers (52 mi).[18] The highest altitude reached during the war was 174.6 kilometres (108.5 miles) on 20 June 1944.[18]
Production started in 1943 on the rocket. The
Projekt Schwimmweste
In late 1943 German Labour Front (Deutsche Arbeitsfront/DAF) Director, Otto Lafferenz, proposed the idea of a towable watertight container which could hold an A4 rocket. This suggestion progressed to the design of a container of 500 tons displacement to be towed behind a U-boat. Once in firing position, the containers would be trimmed to drop their aft end to a vertical position for launch. The project was dubbed Projekt Schwimmweste (German for "Project Life Jacket") and the containers themselves referred to by the codename Prüfstand XII (German for "Test Rig XII"). Work on the containers was carried out by the Vulkanwerft, and a single example was completed by the end of the war, but never tested with a rocket launch.[22]
A4b/A9
In anticipation of the possibility that launch sites might be forced back into the Reich itself, von Braun and his colleagues were pressured to develop a longer-range version of the A4 known alternatively as A9 and A4b, the reason for the dual designation being that the A4 series had received "national priority"; the A4b designation ensured the availability of scarce resources.[23]
In June 1939, Kurt Patt of the Peenemünde Design Office, proposed wings for converting rocket speed and altitude into aerodynamic lift and range.[24] As the rocket encountered thicker atmosphere on its descent phase, it would execute a pullout and enter a shallow glide, trading speed for distance. Patt also proposed the Flossengeschoss (fin projectile). Both concepts were utilized by Walter Dornberger when he drafted a memo for presentation to Hitler regarding the "America rocket" on 31 July 1940.[25]
Design studies on the A9 began in 1940. In addition to its wings, the A9 would have been somewhat larger than the A4 and its engine would have produced about 30% more thrust. Following wind tunnel testing of models, the design was subsequently modified to replace the wings with fuselage
Development was suspended in 1941, but in 1944 several V2s were modified to an approximation of the A9 configuration under the designation A4b.[26] It was calculated that by fitting wings, the A4's range would be extended to 750 km (470 mi), allowing targets in Britain to be attacked from launch sites within Germany. It was intended that following launch the curve of the A4b's trajectory would become shallower and the rocket would glide toward its target. It was anticipated that interception by enemy aircraft at the end of the glide phase would be almost impossible, as over the target the A-4b was intended to enter a near vertical dive, leaving little time for interception.
The A4b concept was tested by fitting swept back wings to two A4s launched from Blizna. Little development work had been carried out, and the first launch on 27 December 1944 was a complete failure. The second launch attempt, on 24 January 1945, was partially successful, in that the wing broke off, but the A4b still managed to become the first winged guided missile to break the sound barrier and attain Mach 4.[27][28][3]: 219
Variations – Planned, not constructed
A6
A6 was a designation applied to a variant of the A5 test rocket which used different propellants.[15]
Some sources indicate that it was also applied to a speculative proposal for a crewed
A7
The A7 was a winged design that was never fully constructed. It was worked on between 1940 and 1943 at Peenemünde for the Kriegsmarine. The A7 was similar in structure to the A5, but had larger tail unit fins (1.621 m2) in order to obtain greater range in gliding flight. Two unpowered models of the A7 were dropped from aeroplanes in order to test flight stability; no powered test was ever performed. The finished rocket should have produced a takeoff thrust of 15 kN and a takeoff weight of 1000 kg. The design had a diameter of 0.38 m and a length of 5.91 m.[citation needed]
A8
The A8 was a proposed "stretched" variant of the A4, to use storable rocket propellants (most likely nitric acid & kerosene). The design never reached the prototype stage, but further design work was carried out after the war by a German rocket team in France as the "Super V-2". The project was eventually cancelled, but led to the French Véronique and Diamant rocket projects.[15][30]
A9/A10
Aggregat 9/10 | |
---|---|
IRBM second stage[citation needed] | |
Service history | |
In service | test only, not deployed |
Production history | |
Manufacturer | studied by Army Research Center Peenemünde |
Unit cost | none mass-manufactured |
Specifications | |
Mass | 16,259 kg (35,845 pound) |
Length | 14.18 m (46' 6¼") |
Diameter | 1.65 m (5' 5") maximum |
Wingspan | 3.2 m (10' 6") |
Warhead | 1000 kg (2204 pound) payload[31] |
Engine | A9 |
Operational range | 800 km (497.1 miles) (single stage flight) |
Flight altitude | 190 km (118.1 miles) (single stage flight) or 390 km (242.3 miles) (A9/A10 combination) |
Maximum speed | 3,400 m/s (7,600 mph) (A9/A10 two stage combination) |
Launch platform | ground launch pad or A10 |
It was proposed to use an advanced version of the A9 to attack targets on the US mainland from launch sites in Europe, for which it would need to be launched atop a booster stage, the A10.
