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Wasserfall

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Wasserfall
TypeSurface-to-air missile
Place of originNazi Germany
Production history
ManufacturerFlak-Versuchskommando Nord, EMW Peenemünde
Unit cost7,000–10,000 ℛ︁ℳ︁
ProducedMarch 1943
Specifications
Mass3,700 kilograms (8,200 lb)
Length7.85 metres (25.8 ft)
Diameter.864 metres (2 ft 10.0 in)
Warhead235 kilograms (518 lb)
Detonation
mechanism
Proximity

EngineLiquid-propellant rocket motor
Operational
range
25 kilometres (16 mi)
Maximum speed 770 metres per second (1,700 mph)
Guidance
system
Manual command to line of sight (MCLOS); operator used a radio command link to steer the missile along the optical line of sight from launch point to target
Launch
platform
Fixed

The Wasserfall Ferngelenkte FlaRakete ("Waterfall remote-controlled anti-aircraft rocket"[1]: 77 ) was a German guided supersonic surface-to-air missile project of World War II. Development was not completed before the end of the war and it was not used operationally.

The system was based on many of the technologies developed for the V-2 rocket program, including the rocket itself, which was essentially a much scaled-down version of the V-2 airframe. Significant additional development was required, including design and test of an effective guidance system to allow interception of an air target, adoption of hypergolic fuels to allow the missile to stand ready for launch for days or weeks, and the development of a reliable Proximity Fuse. [2]:234

Technical characteristics

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Wasserfall rocket displayed at the National Museum of the United States Air Force, 2007

Wasserfall was essentially an anti-aircraft development of the V-2 rocket, sharing the same general layout and shaping. Since the missile had to fly only to the altitudes of the attacking bombers, and needed a far smaller warhead to destroy these, it could be much smaller than the V-2, about 14 the size. The Wasserfall design also included an additional set of stub wings located at the middle of the fuselage to provide extra manoeuvring capability.[3]: 56–57 Steering during the launch phase was accomplished by four graphite rudders placed in the exhaust stream of the combustion chamber, as in the V-2, but once high airspeeds had been attained this was accomplished by four air rudders mounted on the rocket tail.

Unlike the V-2, Wasserfall was designed to stand ready for periods of up to a month and fire on command, therefore the volatile liquid oxygen used in the V-2 was inappropriate. A new engine design, developed by Dr. Walter Thiel, was based on Visol (vinyl isobutyl ether) and SV-Stoff or red fuming nitric acid (RFNA), (94% nitric acid, 6% dinitrogen tetroxide).[4] This hypergolic mixture was forced into the combustion chamber by pressurising the fuel tanks with nitrogen gas released from another tank. Wasserfall was to be launched from rocket bases (code-named Vesuvius) that could tolerate leaked hypergolic fuels in the event of a launch problem.[1]: 77 

Several guidance systems were in development but none were completed by the end of the war. The simplest (code name Burgund) used a manually operated optical target tracker and a separate manually operated optical missile tracker, each with its own operator. The missile tracker operator was provided with a joystick to send guidance commands to the missile using a modified version of the FuG 203/FuG 230 "Kehl-Straßburg" radio control system.[3]

Because Wasserfall was launched vertically, rather from an angled launcher, it had to be steered to come within the line of sight between the missile tracker operator and the target. This flight path was calculated by an analog electro-mechanical Einlenk Rechner (“Initial Course Computer”). The first six seconds of missile flight were vertical, under the control of the missile internal gyro stabilised autopilot. After this the Einlenk, taking input from the optical target tracker, automatically guided the optical missile tracker (but not the missile) to describe the calculated missile path, as it would be seen by the missile tracker operator. The missile tracker operator had to send guidance commands to the missile to keep it in the moving cross hairs of his optical tracker as it was automatically slewed in azimuth and elevation by the Einlenk, thus causing the Wasserfall to fly the course computed by the Einlenk. Once the missile tracker sight and Wasserfall missile was within 0.5 degrees of the target line of sight, the Einlenk disengaged, allowing the missile tracker operator to maintain the missile on line of the sight with the target until the engagement completed. The missile tracker operator was provided with a control to detonate the missile warhead when the point of closest approach between missile and target was achieved.[3]:82

