the
Wasserfall missile
Wasserfall
was essentially an anti-aircraft development 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 manoeuvring 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 oxygen used 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% sulphuric acid). This hypergolic
mixture was forced into the combustion chamber by
pressurizing the fuel tanks with nitrogen gas released from
another tank.
Guidance was to be a simple radio control MCLOS system 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 Rhineland was under development. Rhineland used a
transponder in the missile for locating it in flight (as
read by a radio direction finder (RDF) on the ground) and a
radar unit for tracking the target. A simple mechanical
computer guided the missile into the tracking radar beam as
soon as possible after launch, using the transponder and RDF
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.
A second development was underway that used only a single
cross-shaped radar beam that was rotated while pointing at
the target. Like the Rhineland system the missile was first
directed into the beam via the transponder, and from there
would keep itself centred in the beam. It did this by
listening to the radar signal, if it was off course it would
hear pulses instead of a steady signal, and automatically
place itself back in the middle of the beam. However the
high supersonic speed of the Wasserfall 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 terminal guidance system would
have to be added.
The original design called for a 100 kg warhead, but the
accuracy concerns led to the design of a much larger 306 kg
one including a liquid explosive. For daytime use the
operator would detonate the warhead by remote control, while
night-time use was to be by some sort of proximity fuse.
The first models were being tested in March 1943, but a
major setback occurred in August 1943 when Dr. Walter Thiel
was killed in the massive RAF bombing raids on Peenemünde.
The first launch took place on 8 January 1944 and 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
speed of 770 m/s (2,800 km/h) in vertical flight. When the
program was canceled on 6 February 1945 nearly 40 flights
had been made.
characteristics
Primary
Function: surface-to-air missile
Contractor: Flak- Versuchskommando Nord, EMW
Peenemuende
Power Plant: liquid-fuelled rocket motor
Length: 7.85 m
Diameter: 2.51 m
Launch Weight: kg
Speed: 770 m/s
Warhead: 235 kg
Fuses: proximity
Guidance system: MCLOS; operator used input from
radars tracking the missile and target to guide it, using a
radio command link and a joystick
Unit Cost: 7,000–10,000 RM (Reichsmark)
Date Deployed: never
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