IMPROVEMENTS IN ORDNANCE AND IN PROJECTILES TO BE USED THEREWITI!
Year: 1876

page_text: LETTERS PATENT to Hermann Emil Albert Hellhoff, of Mayence, Germany, at
present of 123, Chancery Lane, London, for the Invention of "IMPROVEMENTS
IN ORDNANCE AND IN PROJECTILES TO BE USED THEREWITI!."
Scaled the 6th April 1877, and dated the 27th December 1876.
PROVISIONAL SPECIFICATION left by the said Hermann Emil Albert Hellhoff
at the Office of the Commissioners of Patents on the 27th December 1876.
HERMANN EMIL ALBERT HELLHOFF, of Mayence, Germany, at present of
123, Chancery Lane, London. "IMPROVEMENTS IN ORDNANCE AND IN PROJECTILES
TO BE USED THEREWITH.”
This Invention relates,-
Firstly. To the construction of ordnance, or tube or apparatus for firing shells or
hollow projectiles charged with dynamite, nitro-glycerine, or nitro preparations; and
secondly, to the construction of such shells or hollow projectiles; and the object of
the Invention is,--
Firstly. To give such shell or projectile a gentle elastic but positive retaining
action within and on the discharge of the gun tube or apparatus so as to reduce the
shock or concussion to such projectiles.
And, Secondly. The manufacture of shells or hollow projectiles so as to allow of
the employment for the bursting charge thereof of dynamite, nitro-glycerine, or
analogous compounds or preparations having great explosive force, but extreme
sensitiveness to concussion and liability to explosion therefrom, such manufacture
not having been heretofore practically possible.
In carrying out this Invention I fit the projectile at the rear end of the gun tube
with spring appliances; these may be three or more steel springs formed with their
outer ends so bent or shaped as to assist in the revolving flight of the projectile.
The gun tube is at this place, that is, its rear portion, formed tapering off gradually
to a larger diameter towards the front, thus offering less endless frictional resistance
to the spring appliances on the projectile during the progress of the latter in the

page_text: gun tube; this taper portion may be formed by the insertion of a ring concentric
with the bore of the piece. The front part of the projectile is likewise fitted with
spring appliances which act as retainers and guides to the projectile during its
progress through the gun tube or apparatus for discharging same.
The projectile is constructed of a metal casing made up of various sections screwed
together. The first or front section of the metal casing has screwed thereon a
double domed cap or cover of thin metal fitted with knob formed as a pin or point
on its inner end. This first section of the metal casing is lined or cased with gutta
percha or similar material, and receives the charge of dynamite or nitro compound,
and at the rear end thereof are a number of helical springs, preferably five, which
support a wooden disc.
The charge of dynamite or nitro compound is compressed, so that about one and
two-third pints (one litre) will be of the weight of about four and a half pounds
avoirdupois (26 kilos.), and the requisite quantity constituting a charge is placed or
contained in a sack or bag of fabric "waxed" upon the inside so as to prevent any
abrasion or friction on the charge, and the upper end or portion of the sack is
pleated, creased, or folded so as to allow of expansion and contraction of the charge,
and is closed with a disc or plate. To the centre of the upper end of the sack is
secured a capsule containing a small portion of detonating compound. The charge
contained in the sack of waxed linen or other fabric is placed in the metal casing,
and the whole sack is by spring appliances so supported or held as to neutralize or
counteract concussion on the discharge of the projectile.
The rear end of the section of the metal casing containing the charge is, as before
mentioned, formed with screw thread, and the front end of the second section is
formed with a corresponding screw thread, and the other sections are united by
similar means, making up any required length of projectile; the last section is
formed with a tapered rear end. These supplementary sections are fitted with or
contain steel tubes, the number of the said tubes being preferably six; that is, five
arranged around a central one; these tubes are of varying lengths according to the
length of projectile. These tubes, which I call propelling tubes, are filled with flour
powder impregnated with nitro-glycerine.
