Improvements in Projectiles or Aerial Torpedoes, and in Guns for Throwing the same.
Year: 1896

page_text: Date of Application, 13th Oct., 1895-Accepted, 14th Nov., 1896
COMPLETE SPECIFICATION.
Improvements in Projectiles or Aerial Torpedoes, and in Guns for
Throwing the same.
I, LOUIS GATHMANN, of 44 Lincoln Avenue, Chicago, Illinois, United States
of America, Mechanical Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to a projectile or aerial torpedo, of novel construction and
to a gun also of novel construction for throwing the same; the object of the
invention being to enable a projectile or torpedo having, a shell of a minimum
weight and containing a maximum of explosive material to be safely thrown,
accurately a greater distance than has heretofore been possible.
As my invention relates solely to the throwing of a projectile which is destructive
by reason of the explosion occurring upon impact as distinguished from a projectile
which is effective by reason of its power to penetrate and shatter an object into
which it is thrown, I do not necessarily employ as great a muzzle velocity as such
solid projectile or explosive shell requires. One object of my invention, however,
is to enable the throwing of a torpedo or explosive projectile safely, or without
danger of premature explosion, and with a greater muzzle velocity and consequently
to a greater distance than has heretofore been found practicable and safe. The
chief fault of projectiles of the common construction is that they require a very
heavy shell and consequently can carry a relatively small amount of explosive
material.
I attain the objects above stated as follows: First, I provide a gun whose bore
at or near the muzzle is of practically the same diameter as the shell, but of
greater and preferably of gradually increasing diameter from its contracted portion
back to the powder chamber, thus providing an annular space around the shell into
which the pressure generated by the explosion of the expelling charge may pass
freely, thus exerting a compressing force upon the shell sufficient to prevent
its bulging or jamming under the pressure exerted behind and within it. The gun
is preferably rifled throughout, except in the powder chamber; the rifling being
of uniform twist, but necessarily, because of the tapering bore, of, varying depth.
Second: I provide a torpedo having relatively a much larger amount of explosive
material to its total weight than has heretofore been employed with guns fired by
a powder charge, and such projectile I preferably provide with projections or
spiral ribs registering with the rifle grooves of the gun. I also provide a
detonating cartridge located interiorly of the shell of the torpedo and surrounded
by the explosive material thereof, and which is adapted, upon the striking of the
torpedo against an object, to be exploded and thereby explode the torpedo. The
shell of the torpedo is open at the base and may be made thin as above stated,
because with my improved gun, the pressure of the expelling charge within the
torpedo is counterbalanced by the external pressure in the space surrounding such
shell, but the detonator is necessarily made with a shell having a sufficient strength
to withstand the full crushing action of the powder charge.
It is a well known fact that some highly explosive materials, notably wet gun
cotton, will not explode by heat, by applied pressure or by ordinary concussion
and therefore I am enabled by my improvements to use large masses of such high
explosives without danger of premature explosion and with the utmost certainty of
proper delivery from the gun.

page_text: In the accompanying drawings I have shown my improvements in the preferred
forms and also certain modifications as to features thereof.
Figure 1 is a longitudinal section of the gun; the torpedo being shown therein
in elevation and the powder charge indicated.
Figures 2, 3 and 4 are transverse sections of the gun on corresponding lines of
Figure 1.
Figure 5 is a transverse section of the gun on a larger scale with the projectile
therein shown also in transverse section, and
Figure 6 is a similar view of the gun, the outer end of the projectile showing
therein in elevation.
The section lines of Figures 5 and 6 correspond substantially to the sections
shown in Figures 2 and 4.
Figure 7 is a longitudinal section of the projectile.
Figure 8 a rear elevation thereof;.
Figure 9 an enlarged broken sectional elevation through the rear end of the
torpedo ;
Figure 10 a sectional elevation through the middle portion of the torpedo; and
Figures 11, 12, 13 and 14 show modifications in the form of the projectile gun,
Figures 11 and 13 being broken transverse sectious through the gun near the
breech, and Figs. 12 and 14 being similar sections near the muzzle showing the
front end of the torpedo in elevation.
In carrying out my invention I propose to construct a gun capable of carrying a
torpedo charged with several hundred pounds of highly explosive material, say wet
gun cotton, for a distance of several miles. I prefer to construct the gun of a
calibre proportional to the desired range and the gun may be made of any of the
well known materials and disposed in well known ways but need not be nearly so
heavy as guns adapted to fire solid shot or shells which are effective by penetration.
In fact, it is one of the objects of my invention to construct a gun which will be
much lighter than guns of the character last above named, so as to enable the
arming of light cruisers, gun-boats or torpedo-boats and to make such lighter
vessels as efficient as a modern ironclad or battle ship. The barrel of the gun is
marked 15 and its breech may be closed by a breech block 16 having the usual
means for exploding a charge of powder coutained within the powder chamber
adjacent to the breech block. This powder chamber is usually smooth and of
slightly greater diameter than the bore of the gun at the iuner end of the powder
chamber.
From the powder chamber to the muzzle, the gun has in the preferred construc-
tion a hore of uniformly decreasing diameter and of greater diameter than the
shell of the torpedo, except at or near the muzzle, whereat the bore is of
practically the same size as the external diameter of the shell. By this means an
annular space is provided around the shell 17 of the torpedo, said space gradually
decreasing from the powder chamber to the muzzle. The gun is preferably rifled
from the front end of the powder chamber to the muzzle, the rifling being indicated
at 18 and such rifling is of uniform twist, and the lateral distance from the bottom
of one groove to the bottom of a groove directly opposite is equal throughout the
gun; the grooves being shallow at or near the powder chamber and of increasing
depth toward the muzzle, as clearly shown in the sectional views 2, 3 and 4 and in
slightly exaggerated scale in Figures 5 and 6.
a
The torpedo has a cylindrical shell 17 thin at its rear end and slightly increasing
in thickness toward its front end, the additional thickness being, of course, added
upon the interior of the shell, the exterior diameter being uniform. The front
end of the shell is tapered and has the usual opening closed by the plug 19. The
shell of the torpedo is provided, as shown in Figures 1, 5, 6 and 8 with spiral
ribs 20, and adapted to the rifle grooves for imparting an axially rotating movement to
the torpedo. The explosive material is packed in separate metallic shells or cartridges
having the cylindrical bodies 21 and the caps 22 which are tightly closed or hermeti-
cally sealed. The explosive material, indicated at 23, is prepared by pressing it into

