The sun., 1900-11-29

The New Nav, t2.iash cav.

INe NrW Nt'E bfEnfN ''"'
IN. now p.inch sun medc Tor ihe navy
has pfrduc~d something ~ y sensation IN ora
rnbc" cfolns ~ trial wa teruttrd list v""h
" nr"a y pfplcrtiic weighing 40 ppunds WIN y
mu,,le velocity ~ nc1fly 2joo foot tor a"c"hd'
or n"nfly 7,7" ioot-'"conda. witch makes IT,
In tho sense that " viii carry fnrthrst thr uost
powerful run IN tho world i'- maximum
range. nj m elevation ~ a. d"2rr"-. ~ cnlcn-
lai"1 by Maiot ingalls, Of IA" United StH'"'
Artillery, I. 222 mile,
Tho army l2-inch gun. found In our coast
forti0cation'. nrrs n LOO pound proicciil"
with n mulllo velocity ~ 2O!a foo'-s"cond7'
and of cour.c n much shorter range Tho
army i0-hch gun. rec"ntlv completed ~
Watcrvl!ct Arsenal l. expected 10 give 800
foot-scconds of muzale velocity To n projectile
weighing 2.370 pounds. ia maximum range.
according 10 Major Ingalls, will he ~ miles
tat an elevation 81 ~ degrees, No European
gun can compare with this IN muzzle energy.
These striking results In the navy gun have
been obtained by tho Use of very powerful
powder. snokeess. n longer barrel or bore
and a lighter proiectilo. let u' briefly consider
how these changes produced the effect desired
The fixed elements In any gun which affect
the muzzle velocity and maximum pressure are:
a. Calibcr. or diameter Of tho bore.
(2) Capacity OF the powder chamber which
holds the charge
(g Travel of the projectilo In tho bore.
az Weight Of the projectile.
The variable elements are:
~ Quality Of powder
(2 Weight OF powder charge
tN Density OF loading. that H. the relative
space occupied by a given weight Of powder.
N Rate Of powder combustion
In the same gum therefore. firing particu-
lar proJectile. with particular kind Of powder.
we may vary the muzzle velocity only by
varying the weight Of the charge. But In
designing new guns all the fixed elements
may be changed. In the case OF this
new gun tho caliber was established at IL
inches. but to obtain higher muzzlc velocity
tho designer was influenced by the following
considerations:
In the first plnce. the ravy smokeless powder.
according to Lieut.; Strauss, United States
Navy. Inspector OF Ordnance at Indian Head
Proving Ground, has proved excellent in quail
ity. and in the e-nch gun. 40 calibers long.
gave a muzZle velocity of over 5000 foot-sec-
onds, with II tons pressure; and II Is expected
that in the new 5O-caliber guns now building
1t will give the same or a greater velocity with
less pressure.
In the next place. the smokeless powders
nave tIic lcHldIhdDIc IIpptl'y VI eNlHt Sieut'i
velocitles and lower maximum pressures in
the bore than the old powders, This Is due
TO the fact that they are elow-burning powders.
and although the maximum pressure is less
the aggregate pressure on the projectile. while
1t is In the bore. is greater. consequently the
projectIle has higher velocity.
The longer a projectile remains in the boro
the longer the gases act on 1t. consequently
increased encth of boro (limted by friction
In the bore. and the time the powder takes
to be entirely corsimed) must give increased
velocity. Experiment has shown. however.
that beyond a certain point nothing is gained
by increasing the length of the gun: more
over, excessive length means great weight
and unwieldiness Of the piece The best length
Of bore depends on the powder and other con-
sderations. and has generally been determined
by calculation. in the large caliber guns as
II is too expensive TO test cxperimentally
Finally having obtained increased muzLle
velocity by the use Of a GOOD powder and by
increasing the length Of the bore. the pro-
jectllo mny tc made shorter. and st,ll be steady
in its fight. with n consequent further increase
in velocity. The length Of the proiectile is
determined Camons other considerations by
what IL necessary to prevent IL from "tum-
bling. or rather by what will keep its point
steady TO the front. on which condition its
accuracy largely depends But the greater
tho velocity the less the tendency 10 tumble.
hence a fast-moving projectile need not be
so long as a slow-moving one to obtain this
result But a reduction In weight OF pro-
jectile there being less matter TO novel still
further Increases the mu2zle velocity. and
this element is therefore also effective In giving
greater nluzzle velocity
To sum up. then. the new navy gun uses
an excellent smokelcss powder. giving high
velocities combined with low pressures: II 10
5o-caibers long (which is not excessivel. while
the army gun ia only 40: 1t fires an $50 pound
proiectile. while the Army gun fires one Of 600
pounds. and since the diameter is the same In
both the length of tho former is less
These are the main factors that determine
its great power: but. Of course. there are many
other elements involved. and the designer
did not find the problem so simple a. appears
from this brief explanation