The Butler County press. [volume] (Hamilton, Ohio) 1900-1946, 1917-03-09
BENDS IN BIG Guns
Their Weight Gives Some of Them
a Curvature of the Spine.
DRO0P AT THEIR MUZZLES.

In somo Cases the Fiexure is Great
Enough, IL Not Allowed For, to Affect
the Defect Is Corrected.
The newest American dreadnaughts
are to be armed with sixteen inch RI
fles, and the layman takes 1t as Il mat
ter Of course that these monster weap-
ons are merely bigger brothers OF the
fourteen inch gun. But this offhand
conclusion is decidedly at fault. The
sixteen inch gun is a more exacting
engineering problem than the fourteen
inch weapon, and just because of It's
greater length and girth and weight 1t
Is a more difficult piece to make pre-
else In It's action. The bigger the gun
the more 1t Is prone TO develop trou-
blesome characteristics, and the ord
nance engineer has his cunning heavi-
ly taxed In order to neutralize or to
minimize these inherent tendencies.
To begin with, the sixteen inch
gun, without its mount, represents an
outlay of $175,000, that being the price
paid for the materials used and the
skilled workmanship Unless fabricat-
ed with exquisite regard to accuracy
the weapon is neither safe to fire nor
capable Of standing up to its work
during relatively short active career,
measured by something like a couple
of hundred rounds.
1t must be remembered that six
teen inch shell weighs about a ton
to be exact, 2,100 pounds-and the
powder impulse eXerts sufficient en-
ergy back of the projectile TO start 1t
from a standstill and to send 1t hur-
Ting from the weapons muzzle at q
velocity Of $500 feet a second 1t would
not do to have that speeding shell jam
In the bore of the rifle, because If sud
denly arrested 1t would probably frac-
,ure the weapon If 1t did not cause a
graver disaster. Therefore the ord
nance engineer must see that the path
represented by the bore is as nearly
a straight line as it is mechanically
and physically possible to make 1t.
A twelve inch gun Of 40 callber is
forty-five feet long, and except at the
single supporting point the heavy mass
of the extended weapon is without any
sustaining help. These monster pieces
of ordnance are virtually single pivot
ed gtrders, and their power to resist
bending or reformation depends es-
sentially upon the strength Of the ma
terials employed and the distribution
Of the mass. Clearly, then. the big
ger the rifle the greater becomes the
disposition to droop toward the muz-
zle, and not only does this impair the
shooting accuracy, but In time the
weapon becomes n source of danger to
its own people.
The weight of some OF the big guns
now in use in the navy causes them to
droop at their muzzles as much as half
or three-quarters of an inch, and this,
If not realized and allowed for in sight
ipg, win make the shooting inaccurate,
the inaccuracy increasing with the
length Of range. In fact. the pro1ec-
tile on leaving the gun IS directed by
the last six feet of the muzzle. That
Is to say that if the rife has a droop
the shell follows the curvature instead
of taking the lire assumed by the gun
pointer at the telescope sight.
The bureau Of ordnance In Washing
ton has been working at this problem
as guns have grown in length and di-
ameter Of bore At the present time
the great fourteen inch weapons have
an aDpreciable drOOp of only IS of an
inch. This droop IS not enough to en-
danger the life of the gun or to impair
Its range, provided the sights are ad-
tusted to it. But there is another in
fiuence at work which tends to affect
this droop and to cause it to vary some
hundredths of an inch from time to
time. This is the weather For in
stance a gun will droop when the sun
shines nerceiy Upon RS um.er sI1a.