An optical guidance system for Wasserfall which used the more advanced Fug512/E530 Kogge/Brigg radio control system but was otherwise identical to burgund, was given the code name Franken. [3]:87

Night-time or poor weather use was considerably more complex because neither the target nor the missile would be easily visible. For this role an alternative guidance system, code named Elsass was under development. Elsass used a Wurzburg or Mannheim radar for target tracking and a separate passive missile tracker that picked up a signal from a radio transmitter (known as Ruse) in the missile. As with the optically guided systems, the Einlenk computer directed the missile tracker to provide the missile tracking operator with a course to bring the Wasserfall from vertical launch to line of sight with the target. Once the missile was close to line of sight between the missile tracker and the target, it created a strong blip on the missile tracker operators CRT display. The missle tracker operator then used the joystick to guide the missile so that the blip representing the missile moves to the centre of the missile tracker display. The missile tracker was kept pointing at the target using coordinates fed to it from the target tracking radar. [3]:84

A radar guidance system which used the more advanced Fug512/E530 Kogge/Brigg radio control system but was otherwise identical to Elsass , was given the code name Brabant. [3]:87

The original design had called for a 100 kg (220 lb) warhead, but because of accuracy concerns it was replaced with a much larger one of 306 kilograms (675 lb), based on a liquid explosive. The idea was to create a large blast area effect amidst the enemy bomber stream, which would conceivably bring down several airplanes for each missile deployed. For daytime use the operator would detonate the warhead by remote control.

Development

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Conceptual work began in 1941, and final specifications were defined on 2 November 1942. The first models were being tested in March 1943, but a major setback[citation needed] occurred in August 1943 when Dr. Walter Thiel was killed during the Operation Hydra bombings, the start of the Allied campaign against German V-weapons including V-2 production. After the first successful firing (the third prototype) on 8 March 1944,[3]: 107  three Wasserfall trial launches were completed by the end of June 1944. A launch on 8 January 1945 was a failure, with the engine "fizzling" and launching the missile to only 7 km of altitude at subsonic speeds. The following February saw a successful launch which reached a supersonic speed of 770 m/s (2,800 km/h) in vertical flight.[1]: 69  Thirty-five Wasserfall trial firings had been completed by the time Peenemünde was evacuated on 17 February 1945.[3]: 107 

The Bäckebo rocket, a V-2 rocket using Wasserfall radio guidance, crashed in Sweden on 13 June 1944.

Assessment

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According to Albert Speer and Carl Krauch it could have devastated the Allied bomber fleets.[5] Speer, Germany's Reich Minister of Armaments and War Production, later claimed:[6]

To this day, I am convinced that substantial deployment of Wasserfall from the spring of 1944 onward, together with an uncompromising use of the jet fighters as air defense interceptors, would have essentially stalled the Allied strategic bombing offensive against our industry. We would have well been able to do that – after all, we managed to manufacture 900 V-2 rockets per month at a later time when resources were already much more limited.

— Albert Speer, Reich Minister of Armaments and War Production, memoir.

See also

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References

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  1. ^ a b c Klee, Ernst; Merk, Otto (1965) [1963]. The Birth of the Missile: The Secrets of Peenemünde. Hamburg: Gerhard Stalling Verlag. pp. 69, 70, 77.
  2. ^ Neufeld, Michael J. (1995). The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era. New York: Free Press. p. 235. ISBN 0-02-922895-6.
  3. ^ a b c d e f g h Pocock, Rowland F. (1967). German Guided Missiles of the Second World War. New York: Arco Publishing Company, Inc. pp. 71, 81, 87, 107.
  4. ^ Brügge, Norbert. "The history of post-war rockets on base German WW-II "Wasserfall" missile propulsion". b14643.de. Retrieved 19 April 2020.
  5. ^ Speer, Albert (1997) [1970]. Inside the Third Reich. Translated by Winston, Richard and Clara. Simon & Schuster. p. 492. ISBN 0-684-82949-5.
  6. ^ Speer, Albert (1969). Erinnerungen (in German). Propyläen Verlag. p. 375. ISBN 3-550-06074-2.
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