Wasserfall

The ("Waterfall remote-controlled anti-aircraft rocket") 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. :²³⁴

Technical characteristics

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 the size. The design also included an additional set of stub wings located at the middle of the fuselage to provide extra manoeuvring capability.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, 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). This hypergolic mixture was forced into the combustion chamber by pressurising the fuel tanks with nitrogen gas released from another tank. was to be launched from rocket bases (code-named ''Vesuvius'') that could tolerate leaked hypergolic fuels in the event of a launch problem.

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.

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.^: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.'' ^: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. ^: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.'' ^:87

The original design had called for a warhead, but because of accuracy concerns it was replaced with a much larger one of , 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

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 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, three 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. Thirty-five trial firings had been completed by the time Peenemünde was evacuated on 17 February 1945.

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

Assessment

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

See also

* Enzian
*
* Henschel Hs 117 ("Butterfly")
* List of missiles
* List of German guided weapons of World War II
* List of surface-to-air missiles
*

References

External links

EMW Wasserfall Luft '46 entry



W-10 Drawing

{{V-weapons

Surface-to-air missiles of Germany
World War II guided missiles of Germany