Improvement in the Arrangement of Torpedo Screws.
Year: 1896

page_text: Date of Application, 31st Mar., 1896
Complete Specification Left, 8th June, 1896-Accepted, 11th July, 1896
PROVISIONAL SPECIFICATION.
Improvement in the Arrangement of Torpedo Screws.
1, FRANCESCO ROBERTO MAZZINGHI, Lieutenant in the Royal Italian Navy,
of Spezia, Italy, do hereby declare the nature of this invention to be as
follows:-
The present invention has for its object the improvement of the arrangement
and circumference of torpedo screws in such a manner that the motion of the
torpedo in the line of fire becomes more even and effectual.
Reference to the proposed method of carrying out the invention as illustrated on
the annexed drawing, shews:
Figure 1 the projection of the torpedo in a plane parallel with that which
passes through the shafts of both screws as arranged in the present invention,
a part of the construction is removed in order to bring out the mechanism more
clearly.
Figure 2 gives a section through the line A B of Figure 1.
Figure 3 is a projection of the hinder portion of the torpedo in a plane
perpendicular to that in which the shafts of both screws lie, and parallel with the
shaft of the torpedo.
.
The reference letters in the different figures are in all cases intended to refer to
the same parts of the torpedo in each.
Torpedoes as at present arranged by Whitehead and Schwarzkopf have two
screws fixed on the same shaft. This is an arrangement which unquestionably
gives rise to great disadvantages in two points.
(a) In regard to the velocity of the torpedo
(b) In regard to the trajectory of the torpedo.
To define the invention clearly in contradistinction to the present arrangement it
appears to be first of all necessary to refer more closely to these disadvantages.
(a) DISADVANTAGES IN REGARD TO THE VELOCITY OF THE TORPEDO.
As the two screws are placed at a very small distance from each other it results
consequently that the rear screw can only have a very limited effect as it works in
strongly disturbed water. The front screw also is situated very unfavourably for
effective action, as it also works in disturbed water for this reason viz., that the
relatively light parts of the rear portion of the torpedo in comparison with the
total length and velocity of the propeller, are not sufficiently long to keep pace
with the stream of water displaced by the forward portion of the torpedo.
Now it is generally known that the effect of a screw depends in no small degree
upon the method of afflux of the stream of water and therefore it is necessary
for constructors to let torpedo screws have very large diameters, because the
ends of the screw blades are considered to be the only parts really effective for
propulsion.
The extreme want of proportion between the total surface of the torpedo screws
and the maximum section of the torpedo is readily apparent.
The importance of the large diameter of screws entails proportionately strong
machinery and limits the number of revolutions per minute, moreover it is well
known from the case of the English ship Iris that important advantages in

page_text: olane of the length of the torpedo and two others, exactly equal to those described,
are attached in the perpendicular plane of the length of the torpedo.
With the arrangement of two side screws, as also with four the construction of
the Whitehead torpedo receives an essential change. It is this new arrangement,.
which signifies an important improvement, which represents the object of the
invention.
The technical advantages of the two side screws indicated by r and are the
following
The screws can be made of smaller diameter because their whole surface has an
effect upon the propulsion, and because it is not disadvantageously influenced by
currents of disturbed water moving in directions nearly parallel to the axis of the
torpedo.
It is therefore possible to augment the number of revolutions of the screw to the
immense advantage of the propulsion of the projectile.
The machines may be smaller and as a result the cost of maintenance will be less
and thus the torpedoes will have an extended circle of effect.
The screws are without influence on the horizontal line of the torpedo, if the
number of revolutions varies no effect is produced whereby the torpedo is diverted
and so could deviate from its course.
Moreover the rear portion of the torpedo is from 10 to 15 kilogrammes lighter
and in the mechanical arrangement more simple and proportionately more strong
than hitherto.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is :-
First. An arrangement in torpedoes in consequence of which the exactness of the
movement in the line of fire is increased and the propelling strength is better
employed, by reason of two of the shafts of the torpedo running parallel and from
their being equally distant from the torpedo shaft, with which they are in a plane,
the screw shafts m and n are driven in opposite directions by the cog wheels r
and r¹.
Secondly. By the arrangement according to Claim 1 through the introduction of
screws of smaller dimensions more favourable conditions for working as regards the
water are secured and a greater speed of propulsion attained.
Thirdly. By the arrangement according to Claim 1 another method of carrying
it out, differing from it by the use of four side screws symmetrically arranged and
in gear with the torpedo shaft, two of the screw shafts are in a horizontal plane,
and the other two in a perpendicular plane bearing screws attached and driven in a
similar way.
Dated this 6th day of June 1896.
FRANCESCO ROBERTO MAZZINGHI,
By Henry Skerrett,
24 Temple Row, Birmingham, Agent for Applicant.