The daily banner. (Cambridge, Md.) 1897-2008, 1917-05-01
BENDS IN BIG Guns
Their Weight Gives Some of Them
aCurvature of the Spine.
DROOP AT THEIR MUZZLES.
In Some Cases the Flexure Is Great
Enough, if Not Allowed For, to Affect
the Accuracy o, tho Weapon-How
the Defect Is Corrected.

In Some Cases the Flexure Is 1rea'
Enough, if Not Allowed For, to Affect
the Accuracy o, tho Weapon-How
the Defect Is Corrected.
The newest American dreadnaughts
are to be armed with sixteen inch RI.
fles, and the laymun takes 1t as mat
ter of course that these monster weap-
ons are merely bigger brothers OF the
fourteen inch gun. But this ohhand
conclusion Is decidedly at fault. The
sixteen inch gun is a more exactins
engineering problem~than the fourteen
inch weapon. and just because OF Its
greater length and girth and weight II
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
ly taxed In order to neutraliZe or to
minimize these inherent tendencies.
To begin with. the sixteen inch
gun, without its mount, represents ar
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 MOI
capable Of standing up 10 its worb
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 q ton
to be exact. 2.100 pounds-and the
powder impulse exerts sufficient en-
ergy back of the proJectlle to start 1t
from standstill and to send 1t hur-
Ting from the-weapOn muzZle at
velocity Of Q. 500 feet n 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-
ture the weapon If 1t did not cause
graver disaster Therefore the ord
nance engineer must see that the path
represented by the bore Is as nearly
straight line as 1t Is mechanically
,.and physically possible to make It,
\ twelve inch gun of 45 caliber Is
forty-tivc feet long. and except Mt the
single supporting point the heavy mass
of tie 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
Sentially upon the strength of the ma
te.'ialS employed and the distribution
%. 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
shuoting accuracy. but in time the
Weapcn becomes Il source of danger to
its own people.
The weight of some of the biz guns
HOW i'll use III the navy causes them to
droop at their muZZles us much as half
or three quarters of an inch, and this,
if not realized and allowed for in sight.
ing. Will make tie shooting inaccurate.
the inaccuracy increasing with the
length of range. In fact, the projec.
tile OH leaving the gun is directed by
the last six feet of the muZZfe That
is to say that if the rifle has a droop
the shell follows the curvature instead
Of taking the line assumed by the gun
pointer ut 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
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 adj
justed to it. But there Is another in.
fluence 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, gun will droop when the sun
shines fercely 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 stnl 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
reforming effect as heretofore. 1t may
be asked. What about the other guns
now in service that have not been sc
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-
tated in the recoil sleeve Of the mount
until the underside of the rife 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
niece New York SIM