Design work on the A10 began in 1940, for a projected first flight to take place in 1946. The initial design was carried out by Ludwig Roth und Graupe and was completed on 29 June 1940. Hermann Oberth worked on the design during 1941, and in December 1941 Walter Thiel proposed that the A10 use an engine composed of six bundled A4 engines, which it was thought would give a total thrust of 180 tonnes.
Work on the A10 was resumed in late 1944 under the Projekt Amerika codename, and the A10's design was amended to incorporate a cluster of 6 A4 combustion chambers feeding into a single expansion nozzle. This was later altered to a large single chamber and single nozzle. Test stands were constructed at Peenemunde for firings of the 200 tonne (440,920 lbf) thrust motor.
It was considered that existing guidance systems would not be accurate enough over a distance of 5,000 km, and it was decided to make the A9 piloted. The pilot was to be guided on his terminal glide towards the target by radio beacons on U-boats and by automatic weather stations landed in Greenland and Labrador.
The final design of the A10 booster was approximately 20 m (66 ft) in height. Powered by a 1,670 kN (380,000 lbf) thrust rocket burning diesel oil and nitric acid, during its 50-second burn it would have propelled its A9 second stage to a speed of about 4,300 km/h (2,700 mph).[32] The A9 would then ignite and accelerate an additional 5,760 km/h (3,580 mph), reaching a speed of 10,080 km/h (6,260 mph), a peak altitude of 56 kilometres (35 mi), and covering 4,000 kilometres (2,500 mi) in about 35 minutes. The spent A-10 would descend by brake flaps and parachute to be recovered in the sea and reused.[3]: 130–131
A11
The A11 (Japan Rakete) was a design concept which would have acted as the first stage of a three-stage rocket, the other two stages being the A9 and A10.
The A11 design was shown by von Braun to US officers in Garmisch-Partenkirchen; the drawing was published in 1946 by the US Army. The A11 was shown as using six of the large single-chamber engines proposed for the A10 stage, with a modified A10 second stage nested within the A11. The design also showed the winged A9, indicating a gliding landing or bombing mission. To achieve orbit, either a new "kick stage" would have been required, or the A9 would have to have been lightened. In either case, a payload of approximately 300 kg (660 lb) could have been placed in a low Earth orbit, roughly equivalent to the modern-day
A12
The A12 design if built would have been an orbital rocket. It was proposed as a four-stage vehicle, comprising A12, A11, A10 and A9 stages. Calculations suggested it could place as much as 10 tonnes payload in low Earth orbit, comparable to the later Saturn I rocket of the Apollo program.
The A12 stage itself would have weighed around 3,500 tonnes fully fueled, and would have stood 33 m (108 ft) high. It was to have been propelled by 50 A10 engines, fueled by liquid oxygen and ethanol.[34]
References
Citations
- ^ "Aggregate-1".
- ^ ISBN 9780813031774.
- ^ a b c d e f g h i j Dornberger, Walter (1954). V-2. New York: The Viking Press, Inc. pp. 38–41.
- ^ ISBN 9781563476495.
