|
Main
- books.jibble.org
My Books
- IRC Hacks
Misc. Articles
- Meaning of Jibble
- M4 Su Doku
- Computer Scrapbooking
- Setting up Java
- Bootable Java
- Cookies in Java
- Dynamic Graphs
- Social Shakespeare
External Links
- Paul Mutton
- Jibble Photo Gallery
- Jibble Forums
- Google Landmarks
- Jibble Shop
- Free Books
- Intershot Ltd
|
books.jibble.org
Previous Page
| Next Page
Page 20
The gun is smooth-bored and a full-sized projectile is a cylinder with
hemispherical ends, to the rear of which is attached a shaft having
metal vanes placed at an angle, which causes the projectile to revolve
round its longer axis during flight. A subcalibered projectile,
however, being of less diameter than the bore of the gun, has the
vanes on its exterior, and is held in the axis of the gun by means of
gas checks which drop off as the projectile leaves the muzzle. The
shock to the explosive is, of course, greater than in the full-sized
projectile, but the increase can be calculated, and so far a dangerous
limit has not been reached. From the fifteen-inch gun with a pressure
of 1,000 pounds per square inch and a velocity of about 800 f.s., a
range of 4,000 yards has been obtained at an elevation of 30� 20, with
a ten-inch subcalibered projectile, about eight calibers long and
weighing 500 pounds. This projectile will contain 220 pounds of
blasting gelatine. With improved full-sized projectiles weighing 1,000
pounds, a range of 2,500 yards will doubtless be obtained.
At elevations below 15� these long projectiles are liable to ricochet,
and what is now wanted is a projectile which will stay under water at
all angles of fall and will run parallel to the surface like a
locomotive torpedo. Such a projectile has yet to be invented; but I
have seen a linked shell, which has been experimented with from a
nine-inch powder gun, that partially meets this condition. It is made
of several sections united by means of rope or electric wire in
lengths of 100 to 150 feet. When fired all sections remain together
for some distance; the rear section then first begins to separate;
then the next, and so on. It is primarily intended to envelop an
enemy's vessel, and to remedy the present uncertainty of elevation in
a gun mounted in a pitching boat; but it is found that when it strikes
the water in its lengthened out condition, it will neither dive nor
ricochet, but will continue for some distance just under the surface
until all momentum is lost, when it will sink. This projectile is at
present crude, and has never been tried loaded, but it will probably
be developed into something useful in time.
I have confined my remarks in the foregoing discussion principally to
such methods of using high explosives in shells as have proved
themselves successful beyond an experimental degree, and practically
they reduce themselves to two, viz., using a sluggish explosive in
small quantities from an ordinary powder gun, and using any explosive
from a pneumatic or other mechanical gun. Naturally, the success of
the latter method will soon induce the manufacture of powders having
an abnormally low maximum pressure. There is undoubtedly a field for
the use of such powders in connection with an air space in the gun to
still further regulate the pressure; but nothing of this sort has yet
been attempted. Many methods of padding the shell have been devised
for reducing the shock in powder guns, but the variability of the
powder pressure is too great to have yet rendered any such method
successful. A method was patented by Gruson in Germany of filling a
shell with the two harmless constituents of an explosive and having
them unite and explode by means of a fulminate fuse on striking an
object. He used for the constituents nitric acid and dinitro-benzine,
and was quite successful; but the system has not met with favor, on
account of the inconvenience. The explosive was about four times as
powerful as gunpowder.
That the advantage of using the most powerful explosives is a real one
can be easily shown. The eight inch pneumatic gun in New York harbor,
with a projectile containing fifty pounds of blasting gelatine and
five pounds of dynamite, easily sunk a schooner at 1,864 yards range
from the torpedo effect of the shell falling alongside it.
This same shell, if filled with gunpowder, would have contained but
twenty-five pounds, and have had but one-ninth the power.
The principal European nations are now building armored turrets sunk
in enormous masses of cement, as a result of their experiences with
gun-cotton and melenite. The fifteen inch pneumatic projectile, which
I described as being capable of sinking an armorclad at forty-seven
feet from where it struck, would have been capable of penetrating
fifty feet of cement had it struck upon a fortification. It was not
only a much larger quantity of high explosive than Europeans have
experimented with, but the explosive itself is probably more than
twice as strong as their gun-cotton and five or six times as strong as
their melenite. In the plans of Gen. Brialmont, one of the most
eminent of European engineers, he allows in his fortifications about
ten feet of cement over casements, magazines, etc. It is evident that
this is insufficient for dynamite shells such as I have described.
At Fort Wagner, a sand work built during our war, Gen. Gillmore
estimated that he threw one pound of metal for every 3.27 pounds of
sand removed. He fired over 122,230 pounds of metal, and one night's
work would have repaired the damage. The new fifteen inch pneumatic
shell will contain 600 pounds of blasting gelatine, and judging from
the German experiments at Kummsdorf, which I have cited, one of these
fifteen inch shells would throw out a prodigious quantity of sand;
either 500 pounds to one of shell, or 2,000 pounds to one of shell,
according as the estimate of Gen. Abbot or of Capt. Zalinski is used.
The former considers that the radius of destructive effect increases
as the square root of the charge; the latter that the area of
destructive effect for this kind of work is directly proportional to
the charge.
Previous Page
| Next Page
|
|