According to another mode of igniting the dynamite charge I fit a detonating
composition to the rear end of the sack, and opposite this composition a suitably
supported weighted pin is arranged so as to be capable of being impelled forwards
when not retained or secured by a thread attached thereto, and carried along one of
the propelling tubes; when the thread has burnt through and the projectile hits an
object the pin will be thrown forward and pierces the composition and thereby
ignites the charge.
SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said Hermann Emil Albert
Hellhoff in the Great Seal Patent Office on the 18th July 1877.
"
HERMANN EMIL ALBERT HELLHOFF, of Mayence, Germany, at present of
123, Chancery Lane, London. 'IMPROVEMENTS IN ORDNANCE AND IN PROJECTILES
TO BE USED THEREWITH."
By means of this Invention I am enabled to use for projectiles in ordnance all
such explosive materials which detonate by blows or sudden heating, such as
dynamite, nitro-glycerine, litho-fracteur, dualine, gun cotton, and similar substances
which it has heretofore been practically impossible to employ for such purposes;
such substances of immense explosive power I use for the explosive charge in
projectiles of peculiar construction projected in ballistically, regulated, and adjustable
paths by means of a new application of projecting power against the surfaces to be
destroyed, such as battery armour or any other opposing body or surface.

page_text: The leading features of the construction of the ordnance made according to this
Invention are as follows:-
Firstly. The application of a new propelling force, the acceleration of which
increases evenly by equal increments from nothing up to any required maximum
value.
Secondly. The counteraction or neutralization of every shock or heating of the
explosive charge by the peculiar construction and peculiar acceleration.
Thirdly. The guiding of the projectile or mine in regular adjustable paths against
the aim by the peculiar construction of the appliances and by the peculiar
acceleration.
And, Fourthly. The utilization of the full destructive force of the explosive
charges by doing away with the strong walls of the projectile heretofore necessary
in the ordinary ordnance.
I will now describe one form of projectile constructed according to this Invention,
and illustrated by Figures 1 and 2, the former being a longitudinal section, and the
latter an outside view; it consists of three parts, the ignition chamber A, the main
body or cylinder B, and the cylinder strengthening part C. The ignition chamber A
has an outer protecting domed shield or cover a. b is a percussion mantle; the
shield a is made of sheet iron or other suitable material, and is screwed into the
female left-handed thread at the end of the cylinder B. a is a striking bolt or
knob fixed to the mantle b, and formed as a pin at its inner end; v is a safety pieco
between the shield a and the mantle b, the greatest distance between the shield a
and the mantle is about 2 inches. The latter carries on its inner side say five
percussion bolts B₁, B B B B, which are continued through band terminate in
hooks or eyes which carry the safety piece v, which latter consists of a plain elastic
piece of steel, which in the making of the mantle b is passed through the said hooks
or eyes and through the striking bolt a, and is held in tension by a peg outside the
shield.
The cylinder B is made of strong sheet iron, and has in front inner thread for the
attachment of the front part A, as before stated; c is a shoulder against which the
ring carrying the percussion cap or capsule X rests. The cylinder B carries in
front a centering ring g, to which are fixed, say, eight equidistant centering springs y
consisting of thin bent flat pieces of steel, so arranged that when bent about 3/1 inch,
give a resistance of about 22 to 33 lbs. ; they are bent about eight degrees against
the axis of the projectile for the direction of rotation.
16
The strengthened rear end of the projectile is formed with female screw thread d
for taking the propelling cylinder appliances; 8 arc, say, five spiral springs placed
equidistantly at the part C, and carrying a wooden disc f fitting easily in the
cylinder B. The latter is lined with a slightly vulcanized india-rubber casing, the
rear bottom of which is in the form of a bottle bottom, and rests on the wooden
disc f; the lining is not attached to the inside of the projectile. The charge bag or
sack is of canvas, waxed outside, whereby the friction is prevented, and the
nitro-glycerine prevented from filtering out through it. The charge bag filled with
one fourth the stipulated charge is inserted from above in the vertically placed
projectile, the charge is then gently compressed, if required, by means of a wood
plunger; the rest of the charge is then put in similarly, the weight of the charge in
the example here chosen is forty-four pounds of dynamite, eleven pounds at a time.