- ^ "Raketenaggregate „A1" und „A2"", Aggregat 2 (in German), DE, 9 January 2005
{{citation}}
: CS1 maint: location missing publisher (link). - ^ Neufeld, M.J. Von Braun: Dreamer of Space, Engineer of War. New York: Knopf, 2007. p 75.
- ^ Huzel 1962, p. 233.
- ^ Neufeld 1996, p. 81.
- ^ Huzel 1962, p. 236.
- ^ Neufeld 1996, pp. 84–85.
- ^ Huzel 1962, p. 235.
- ^ "Aggregate-3".
- ^ a b Neufeld 1996, pp. 102–5.
- ^ Neufeld 1996, p. 105.
- ^ a b c Michels, Juergen; Przybilski, Olaf (1997). Peenemünde und seine Erben in Ost und West. Bonn: Bernard & Graefe.
- ^ Barber 2017, p. 11.
- ISBN 3-8118-4341-9.
- ^ a b Neufeld 1996.
- McGovern, James(1964). Crossbow and Overcast. New York: W. Morrow. p. 42.
- ISBN 83-211-0521-1.)
{{cite book}}
: CS1 maint: location missing publisher (link - ^ Zak, Anatoly: Russian Space Web: 2009
- ISBN 978-0-7603-3754-7.
- ^ Neufeld 1996, pp. 63, 93, 250, 283.
- ^ Neufeld 1996, p. 92.
- ^ Neufeld 1996, pp. 138, 283.
- ^ Reuter 2000, pp. 90–91.
- ^ Reuter 2000, p. 87.
- ISBN 978-1-85233-722-3.
- ^ "A6". Astronautix. Archived from the original on 7 January 2010.
- ^ Reuter 2000, p. 179.
- ^ Huzel 1962, p. 237.
- ^ Reuter 2000, pp. 91–93.
- ^ Reuter 2000, p. 94.
- ^ Reuter 2000, p. 95.
Bibliography
- Barber, Murray R. (2017), V2 The A4 Rocket From Peenemünde To Redstone, Crecy Publications, ISBN 978-1-90653-753-1
- Huzel, Dieter K. (1981) [1962], Peenemünde to Canaveral (reprint ed.), Greenwood Press, ISBN 0-313-22928-7.
- ISBN 0-674-77650-X.
- Reuter, Claus (2000), The V2 and the German, Russian and American Rocket Program, German Canadian Museum, p. 87, ISBN 978-1-894643-05-4.
Further reading
- "A1", Encyclopedia Astronautica, Astronautix, A2, A3, A5, A7, A8, A-9, A-10 engine, A9/A10/A11, A9/A10/A11/A12
- V2 EMW A4b die bemannte Rakete (in German), DE: Khiechhorn, archived from the original on 14 June 2011, retrieved 2 August 2007.
- "Neubau", Aggregat 2 (in German), DE, 9 January 2005
{{citation}}
: CS1 maint: location missing publisher (link). - "Aggregat 1", Aggregat 2, DE, 9 January 2005
{{citation}}
: CS1 maint: location missing publisher (link). Technical discussion of the A1 (in German), by the same author as the above A2 site. The author has examined primary sources; based on them, he claims that widely repeated data about the A1 is mostly in error. - Original drawings from the development of A4/V2 and others (in German), DE: Digipeer,
20,000
. - The A4 Rocket Part 1 (in German), DE: Bernd Leitenberger.
- The A4 Rocket Part 2 (in German), DE: Bernd Leitenberger.
- "Part Two", V2 (article), Aerospace museum, October 2004, archived from the original on 26 May 2005.
- Space (lecture), University of Oregon, archived from the original on 10 April 2005.
- A8 statistics, Friends-partners, archived from the original on 25 June 2013, retrieved 28 April 2005.
- ISBN 3-7628-0404-4
External links
- "Reconstruction, restoration & refurbishment of a V-2 rocket", Nasa tech (spherical panoramas of the process and milestones)[permanent dead link].