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V-2 rocket
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The V-2 rocket was the first ballistic missile and first man-made object to achieve sub-orbital spaceflight, the progenitor of all modern rockets. Some 3,225 V-2s were launched as military rockets by the German Wehrmacht against Allied targets in World War II, resulting in the death of an estimated 7,250 military personnel and civilians.
owing successes at Kummersdorf with the first two Aggregate series rockets, Wernher von Braun and Walter Riedel began thinking of a much larger rocket in the summer of 1936 based on a projected 25-metric-ton-thrust engine.
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Encyclopedia
The V-2 rocket was the first ballistic missile and first man-made object to achieve sub-orbital spaceflight, the progenitor of all modern rockets. Some 3,225 V-2s were launched as military rockets by the German Wehrmacht against Allied targets in World War II, resulting in the death of an estimated 7,250 military personnel and civilians.
Developmental history
Following successes at Kummersdorf with the first two Aggregate series rockets, Wernher von Braun and Walter Riedel began thinking of a much larger rocket in the summer of 1936 based on a projected 25-metric-ton-thrust engine. After the A-4 project was postponed after unfavorable aerodynamic stability testing of the A-3 in July 1936, von Braun specified the A-4 performance in 1937, and A-4 design and construction was ordered c1938/1939.
During September 28-30 1939, Der Tag der Weisheit (English: the day of wisdom) conference met at Peenemünde to initiate the funding of university research to solve rocket problems.
By late 1941, the Army Research Center at Peenemünde possessed the technologies essential to the success of the A-4. The three key technologies for the A-4 were large liquid-fuel rocket engines, supersonic aerodynamics, gyroscopic guidance and rudders in jet control. Then Hitler was not particularly impressed by the V-2; he pointed out that it was merely an artillery shell with a longer range and much higher cost.
In early September 1943, von Braun promised the Long-Range Bombardment Commission that the A-4 development was 'practically complete/concluded', but even by the middle of 1944, a complete A-4 parts list was still unavailable.
Hitler probably then was still not impressed with the weapon but was impressed by the enthusiasm of its developers, and needing a "wonder weapon" to maintain German morale, Hitler authorized its deployment in large numbers.
Technical details
At launch the A-4 propelled itself for up to 65 seconds on its own power, and a program motor controlled the pitch to the specified angle at engine shutdown, from which the rocket continued on a free-fall (ballistic) trajectory. The rocket reached a height of 80 km (50 miles) before shutting off the engine.
The fuel and oxidizer pumps were steam turbines, and the steam was produced by concentrated hydrogen peroxide with potassium permanganate catalyst. Both the alcohol and oxygen tanks were an aluminium-magnesium alloy.
The combustion burner reached a temperature of 2500-2700 °C (4500 - 4900 °F). The alcohol-water fuel was pumped along the double wall of the main combustion burner. This cooled the chamber and heated the fuel (regenerative cooling). The fuel was then pumped into the main burner chamber through 1,224 nozzles, which assured the correct mixture of alcohol and oxygen at all times. Small holes also permitted some alcohol to escape directly into the combustion chamber, forming a cooled boundary layer that further protected the wall of the chamber, especially at the throat where the chamber was narrowest. The boundary layer alcohol ignited in contact with the atmosphere, accounting for the long, diffuse exhaust plume. (Later, post-V2 engine designs not employing this alcohol boundary layer cooling show a translucent plume with shock diamonds.)
The V-2 was guided by four external rudders on the tail fins, and four internal graphite vanes at the exit of the motor. The LEV-3 guidance system consisted of two free gyroscopes (a horizon and a vertical) for lateral stabilization, and a gyroscopic accelerometer connected to an electrolytic integrator (engine cut-off occurred when a thin coating of silver was electrochemically eroded off a poorly conducting base).
Some later V-2s used "guide beams" (radio signals transmitted from the ground) to navigate towards the target, but the first models used a simple analog computer that adjusted the azimuth for the rocket, and the flying distance was controlled by the timing of the engine cut-off, "Brennschluss", ground controlled by a Doppler system or by different types of on-board integrating accelerometers. The rocket stopped accelerating and soon reached the top of the (approximately parabolic) flight curve.
The painting of the operational V-2s was mostly a camouflage ragged pattern with several variations, but at the end of the war a plain olive green rocket also appeared. During tests, the rocket was painted in a characteristic black-and-white chessboard pattern, which aided in determining if the rocket was spinning around its longitudinal axis.
Testing
The first successful test flight was the third on October 3 1942:
Two test launches were recovered by the Allies: The Bäckebo Bomb on June 13, 1944 in Sweden and one recovered by Polish resistance on 30 May 1944 from Blizna and transported to the UK during Operation Most III.