The upper end of the charge bag projects about 2 inches, and is then closed by means
of string tied around the wooden ring or disc z, which is hollow around the edge, as
shown to a larger scale at Figure 4, a certain amount of freedom for expansion is
allowed the charge; p is an india-rubber press ring on the lower face of the ring z.
The charge bag being closed, the ring z is made to rest on the shoulder c.
ring has a screw thread in the centre for carrying the cap or capsule X, which is
not put in till the projectile is to be used. The front dome or mantle and shield
are then screwed on. The percussion capsule X consists of a copper cap of the form
shown at Figure 3, and filled with a mixture consisting of 3 parts of chlorate of
The

page_text: potassium, and one of powdered gall nut, and covered with a thick ignition foil,
the capsule is on the side towards the charge lined with wool.
The next part of this Invention consists in the propelling cylinder for the projectile
which represents the driving force. The elements of the combination, now to be des-
cribed, have long been acknowledged as suitable for ballistic purposes, but as compared
with the driving force in ordinary ordnance, there were wanting both sufficient force
and the needed precision. I have succeeded in overcoming these defects. By means
of several cylinders, prisms, or cylinder sectors filled with powder under pressure,
I have by trials and calculations proved that a force and precision can be obtained
at least equal to that of rifled ordnance.
The appliances belonging to this part of the Invention consist of,-1. The pro-
pelling cylinders proper with parts belonging thereto. 2. The regulator for the
centre of gravity. 3. The retarding springs. And, 4. The rotation screw.
The propelling cylinders are, say, four in number (that is, for the example here
described), and are of sheet iron, about 28 inches long, and about 23%, inches inside
diameter. These cylinders are first well dipped in oil, lined with oiled blotting
paper to one-third of its height from the bottom, and then filled to that height with
a strong propelling composition by means of a press; then the rest is filled in the
same manner with ordinary composition, the cylinders are then bored out centrally to
about / inch, and the inside is then well oiled. These cylinders are shown in
longitudinal section at Figure 5, in cross section at Figure 6. Figure 9 is an outside
view of this arrangement. They are then at top and bottom placed in insulated
pieces and, and firmly fixed therein; these pieces are short wooden cylinders
with as many cylindrical holes as there are propelling cylinders, in this case four; they
are lined and bound with iron, but in such a manner that there is a free thin outer
wooden mantle acting as heat insulator. The iron ring on the piece is screwed
outside for screwing into the female thread d at the back of the projectile, Figures
1 and 2; the iron ring on the rear piece has a strong conical prolongation; both
iron rings have on their outer edges thin clay layers, the foremost one passing on
towards the cylinder Figure 1, the hind one only in the centre part situated to wards
the central ignition tube a; this latter consists of a rocket tube about 1 inch thick and
three inches long; each paper layer of the paper case is soaked in fuse composition;
this paper case with its open bottom piece is placed in the copper casing B, which again
is let into the middle part of the insulating ring, the copper casing takes hold of
the striker, which with four branches through four corresponding openings in
the casing, as in the propelling cylinder, takes into the latter. The fuse tube itself
is ignited through the small striker a by means of a train ignition of compound.
The conical prolongation of the insulating piece carries outside the ring m,
fitted with retarding springs; the lower part of the latter are in the axial direction
of the projectile and their upper part are bent off about 8 degrees for giving
direction of rotation below; they are cylindrical and of such a tension that when
compressed to about 5/8 inch each yields a resistance of about 33 to 44 pounds;
above they are thin and widened out in lancet form, the lancet-shaped surface forms
an angle and thus forms the running edge and the projectile steering edge k; I
thus obtain the following, viz, that these springs which at the same time serve the
most different purposes with their lower parts, act with a strong retarding force
when they pass through the cone ring of the ordnance tube hereafter to be described,
but simply act as central guides in the other or larger parallel part of the ordnance
tube. When loading, the ring m is drawn over the lower part of the springs. The
rear part of the conical prolongation of carries the rotation screw 7, Figure 7, of
the form shown, and the vanes of which are at an angle of about 8 degrees with the
gas current. The centre of gravity regulator n, Figure 8, consisting of a lead ring
cast upon a brass ring, which can be shifted as required and fixed in position on
the projecting parts of the propelling cylinder by means of set screws, as shewn.
