Submarines and their Weapons - Aircraft of World War II

SURFACE-TO-SURFACE MISSILES
but with the same motor. The main difference
between these and the earlier design was to be in the
profile of its flight path, because now the requirement
was not simply to send a rocket straight up into the
atmosphere, but to launch it at a terrestrial target hundreds
of kilometres away, and for that, a sophisticated
guidance package was required. In the case of a small
device like the V1, basic direction was simply a matter
of aligning the launch ramp with the azimuth of
the target, and then relying on a gyrocompass to apply
small corrections. But steering the ballistic missile to
its target would be quite another matter, since it would
have to be launched vertically, and then tipped over in
the precise direction of the target to an angle of 41
degrees from the horizontal and maintained there.
Range was determined by the length of the burn, and
that meant that propellant cut-off had to be precise
and instantaneous. Cut-off was actuated initially by a
radio signal from the ground, and was the only external
factor applied after the launch sequence had been
initiated (and this, too, being later automated). With-
Below: The RAF launched a major raid on Peenmünde on
the night of 17/18 August 1943, and caused considerable
damage, particularly to accommodation blocks. Both
slave labourers and research staff died in the raid.
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out going too far into the intricacies of the matter, to
achieve a proper degree of directional stability in a
ballistic missile it is necessary to be able to control its
movement in three axes: pitch (to achieve and maintain
the proper angle of climb); yaw (side-to-side
movement, to correct the heading); and spin, which is
a natural tendency of a cylindrical body in motion, but
which makes controlling pitch and yaw by means of
rudders almost impossible, and which must be
damped out. To make matters worse, the characteristics
of the missile - in particular the all-important
centre of gravity - change as its fuel is consumed, and
its flight characteristics change no less drastically as it
climbs into and through the upper atmosphere and
then descends again on its parabolic course.
EPOCH-MAKING RESEARCH
All in all, the problems of guidance were the most
complex Wernher von Braun's team had to face, and
they solved them definitively and, we may add, with
nothing more sophisticated than slide-rules and
mechanical calculators; it is perhaps significant that
some of the first simple computers were produced to
solve ballistic problems. The team used three-axis
gyroscopes controlling small rudders built into the
tips of the fins, supplemented by deflector vanes,