The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1917-06-21
CURVATURE OF BIG GUNS
HOW IT IS TAKEN OUT
THE LARGER THE GUN THE MORE
DIFFICULT THE TASK TO
AVOID DIFFICULTIES.
(New York SUM

of course that these monster weapons
are merely bigger brothers of the IA
inch gun. The man in the street says;
The larger gun merely means so
much more metal and increased pro-
portions; it is a simple matter of ex-
pansion."
But this offhand conclusion is de-
cidedly at fault The 16-inch gun is
more exacting engineering problem
than the 14-inch weapon, and just be-
cause of it's greater length and girth
and weight it is a more difficult piece
to make precise in its action. The
bigger the gun the more 1t is prone to
develop troublesome characteristics,
and the ordnance engineer has his
cunning heavily taxed in order to neu-
tralze or to minimize these inherent
tendencies.
Cost a Fortune.
To begin with the 16-inch gun,
without its mount, represents an out
lay of $4,000, that being the price
paid for the materials used and the
skilled workmanship. Unless fabri-
Gated with exquisite regard to accur-
acy, the weapon is neither safe to fire
nor capable of standing up to its work
during a relatively short active ca
reer, measured by something like a
couple of hundred rounds.
1t must be remembered that 16-
inch shell weighs about tonic be
exact, POO pounds. and the powder
impulse eXerts sufficient energy back
of the projectile to start it from a
standstill and to send it hurting from
the Weapons muzzle at velocity of
$500 feet second. 1t would not do
to have that speeding shell jam in the
bore of the rifle, because if suddenly
arrested it would probably fracture
the weapon if it did not cause a grav-
engineer must see that the path rep
resented by the bore is as nearly a
straight line as it is mechanically and
physically possible to make it.
Gun Was Bent.
1t will be remembered that one of
the 12-inch guns of the battleshlp
Michigan was ruined some months ago.
The whole chase or muzzleward por-
ton of the weapon was blown up. An
investigation attributed the accident
to the untimely bursting of high eX-
plosive shell which was being fired;
but among a good many ordnance eX-
perts the belief persisted that the ac-
cident was primarily due to defect
in the gun, namely, that the weapon
was bent.
The layman will naturally wonder
how that ponderous 12-inch piece wa'
deformed. for certainly the weapon
was turned out by the naval gun fac
tory as straight as die. Well, if i
was bent the warping might have beer
brought about by the action OF the
sun. combined with what might be de
scribed as the fatigue of the guns
long body.
Weight Without Support.
! A 12-inch gun of 45-calibre is Al
feet long and except at the single sup
porting point the heavy mass of thu
extended weapon is without any sus
tanning help These monster pieces o
ordnance are virtually single pivotet
Orders and their power to resist bend
ing or reformation depends essentlall.
upon the strength Of the material
employed and the distribution OF TN
mass. Clearly, then, the bigger tn
rifle the greater becomes the DISPOSE
ton to droop toward the muZZle, ant
not only does this impair the shooting
accuracy. but in time the weapon pe
comes a source of danger to its owl
people.
The weight of some of the big gun
now in use in the navy causes them u
droop at their muzzle as much as nal
or three quarters of an inch, and this
if not, realized and allowed for in tn
sighting, will make the shooting mac
curate, the inaccuracy increasing witt
the length of range. In fact, report
from abroad during the present wa
declare that the projectile on leavin'
the gun is directed by the last six fee
of the muzzle. That is to say, that !
the rifle has a droop, the shell follow
the curvature intsead of taking tn
lime assumed by the gun pointer a
the telescope sight.
Difficult Problem.
The bureau of ordnance in WASH
ington has been working at this prob
lem as guns have grown in length an
diameter of bore. At the present tim
the great 14-inch weapons have an ap
preciable droop of only OBS of an inc
and this very slight bend in the tots
length of trifle over feet is du
alone to the natural elastic yleldln
of the material employed in the man
ufacture of the piece.
This droop is not enough to endan
ger the life of the gun or to impair II
range, provided the sights are adjus,
ed to it. But there is another influ
ence at work which tends to affect tn
droop and to cause it to vary SON
hundredths of an inch from time
time. This is the weather. For II
stance, gun will droop when the su
shines fiercely upon it's upper sic
Hill oil do iu oh