According to another arrangement the projectile is fitted with bottom percussion
appliance; this is shewn at Figures 10 to 13, Figure 10 being a central longitudinal

page_text: section; Figure 11, a longitudinal section on line c, d, on Figure 12, which latter
is an end view; Figure 13 is a cross section. The principal modifications as
compared with projectiles with front ignition consist in that, firstly, the projectile
is charged up to the second cover (or the mantle & described with reference to
Figure 1). The elastic shield also in this case serving to take the shock against
the object aimed at or struck; secondly, in that the bottle-bottom-shaped bottom
of the inner lining is hollowed out to a much greater extent and is pierced for the
reception of the ignition bolt, which in charging is screwed into the elastically fitted
disc, a projection guards the bolt against every other blow except that of the per-
cussion bolt. The latter P, Figure 10, consists of a hollow cylinder about 6 inches
long, this great length being necessary for exact centering; its lower part is run in
with lead, it has its place in the central tube C between the propelling tubes aud
is behind formed with an eye passing through the partition ✗ of the centre tube C,
through this eye is passed a strong thread or touch cord which at its other ends is
fastened to a fixed paper tube carrying a composition pin which is ignited with the
propelling cylinders. This novel percussion bottom ignition combines with the
sure action of the igniter, also the greatest safeguard against accidents. The per-
cussion pin is not put in till loading, but the percussion bolt P is not released until
the central composition pillar is burnt; that is, after a great part of the flight has
been accomplished; on the other hand the weighted bolt P must by its great length
and greatest weight behind keep central in the tube and hit the percussion cap
centrally.
The ordnance or gun tube for shooting off the aforesaid projectiles I prefer to
make, as shewn at Figures 14 to 17, Figure 14 being an outside view of same;
Figure 15, a longitudinal section; Figure 16, an enlarged perspective part outside
view; and Figure 17, an end view; is the tube made of about 5/8 inch thick
The tube is
sheet iron, 10 feet 6 inches long and 9 inches inside diameter.
loaded at the breach and the part a, b, c, d, turns like a door on the hinges m, n,
so that the plane of opening forms with the horizon an angle of about 45 degrees,
the door is locked by means of screws passing through lugs u¹, u. About 8 inches
from the rear end there is fixed an inner retarding ring B, which has a height of
about 13/4 inches and a width of about 1/4 inches, the interior of the tube from the
mouth to the ring ẞ coated with a vulcanised india-rubber lining, which is cylin-
drical for about 8 feet from the mouth and about $/, inch thick, and from that
point tapers down to the ring B. This india india-rubber lining is coated inside
with 3 inch thick strongly compressed hair felt, well impregnated with an alum
solution to prevent its catching fire from sparks from the propelling cylinders. The
tube : carries outside a trunnion ring S with trunnion pivots, also "sight," &c., for
aiming; V is a breach-closing appliance consisting in a thin screw working in a
cross bar y, and pressed against the rotation screw in order to prevent the pro-
jectile from running back when working with high elevations of the ordnance.
The mode of working the above-described apparatus is as follows:-By ignition
of the ignition tube the small surface of the chambers containing composition is
first ignited, whereby the aforesaid paper casing is set fire to, Figure 5, and the
wood parts of the insulating piece which insulate the heat relatively to the pro-
pelling cylinders.
As the ignition of all the propelling cylinders is concentrated they become
ignited simultaneously.
First moment of the movement of the projectile.-The pressure of the firing
composition chamber presses the retarding springs gently into the ring B.
