The coastland times. [volume] (Mnateo [i.e. Manteo], N.C.) 1947-1959, 1953-07-31
SKY SCREEN TEAMS
HELP BIG GUNS HIT
ENEMY STRONGHOLDS

Washington. - The Army uses
sky screens to make doubly sure
its big guns deliver their out
going mail to the right enemy
bunker address.
The sky screens-optical eyes
sensitive to light conditions cou-
pied with electronic counters
measure the speed, or muzzle
velocity, of the Army's artillery
weapons.
With a battery of six guns of
the same caliber firing identical
powder charges, it cannot be as
sumed that all guns will develop
the same muzzle velocity. 1t still
is possible for one or more of the
guns consistently to fire short.
To compensate for this error
usually due to low muzzle velo-
city-the battery commander
uses the data made available by
the sky screens to make the nee
essary correction so that all guns
within his battery have the same
approximate point of impact.
This results in accurate mass
firings.
In plying their trade in Korea,
sky screen teams-o fficia ally
known as Ordnance Ballistic and
Technical Service units-bounc-
ed up and down Korea's noun
tains from one gun position to
another.
These Ordnance teams placed
their sky screens at two different
points forward and directly I'M
der the line of fire of the gun
being tested.
When all is in readiness, the
gun is fired and the first photo
electric eye detects the silhouette
of the passing projectile. AS the
projectile passes over the "eye",
it screens out or changes the in
tensity of the sky's light which
makes detection possible.
AS soon as the first intercept
it made, the "eye" sends a pulse
to the electronic counter. This
counter then remains in opera
ton until the second "eye" de-
tects the passing projectile when
another pulse is sent to the coun-
ter and causes it to cut off. The
recorded count is the time of
flight of the projectile between
the two sky screens.
Knowing the position of the
gun, the position of the sky
screens, and the time of flight be-
tween the two ''eyes," the ballis-
ticians then use this data to de-
termine the muzzle velocity of
the gun being tested.
Organized in teams of IL en-
listed men and two officers, the
ballisticians also cheek the inside
of the gun tube and the all
round efficiency of the guns.
This is done because wear and
tear on the gun tube and the fir
ing chamber after prolonged fir
ing will cause decrease in muz-
zle velocity and change the point
of impact of the outgoing mail.
Shells falling short of their
targets not only are less effective
but also cause artillery men to
expend costly ammunition that
otherwise could be saved.
When artillery men aim a gun
to fire at designated target, GER
tain varying conditions must be
compensated for in order to get
accurate and effective fire. Two
of the most important corrections
that must be made compensate
for existing atmospheric condi-
tons and muzzle velocities.
Unlike state-side operations,
where ballistic teams have the
weapons brought to them, sky
screen operators in Korea cover
the firing front. AS one of the
ballisticians put it, "the Eighth
Army could hardly afford to
keep hauling its artillery all over
Korea for ballistic checks"
Besides being ballisticians, the
team members also double as
housekeepers and maintenance
Emen. Entirely self-sufficient ex-
cept for food, the teams live in
their mobile vans and take care
of their own maintenance work.