The Meeker herald., 1917-06-30
BENDS IN BIC GUNS
Their Weight Gives Some Of Them
Curvature Of the Spine.
pRooP AT THEIR MuzzLEs.

Enough, IL Not Allowed For, to Affect
the Accuracy Of the Wsapon-Hew
the Defect 10 Corrected.
The newest American dreadnaughts
are to be armed with sixteen Inch RI
ties. and the layman takes 1t US mat
ter of course that these monster weap-
ons are merely bigger brothers of the
fourteen inch gun. But this onhand
conclusion is decidedly at fault. The
sixteen inch gun is a more exacting
engineering problem than the fourteen
inch weapon. and just because of Its
greater length and girth and weight 1t
is a more difficult piece to make pre-
else in its action. The bigger the gun
the more 1t is prone to develop trou-
blesome characteristics, and the ord
nance engineer has his cunning heavi.
~ taxed in order to neutralize or to
To begin with. the sixteen inch
gun, without its mount, represents an
outlay of $175.OOO. 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 couple
OF hundred rounds.
1t must be remembered that a six
teen inch shell weighs about ton
to be exact, 2,1OO pounds-and the
powder Impulse exerts sufficient en-
ergy back of the projectile to start 1t
from standstill and to send 1t hur-
Ting from the weapons muzzle at a
velocity of 9, 800 feet second. 1t would
not do to have that speeding shell jam
In the bore of the rife because II sud-
denly arrested 1t would probably frac-
ture the weapon II 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 1t is mechanically
and physically possible to make it.
A twelve inch gun OF 40 caliber is
forty-tive feet long, and except mt 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
cd girders, 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 rife the greater becomes the
disposition to drOop toward the muz-
zle, and not only does this impair the
shooting accuracy, but In time tho
weapon becomes a 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 muzzes as much as half
or three-quarters Of an inch, and this.
il not realized and allowed for In sight
ing. will make the shooting inaccurate,
the inaccuracy increasing with the
length of range. In fact, the projec-
tile on leaving the gun Is directed by
the last six feet OF the muzzle. That
is to say that if the rifle has droop
the shell follows the curvature instead
OF taking the line 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 appreciable 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-
justed to It.. But there is another in
fuence at work which tends to affect
this droop and to cause it to vary some
hundrelths of an inch from time to
time. This is the weather. For in
stance, a gun will droop when the sun
shines fiercely upon its upper side,
while the under side Is shaded. But
so long as this total detection does
not exceed half an inch there is no dan
ger, Of the shell jamming In passing
along the slightly curved bore.
In the latest of our big naval weapons
this droop has been still further re-
duced by extending the jacket or hoop
ing further out over the forward part
of the gun. This serves to stiffen the
gun 30 that the sun has not as much
deforming effect as heretofore. 1t may
be asked, what about the other guns
now in service that have not been 80
REINFORCED to check droOping?" The
bureau of ordnance has resorted to a
very simple expedient in correcting this
curative.
The deformed weapon is simply ro-
tated In the recoil sleeve Of the mount
until the underside Of the rife is up
permost. The muzzle then, instead of
| ,j;ppfn1 actnaIly is curved skyward.
In time the natural elasticity of the
metal asserts itself, and the over
hanging weight of the outstretched
muzzle gradually presses the chase
downward and Strengthens out the
piece.-New York Sun.
Wall Balanced Tires.