Improvements in Projectiles.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Projectiles.
We, CHARLES, KRNKA, of 44 Kalkova, Trida, Kral, Vinohrady, Prague,
Bohemia, Engineer, and WILLIAM HEBLER of Küssnacht, Schwyz, Switzerland,
Professor, 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 :—
As is well known several causes detrimentally influence the velocity of a
projectile through the air. One of the chief of which is the resistance of the
atmosphere. This resistance arises from two causes viz. :-
(1) The condensation or compression of the air strata immediately in front of
the projectile, and,
(2) The formation of a vacuum immediately behind the projectile.
To overcome the 1st form of resistance, the front or nose part of steel-mantled
or cased projectiles, for portable fire arms, has been finely pointed and the
cylindrical part has been reduced down to 5 millimeters in diameter.
The diameter of the projectile cannot very well be reduced further owing to
the fact that rifles cannot, as yet, be made with barrels of a smaller bore than
5 m.m. The usual bore for fire-arms is from 5 to 8 millimeters.
Very little has, as yet, been attempted in the way of reducing the resistance
under the 2nd head. In fact, few persons have, heretofore, troubled themselves
very much about it.
Our invention is mainly designed to diminish, as far as possible, the resistance
under both of the above heads.
In carrying out our invention we make the projectile pointed at both ends and
with an air channel or passage through it.
If only one part of the combination is used, only a partial success is obtained.
For example, if the projectile, whilst being pointed at one end ouly, is made
with a central air passage through it, then, notwithstanding the fact that there is
a decided improvement in the velocity, there is still a vacuum formed at the back
of the projectile corresponding to the thickness of its ring shaped bottom. And if
the projectile is made with pointed ends but without the air passage a vacuum
will still be formed. It is only by combining the air passage with the pointed ends
that the vacuum can be effectually destroyed.
On the annexed drawing, two of the new projectiles for 5-8 m.m. rifles are
shown in section. The projectiles, which are very much enlarged, are each shown
with the conducting sabot and a part of the empty cartridge.
In Fig. 1 an externally steel-cased projectile L is shown.
In Fig. 2 the projectile L is shown as lined internally with a tube R.
M is the steel casing. g the lead. H the cartridge. S the sabut and s a small
projection on the sabot.
If the projectile, Fig. 1, is fired the sabot S, with its projections, is, on leaving
the mouth of the barrel, immediately separated from the projectile.
As the projectile passes through the atmosphere the air in its front passes
easily over the tapered nose and flows rapidly over the tapered back part, and, at
the same time, an air current passes through the central passage.
As no vacuum is formed in the rear of the projectile and as it cuts its way with
very little resistance through the air, it follows that a very great velocity is
attained.
The sabot is made of paper or such like.material and has for its object to move
forward the projectile without loss of gas and to prevent it oscillating. In order
that the sabot may do this effectually it is made to embrace the tapered back
part of the projectile and the projections, or s¹, is made to fit into the passage L¹.

page_text: The projections of the sabot S' (Fig. 2) is slightly different from the pro-
jections (Fig. 1) as it is tapered so as to fit into the trumpet shaped enlargement
at the lower end of the passage L' (Fig. 2). By making the passage L' with
the enlargement the projection is prevented from biting into it and is therefore
caused to instantly free itself from the projectile when it leaves the gun.
The lead y is, preferably, as shown, entirely enveloped on the outside by the
steel or other metal casing.
In order to give the projectile the necessary rotation it is made with a cylin-
drical guide-roll m, over which the neck of the cartridge H passes.
The new projectiles, when made of only 5 m.m. diameter, are so thin that they
are very apt to be altered in shape either when passing along the barrel of the
gun or at the moment of impact. To give them more rigidity and stiffness the
internal tube R is fitted in the
passage L.
Instead of being formed of lead covered with a steel casing the projectile can
be made throughout of steel or other metal.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is:-
1. A projectile made with a longitudinal passage through it for diminishing the
resistance of the air, substantially as hereinbefore set forth.
2. A projectile having a longitudinal air passage through it and a stiffening
tube fitted in the passage, substantially as hereinbefore set forth.
3. A projectile tapered at both ends and made with a longitudinal air passage
through it, substantially as and for the purpose herein before set forth.
4. The projectile claimed in Claim 1, combined with a sabot having a projection
which enters the end of the air passage, substantially as hereinbefore described
and shown on the drawings annexed.
Dated this 10th day of October 1893
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.