Test launches of V-2 rockets (Aggregate-4) were made at Peenemünde, Blizna and Tuchola Forest, and after World War II, at Cuxhaven, White Sands Proving Grounds, Cape Canaveral, and Kapustin Yar.
Reference have been made to Allied photo-reconnaissance in 1945 disclosing a further test site at Rudisleben, near Arnstadt in Thuringia. A concentration camp existed at Jonastal with three very long tunnels toward Arnstadt. The factories associated with Jonastal were codenamed OLGA JASMIN SIEGFRIED and BURG. The overall V-weapon complex, known as S-III lay in Jonastal Valley west of Arnstadt, contained an underground factory for V weapons. G-2 intelligence reports from the US 4th Armoured Division make reference to exploring these underground factories and the v-weapons found inside.
Following the war, the DDR East German Courts held a judicial inquiry into the activities at S-III and the sworn testimony of three people who worked in this underground complex, talk of working on a 30 metre rocket. A further witness above ground recounted that she had seen the night launch of a rocket on 16 March 1945 in the same vicinity.
Various problems were identified during V-2 development and testing:
- To reduce tank pressure and weight, high flow turbopumps were used to boost pressure.
- A short and lighter combustion chamber without burn-through was developed by using centrifugal injection nozzles, a mixing compartment, and a converging nozzle to the throat for homogenous combustion.
- Film cooling was used to prevent burn through at the nozzle throat.
- Relay contacts were made more durable to withstand vibration and prevent thrust cutoff just after lift-off.
- Ensuring that the fuel pipes had tension-free curves reduced the likelihood of explosions at 3000-6000 ft.
- Fins were shaped with clearance to prevent damage as the exhaust jet expanded with altitude.
- To control trajectory at lift off and supersonic speeds, heat-resistant graphite vanes were used as rudders in the exhaust jet.
Airburst problem: Through mid-March 1944, only 4 of the 26 successful Blizna launches had satisfactorily reached the Sarnaki target area due to Luftzerleger (English: in-flight breakup) on entry into the atmosphere. Initially excessive alcohol tank pressure was suspected, and by April 1944 after 5 months of test firings, the cause was still not determined. Major-General Rossmann, the Army Weapons Office department chief, recommended stationing observers in the target area -- cMay/June, Walter Dornberger and Wernher von Braun set up a camp at the center of the Poland target zone (one impact was 300 feet from an armed missile.) After moving to the Heidekraut, SS Mortar Battery 500 of the 836th Artillery Battalion (Motorized) was ordered on August 30 to begin test launches of eighty 'sleeved' rockets. Testing confirmed the so-called 'tin trousers' -- a tube designed to strengthen the forward end of the rocket cladding -- reduced the likelihood of airbursts.
Production
During Autum 1941 the Luftschiffbau Zeppelin GmbH as elected to manufactured the Aggregat 4 rocket propellants tanks and fuselage sections,among the facilities of "Serbs Hall" of Henschel Raxwerke,in Wiener Neustadt as approved for A-4 assembly.in June 1943,British bombing of Operation Bellicose hit the Zeppelin V-2 facility, and production was subsequently moved to the Mittelwerk.some V-2 instalations had been erected in Raxwerke factories during 1943 when on Nov.2 of same year the USAAF striking the factories and stopped all production.
A production line was nearly ready at Peenemünde when the Operation Hydra attack caused the Germans to move production to the Mittelwerk in the Kohnstein where 5,200 V-2 rockets were built.
| Period of Production | Production |
|---|
| Up to 15 Sep 1944 | 1900 | | 15 Sep to 29 Oct 1944 | 900 | | 29 Oct to 24 Nov 1944 | 600 | | 24 Nov to 15 Jan 1945 | 1100 | | 15 Jan to 15 Feb 1945 | 700 | | Total | 5200 |
An estimated 20,000 inmates at Mittelbau-Dora died constructing V-2s; 9000 died from exhaustion and collapse, 350 hanged (including 200 for sabotage), the remainder were shot or died from disease or starvation.
Launch sites
Following Operation Crossbow bombing, initial plans for launching from the massive underground Le Blockhaus and La Coupole or from fixed pads such as near the Chateau du Molay were dropped in favor of mobile launching. Eight main storage dumps were planned and four had been completed by July 1944 (the one at Mery-sur-Oise was begun in August
1943 and completed by February 1944). The missile could be launched practically anywhere, roads running through forests being a particular favorite. The system was so mobile and small that not one Meillerwagen was caught in action by Allied aircraft., although Raymond Baxter reported that he shot at a V2 from his Sptifire as it was launched.
An average of ten V-2s were launched per day and up to 1000 V-2s could be launched per month, given sufficient supply of the rockets.
Operational history
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