Figure 15, the first moment of inertia being overcome, the propelling cylinder
system commences to overcome the retarding pressure, which has a maximum of
about 30 pounds. The retarding springs are slowly turned by the tube ring while
the escaping gas current acts on the cones of the rotation screw and causes a
turning from down left to up right. At the ring ẞ the retarding influence is the
greatest, it gets weaker in a moment, as soon as the retarding parts of the springs

page_text: enter the clastic walls of the cone part of the india-rubber lining. The tightening
ring m, Figure 5, is pushed off when the springs pass through the ring ß.
Second mement of the movement of the projectile. The propelling cylinder
system is in the conical part of the india-rubber lining, the springs are still
retarding, but less and less as it passes through this conical part; as they pass
the ring they lay themselves over the rotation screw and guide the same
centrally.
Third moment of the movement of the projectile.—The latter is altogether in the
cylindrical part of the tube lining, the springs pass lightly along the walls of the
latter without retarding, together with the centering springs, the friction is almost
nothing. The propelling power acts exactly parallel to the axis of the projectile,
the latter obtains its full acceleration and full rotative velocity round its longi-
tudinal axis.
Fourth moment. In the moment the projectile leaves the mouth of the gun tube
the steering edges of the retarding springs pass about 3/4 inch beyond the projectilo
cylinder. I thus obtain a secure steering for the path in a similar manner to the
feathers on an arrow in this manner, that the point of the projectile must be
exactly in the tangent of the path of flight. The steering edges stand doubly
inclined against the air current, see Figures 5 and 9, the latter has thus no greater
surface opposite to it than necessary for the steering of the projectile, and the air
resistance is used for increase of speed of rotation. The springs thus fulfil four
objects, viz., the gradual overcoming of the moment of inertia (which at the same
time is also obtained by the mode of acceleration); secondly, the exact centering of
the propelling power; thirdly, the steering of the projectile; and fourtly, the
increase of the speed of rotation.
Fifth moment. As soon as the projectile or mine reaches its destination the full
moment of motion is applied to the knocking in of the knob with its point (the
knob stands out so far that it always strikes the object first, even when hitting at
an angle of 60°), the time for pressing in the shield and mantle suffices to explodo
the mine, which thus is close upon the object aimed at.
The greatness of the action of this projectile depends entirely upon the fearful
explosive force bottled up therein. As the awful power of the nitro-compositions
is known it is easy to calculate that the destroying power of a charge of dynamite
amounts to about twenty million kilogrammeters, or about 150 million foot pounds,
an effect which even the largest guns cannot even approximately attain.
As compared with the ordinary propelling power iny mode of applying it is just
the opposite as regards the initial velicity, whereas heretofore the initial velocity
is a maximum, and the velocity during the flight through the air resistance is
rapidly decreasing; the initial velocity is here at first nothing, and then increases
steadily and gradually up to the maximum, and it is this which is applicable to nitro-
explosives for artillery purposes.
Each of the propelling cylinders develops the required force for throwing a 100
pound shell, and accordingly by the combined systemn I obtain initial velocities
sufficient for enormous flights. The increase of propelling power can be obtained
by the contructor as required, and is almost without limit; it may be done in onc
of three ways, either the propelling cylinders may be increased in number to 5, 7, 9,
or more, or the absolute power of composition may be increased, choosing therefor
nitro-glycerine powder with sulphur; or lastly, the propelling cylinders may be
somewhat increased in length and divided into double chambers; if the chambers
of two corresponding cylinders are so placed that the chambers of one terminate
in the middle of the length of the other, then the steadiness of acceleration is
not interrupted even during the smallest possible space of time, see Figures 10
to 14.
And having thus described the nature of this Invention, and some modes of
carrying the same into effect, I declare that the dimensions and the arrangements
of details may be very materially altered and modified according to caliber and

page_text: other requirements without in any way departing from the nature of this
Invention.
In witness whereof, I, the said Hermann Emil Albert Hellhoff, have hereunto
set my hand and scal, this Twenty-third day of June, in the year of our
Lord One thousand eight hundred and seventy-seven.
H. E. A. HELLHOFF. (LS.)