page_text: discs or any other preferred forms. The cartridges enclosing the explosive material
are of a less external diameter than the internal diameter of the torpedo shell, so as to
fit loosely therein and provide a space 24, which is preferably filled with a liquid.
Near the rear end of the torpedo an asbestos plunger 25 is fitted into the shell of
the torpedo and preferably sealed with parafine. The shell is threaded at its rear
end and a metal spider having a threaded web 26 connecting its arms 27 is screwed
into the rear end of the shell, thus affording means for pressing the plunger and
the several cartridges tightly into the chamber of the shell previous to sealing.
The rear end of the shell is thus left open, except that it is crossed by the arms
of the spider and hence the force of the expelling charge acts upon the plunger to
break the seal and then upon the contents of the shell, transmitting the pressure
through the fluid body outwardly upon the shell and equally throughout its
length.
A detonator is enclosed in one of the cartridges and surrounded by the explosive
material. Said detonator is clearly shown in Figures 7 and 10 and consists of a
strong shell 29 having its forward end provided with a screw plug 30 and its rear
end closed by a cap 31. A metal tube or barrel 32 has a threaded engagement
with the plug 30 and contains a sliding plunger 33 which acts upon a percussion
cap 34 confined by a threaded plug 35, closing the end of the barrel 32. The
interior of the outer shell 29 is filled with dry gun cotton represented at 36 and
fulminate of mercury is enclosed in the outer end of the barrel 32 as iudicated
at 37. This detonator is of the usual construction, but in my invention I apply it
in a novel way, the same being enclosed in one of the cartridges containing the
wet gun cotton, whereby the detonator is protected from the heat generated by the
exploded powder charge, from the liquid enclosing the torpedo shell, and from
accidental or premature explosion by the packing of wet gun cotton about it.
It will be observed that the shell of the torpedo is open at its rear end or base,
thus allowing the force of the expelling charge to exert itself upon the plunger and
through it upon the mass of wet gun cotton. At the same time, the pressure caused by
the explosion of the expelling charge passes into the space around the shell, thus
counterbalancing the interior pressure and preventing the bulging of the shell and
its jamming within the gun. The shell of the detonator is of ample strength to
withstand the full pressure of the expelling charge without fracture, but will be
exploded by the concussion caused by the sudden stoppage of the shell upon
encountering an object.
The liquid body enclosed between the interior of the shell of the torpedo and the
exterior of the cartridges containing the explosive material prevents heating of the
cartridge shell and also serves as a medium for equalizing the pressure from within
and counterbalancing the pressure from without. The shell is made of increased
thickness toward its outer end, because there is at no time any external pressure
effective upon the tapering portion of the shell and hence the internal pressure upon
such portion of the shell is not compensated, except by this increased thickness,
and as the shell issues from the gun, increasing portions of it are subjected to the
internal pressure in the absence of counter pressure from without.
Of course, there will be slight waste of the force of the expelling charge, which
waste is due to the fact that there is an escape around the torpedo until the
front end of the latter reaches the muzzle wheu the full force is confined within
the gun.
Modifications of the above described construction may be made. I have shown soine
of said modifications in Figures 11 to 14 inclusive. In Figure 11 the gun is provided
with interior spiral ribs 38 which engage grooves 39 in the shell of the torpedo, the
spaces between the ribs serving to admit the pressure of the charge around the shell of
the torpedo. Figure 12 shows the same construction, the section being taken near
the muzzle of the gun and looking into the muzzle upon the front end of the torpedo.
lu Figure 13, the bore of the gun and the cross sectional form of the torpedo are
polygonal, an elevation of the front end of the torpedo being shown in Figure 14.
The view is taken near the muzzle of the gun and the torpedo is of the same

page_text: -calibre as the bore. In this construction the provision of mating ribs and grooves
is not present, but the twisting movement of the projectile is secured by its form
cc-operated with the similar form given to the bore of the gun. Further
modifications may be made both in the gun and torpedo. For example, the rifling
need not extend the entire length of the gun, and the bore need not be of uniform
taper.
It is essential to my invention, however, that there be provided a space
around the torpedo except at or near the muzzle and by a space, I mean,
such a contraction at the muzzle as would prevent unnecessary waste of the
*powder charge.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
.I claim is :-
An explosive projectile or torpedo having an open base and filled with a
material such as wet gun cotton, a detonator having a strong shell enclosed with
said explosive material and a gun for throwing said torpedo, said gun having a bore
of larger diameter than the torpedo, except at its muzzle, whereby to provide an
-annular space about the torpedo when in place in the bore of the gun, the gun
being rifled from the muzzle to the powder chamber and the torpedo having its
surfaces constructed to coact with such rifling, whereby to cause an axial rotation
of the torpedo when discharged and the interspace permitting the pressure of the
expelling charge to be exerted equally on the exterior and the interior of the
torpedo, in such manner that a torpedo having a maximum charge of the explosive
material may be used.
Dated this 13th day of October 1896
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.