Surface to air missile
manufacturer=Flak- Versuchskommando Nord, EMW Peenemuende
engine=liquid-fueled rocket motor
MCLOS(Manual Command to Line Of Sight); operator used a radio command link to steer the missile along the optical line of sight from launch point to target.
The "Wasserfall Ferngelenkte Flakrakete" ( _en. Waterfall Remote-Controlled A-A Rocket, also known as "Aggregat 5") [Ernst Klee & Otto Merk. "The Birth of the Missile: The Secrets of Peenemünde" Gerhard Stalling Verlag:Hamburg 1963 (English translation 1965) p 77] was a
World War IIguided surface-to-air missiledeveloped at Peenemünde, Germany. One of the German Wunderwaffen, the Wasserfall design was used as a basis for both the American Hermes-A1 missile and a Sovietresearch programme under the codename R-101 after World War II.
Wasserfall was essentially an
anti-aircraftdevelopment of the V2 rocket, sharing the same general layout and shaping. Since the missile had to fly only to the altitudes of the attacking bombers, it could be much smaller than the V2, about 1/4 the size. The Wasserfall design also included an additional set of fins located at the middle of the fuselage to provide extra maneuvering capability.
Unlike the V2, Wasserfall was designed to stand ready for periods of up to a month and fire on command, therefore the volatile
liquid oxygenused in the V2 was inappropriate. A new engine design, developed by Dr. Walter Thiel, was based on "Visol" (vinyl isobutyl ether) and " SV-Stoff", or "Salbei", (90% nitric acid, 10% sulfuric acid). This hypergolicmixture was forced into the combustion chamber by pressurizing the fuel tanks with nitrogengas 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. [Klee and Merk. 70]
Guidance was to be a simple
radio control MCLOSsystem for use against daytime targets, but night-time use was considerably more complex because neither the target nor the missile would be easily visible. For this role a new system known as "Rheinland" was under development. Rheinland used a radarunit for tracking the target and a transponderin the missile for locating it in flight, read by a radio direction finderon the ground). A simple analog computerguided the missile into the tracking radar beam as soon as possible after launch, using the transponder to locate it, at which point the operator could see both "blips" on a single display, and guide the missile onto the target as during the day. Steering during the launch phase was accomplished by four graphite rudders placed in the muzzle of the combustion chamber, and (once high airspeeds had been attained) by the four air rudders mounted on the rocket tail. Commands were sent to the missile using a modified version of the "Kehl-Strassburg" (code name Burgund) [Pocock. 71 81 87 107] joy-stick system used to direct Henschel Hs 293glide bomb, which had some significant successes against Allied ships in the Mediterranean. [Neufeld, Michael J. "The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era." The Free Press: New York, 1995. (p 235)]
A second development was underway that used only a single cross-shaped radar beam that was rotated while pointing at the target. Like the Rheinland system the missile was first directed into the beam via the transponder, and from there would keep itself centered in the beam by means of a
negative feedbacksystem that listened to the radar signal; if it were off course it would hear pulses instead of a steady signal, and automatically place itself back in the middle of the beam. However the supersonicspeed of the Wasserfall (up to Mach 2) meant that the accuracy of the system would have to be very high in order to get the missile close to its target, and it was generally accepted that some sort of infrared-homingterminal guidance system would have to be added.
The original design had called for a 100 kg warhead, but because of accuracy concerns it was replaced with a much larger one (306 kg) 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, while night-time use was to be by some sort of
Conceptual work began in 1941, and final specifications were defined on November 2, 1942. The first models were being tested in March 1943, but a major setback occurred in August 1943 when Dr.
Walter Thielwas killed in the massive RAF bombing raids on Peenemünde. After the first successful firing (the third prototype) on March 8, 1944, [Pocock, Rowland F. "German Guided Missiles of the Second World War" Arco Publishing Company, Inc.:New York. 1967 (p 107)] Three Wasserfall trial launches were completed by the end of June 1944. A launch on 8 January 1944was a failure, with the engine "fizzling" and launching the missile to only 7 km of altitude at subsonicspeeds. The following February saw a successful launch which reached a speed of 770 m/s (2,800 km/h) in vertical flight. [Klee and Merk. 69] Thirty-five Wasserfall trial firings had been completed by the time Peenemünde was evacuated on February 17, 1945. [Pocock. 107 -- A claim in Christian Zentner's 1977 book, Lexikon des Zweiten Weltkriegs (ISBN 3-517-00639-4) that up to 50 missiles were fired against Allied bombers is inaccurate.]
A V-2 rocket using Wasserfall radio guidance crashed in Sweden on June 13, 1944.
It is one of the mysteries of the Third Reich why Hitler chose not to deploy the Wasserfall in large numbers. According to
Speerand others, it could have devastated the Allied bomber fleets. Some have said the Wasserfall did not appeal to Hitler because it was a defensive, not offensive weapon, but at the same time other, much less effective weapons, such as the Me 163, were being pursued.
The project enjoyed little support in its earlier stages. From 1943 onwards, when the Allied strategic bombing offensive had already started, most of the resources "Wasserfall" would have needed to become operational went to the offensive-minded
V2 rocketproject instead. [Frederick Ordway et al, "The Rocket Team", 1979]
In his memoirs
Albert Speer, Nazi Germany's Minister for Armaments and War Production during the second half of the war, later expressed his conviction that putting "Wasserfall" on the backburner might have been an error:
"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 V2 rockets per month at a later time when resources were already much more limited." [Albert Speer, "Erinnerungen". Propyläen Verlag 1969, (ISBN 3-550-06074-2) p 375]
* [http://www.luft46.com/missile/wasserfl.html Wasserfall technical article, construction plans and test flight photos]
* [http://www.cloudster.com/RealHardware/Wasserfal/WasserfalTop.htm Collection of Wasserfall photos]
* [http://www.ausairpower.net/DT-MS-1006.pdf Genesis of the Surface to Air Missile (Defence Today)]
* [http://www.ausairpower.net/Wasserfall-W-10-2T.gifWasserfall W-10 Drawing]
List of missiles
List of World War II guided missiles of Germany
List of surface-to-air missiles
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