The V-2 (A4) Ballistic Missile Technology
German team of specialists that came to the United States after the war
was initially assigned to Fort Bliss, Texas,
where they reassembled and tested V-2 rockets brought to the United States
Later they went to Redstone Arsenal in Huntsville, Alabama.
The V-2 was the first ballistic missile
used in warfare and a significant advancement in rocket technology. Also
known as the A4, it was developed by Nazi Germany during World War II and
used against the Allies, primarily as a terror weapon. Because it was so
inaccurate (it could barely hit a city-size target), it could not be used
against specific military targets and was instead used against civilians
who had no defence against it as it came screaming down from the upper
atmosphere. Adolf Hitler named it his "Vengeance Weapon 2"or "V-2" because
it wreaked vengeance upon a helpless population. (The "Vengeance Weapon
1," or "V-1", was a cruise missile.)
Despite its relative inaccuracy, the V-2
incorporated several major technological advances in rocketry. Its engine
was 17 times more powerful than the largest rocket motor constructed up to
that time; it flew at five times the speed of sound; and it could still
fly relatively accurately to targets nearly 190 miles (306 kilometres)
Work began on the A4 in 1940 but
proceeded slowly at first. The rocket team employed some of the best
aerodynamicists in Germany, who conducted systematic tests on subscale
models. In August 1941, Hitler ordered the completion of development of
the A4 and the production of several hundred test and pre-production
vehicles. Testing occurred during 1941, when tests of the large engine
required for the rocket kept ending in explosions.
(A-4) on a test stand at Peenemunde, Germany, during the war.
It carried a 2,000pound warhead at speeds of about 3,600 mph and had a
range of about 220 miles.
The high, arching flight of the V2 carried it to an attitude of about 100
The A4 incorporated four major advances:
its powerful engine, its aerodynamic shape, its innovative guidance
system, and its radio transmission system. Together, these produced a
terrifying weapon that ultimately had little military value to the
The rocket engine was fuelled by an
alcohol and water combination, with liquid oxygen serving as an oxidizer
that enabled the fuel to burn, just as oxygen enables wood to burn. The
fuel and oxidizer were pumped into a main combustion chamber where they
mixed and then ignited, producing 56,000 pounds (249,100 newtons) of
thrust, which escaped out of the rocket nozzle at the tail of the vehicle.
The engine contained a number of key
technological innovations that enabled it to achieve significantly higher
thrust. First, it had a new type of fuel nozzle for injecting the watered
alcohol into the engine. These nozzles sprayed the fuel out in a
rotational pattern that caused it to atomize better (in other words,
create very small fuel droplets that had more surface area, like the water
coming out of a spray bottle) so that it mixed better with the oxidizer
and therefore burned more efficiently.
A second innovation was the use of a
pre-chamber system that mixed the propellant and oxidizer in small
chambers above the main combustion chamber. This produced better mixing
before burning and kept the flames farther from the nozzles, preventing
heat damage to the nozzles.
A third innovation was the use of a
shorter, rounder combustion chamber, which mixed the propellants better
than an earlier design with a longer chamber. The final innovation was the
rocket exhaust nozzle. Previous nozzles had a 10-12-degree angle of
opening between the sides of the cone, resulting in a long, thin cone. But
the A4 engine had a nozzle with an angle of 30 degrees. This reduced
friction between the exhaust gases and the wall and also resulted in a
Because the rocket would travel so
fast—faster than any other object at that time—its aerodynamic shape was
very important, particularly the fins for controlling the rocket. But
determining the proper shape was difficult because no wind tunnel existed
at the time that could test objects at such high speeds. The Germans built
a world-class aerodynamic institute at their rocket test centre at
Peenemünde, with several supersonic wind tunnels. These tunnels were not
ready in time, however, and many of the key decisions concerning the A4's
shape were made from educated guesses and confirmed later. For instance,
the unusual rounded shape of the A4 (when compared with modern rockets)
was due to the fact that it was based on the shape of a rifle bullet.
Designers figured that since a rifle bullet flew through the air without
tumbling, a rocket using the same shape would do the same.
engine used in a German V-2 missile during World War II.
The third primary technological advance
of the A4 was in the area of guidance. Early rockets had no guidance
system at all and could be aimed only in a general direction. Later, some
simple guidance systems were adopted that directed rockets to pitch over
in flight to aim toward a target. But the A4 had to fly a long distance
with some degree of accuracy to hit its target, so it required a system
for pointing it in the right direction and shutting off the engine once
the proper velocity was achieved. This was achieved through the use of
what is called an inertial guidance system, a system in which a stabilized
platform remains fixed in space regardless of how the vehicle moves around
it. This stabilized platform allows for measuring the position or
acceleration of the vehicle, since the platform remains pointed in one
direction and the changes in the vehicle can be measured compared to the
stable platform. In the middle of the rocket exhaust were four vanes that
were used to deflect the thrust and steer the rocket based upon commands
from the guidance unit. The A4 system was significantly more advanced than
previous guidance systems. Still, despite this advanced system, the A4
could hit only a city-sized target from 190 miles (306 kilometres) away.
A fourth advance was the development of
a radio transmission system that could relay information about the
missile's performance to the ground. Earlier test missiles used a movie
camera to record an oscilloscope, which was a device that projected a wave
on a screen indicating the rocket's performance. The film was then
retrieved when the rocket splashed down. But because the A4 test flights
would cover hundreds of miles and recovery was nearly impossible, the
engineers needed a means of "tele-metering" information to a ground
station. This development, now referred to as telemetry, became common to
all rocket test programs, as well as to many aircraft test programs.
The A4 was 46 feet (14 meters) long and
five feet (1.5 meters) in diameter at its thickest spot. Its fins spanned
nearly 12 feet (3.7 meters) at the base of the rocket, and it weighed
45,000 pounds (20,412 kilograms). It had a 2,000-pound (907-kilogram)
warhead that stayed attached to the rocket throughout flight, and the
entire missile crashed down on its target. Its first successful flight was
on October 3, 1942.
Thousands of A4/V-2 rockets were fired
during the war. After the war ended, many members of the rocket team that
developed the A4, including Wernher von Braun, went to the United States
or the Soviet Union and assisted in the development of these countries'
ballistic missile programs.