Ellsworth American. [volume] (Ellsworth, Me.) 1855-current, 1917-05-30
BENDS IN BIG GUNS
Their Weight Gives Some of Them
a Curvature OF the Spine.
DRooP AT THEIR MUzzLEs.
In Some Cases the Flexurs 10 Great
Enough, il Not Allowed Fer. to Affect
the Accuracy Of the Weapon-How
the rscce Is Corrected.

The newest American dreadnaughts
are to lie armed with sixteen inch RI
| ties, and the lay takes it as a 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 more exacting
engineering problem than the fourteen
inch weapon, and just because OF its
greater length and girth and weight IT
! Is a more difficult piece to make pre-
| else In Its action. The bigger the gun
the more ii is prone to develop trou-
blesome characteristics, and the ord
nance engiaeer 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 $4,000. 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 couple
OF hundred rounds.
1t must be remembered that a six
teen inch shell weighs about a ton
TO be exact. 2.loo pounds-and the
powder impulse exerts sufficient en-
ergy back OF the projectile to start 1t
from standstiil and to send 1t bur
Ting from the weapons muzzie ut a
velocity of 2,Soo feet second, It would
not do TO have that speeding shell Jam
In the bore of the rife, because IL sud
denly arrested 1t would probably frac.
ture the weapon If it did not cause a
Sraver 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 As caliber is
forty-fFe 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 girders. and their power TO resist
bending or reformation depends es
seatially upon the strength OF the ma
terials employed and the distribution
or 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 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 muzzles us much ms half
or three-quarters Of an inch, and this.
IL not realized and allowed for In sight
ing. VIII 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 II the rife has a 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-
amcter 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 lii of the gun or to impair
its range, provided the sights are ad-
justed TO 1t. But there is another In
fiuence at work which tends to affect
this droop and to cause it to vary some
hundretlths Of an inch from time to
time. This is the weather. For In
stance, gun will droop when the sun
shines tiercely 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 tanning 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 so 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 20
REINFORCED to check drooping?" The
bureau Of ordnance has resorted to a
very simple expedient in correcting this
| curative
| The deformed weapon Is simply TO.
| lated in the recon sleeve Of the mount
until the underside Of the rifle is up
| permost. The muzzle then, instead of
| dipping actually, 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 straightens out the
piece.-New York Sun.