Activation of new aaa units - Air Defense Artillery

An Antiaircraft Defense Of Washington
By Colonel Earl Wentworth Thomson, C~-RES.
"Should he not be taught,
E'en by the price that others set upon it,
The value of that jewel he had to guard?"
TENNYSON.
Early in 1944 as the pace of the strategic bombing of the
Allies became faster and faster-by night the tremendous
tonnage of the Royal Air Force on important cities by area
bombing, and by day the precision bombing of the Eighth
and Fifteenth Air Forces on important targets-the German
high command pulled in the peripheral antiaircraft defenses
and protected its brightest jewels by the strongest
guards. This centripetal concentration was assisted geographically
by the overrunning of France by the Allies, by
the small casualties suffered by the German flak personnel,
and by the maintained production of antiaircraft guns and
other materiel.
DEFENSES OF BERLIN
In June 1944 the defenses of Berlin consisted of 400
heavy guns, most of these being the famous 88mm dualpurpose
gun, and 400 automatic weapons. At the time of
I the occupation by the Allies, 785 positions for heavy guns
I\'ere sighted, most of these having been occupied. Included
I\'ere 88 different battery positions, varying from the nor-
Inal 4-gun battery to "grosse batterien" of 16, 18, 22, and
24 guns. This defense stretched for 35 miles east and west
and 33 miles north and south. This was probably the only
area type defense in Germany. The disposition of the guns
seemed to conform to the shape of the city itself rather than
to the industrial complex contained therein, as was the
usual practice. The actual gun density per square mile at
Berlin was considerably less than at many industrial targets,
such as Schweinfurt and the synthetic oil plants, although
the total number .of guns exceeded those at many precision
targets.
In the center of Berlin there were three flak towers, each
having four 128mm twin mounts. About 40% of the remainder
of heavy guns were high performance 88mm (Flak
41) guns rather than the older 88mm (Flak 37). This new
gUn had a muzzle velocity of 3350 feet per second and a
maximum effective slant range of 13,200 yards. These high
performance guns were emplaced in the inner ring close to
the defended objectives.
This area defense of Berlin was probably established to
f~lfilI the mission of stopping the intensive night operatIons
of the RAF with its incendiary bombs. i\lanv of the
gUns were sited merely for barrage 'fire. Howe\'er: for the
number of guns this was not the best defense against our
daylight bombing, in which the planes approached within
a narrow sector. This broad defense permitted our aircraft
to attack and withdraw along routes which denied roughl\'
tWO-thirds of the guns the opportunity to engage.
lieutenant Colonel Gregory in his article on "Flak Intelligence
l\lemories" in the l\lay-June issue of the JOURXAL
st:lled: "The number of guns at Schweinfurt rose sharply
alter our first attack on the ball-bearing plants. Further, in
less than a vear the number of defendino guns on three
, 0
large oil targets rose from 270 to 1000 guns. Before VE-day
there were over 700 guns at an oil plant near Merseburg."
Certainly as our bombers went deeper into Germany they
were met by heavier flak of deFenses, the deFense of course
being in k~eping with the importance of the target.
TIlE DEFENSE OF HAi\IBURG
One of the best planned antiaircraFt defenses in Germany
was that of Hamburg. The largest seaport in Germany,
with a prewar population of 1,800,000, Hamburg
was the center of large commercial and manufacturino in-
.':)
terests. Among profitable targets in the city were oil refineries,
tank farms, naval dry docks, wharFs and cranes,
submarine pens, bridges, railway shops, freight yards, and
large storage areas. AFter heavy raids in early 1943. the
area defense of the eI:uire city was abandoned in fa\'or of
,defending a group of high p~iority installations. The batteries
were drawn in toward a defended zone roughly eggshaped,
in size 6 by 10 miles with the long axis nearly east
and west. This is shown in red on Figure 1. At the time of
maximum defense, in the late summer and fall of 1943, 398
guns were emplaced in the deFenses of the city, 278 of
88mm, 104 of 105mm, including 6 railway batteries, and
8 twin mount 128mm guns on the flak towers. These were
sited in 45 different positions, varying from 4 to 20 guns.
The defense of Hamburg is shown in Figure 1, superimposed
in red on a rough map of \Vashington. A proposed
defensive zone, somewhat analogous to the Hamburg zone,
is shown for \Vashington, this to include most of the government
buildings, the Pentagon, the bridges over the
Potomac, the main airfields, and the \Vashington and Potomac
freight yards. In order to equalize somewhat the defended
areas, the defense of Hamburg has been rotated
75° clockwise.
The basic assumptions made by the Germans regarding
altitude and speed of Allied aircraft were too high, as the
defenses were based upon an estimated ground speed of
325 miles per hour and an altitude of 26,200 feet. The
initial bomb release line, which for these assumptions equals
6500 yards, is shown in red on Figure 1. Both RAF and
AAF attacks were at airspeeds of 240 to 250 miles per hour,
and at altitudes of from 20,000 to 26,000 feet.
PLAX OF DEFEXSE
The German plan of defense consisted essentially of a
main or outer ring of guns at or near the bomb release line,
and an inner ring near the edge of the defended zone. In
the Hamburg-\Vashington defense of Figure 1, it is seen
that the main ring consisted of 17 positions with 30 batteries
and 176 guns, most of these being the older 88mm
guns. The inner gun ring consisted of 7 positions with 13