Year: 1898

page_text: I, RUDOLF COUNT WESTPHALEN, of 33A, Rennweg, Vienna III, in the Austrian
Empire, Gentleman, do hereby declare the nature of this invention to be as
follows:-
This invention relates to that class of propellers, which act on the principle
of the screw and are secured to shafts parallel to the keel of the vessel,
the said invention having for its object to reduce the slip, caused by the fluid
nature of the medium in which the propeller revolves.
It has already been proposed for this purpose to provide the blades of screw
propellers with transverse ribs, whereby given elements of the surface enveloping
the blades are arranged at variance with the helical surfaces giving the blades
their general form.
According to this invention, a further step is made in this direction by replacing
the helical blades by plane blades, the position of which corresponds to that of
tangential planes to points of helical wings having the same distance from the
common axis and equal angular distances from each other.
There may be two or more blades and their outline is by preference a closed
curve, convex on the outside (circle, ellipse, etc.) and connected with the nave by
a portion of its circumference. These blades may be solid or hollow in the
centre, that is to say, annular.
Instead of complete rings, half rings may be used in certain cases, and these
half rings may be made tubular in order to increase the grip.
Maval 1908
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
I, RUDOLF COUNT WESTPHALEN, of 33A, Rennweg, Vienna III, in the Austrian
Empire, Gentleman, 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 that class of propellers, which act on the principle
of the screw, and are secured to shafts parallel to the keel of the vessel,
the said propellers acting by setting the water in motion in the direction opposite

page_text: to the direction of advance of the vessel partly by pressing on the water with
the rear faces of their blades and partly by pulling the water with the forward
faces.
The invention has for its object to join together as intimately as possible the
stream lines forming the jet or current of water, which is created in the way
referred to, so that the ris riva of the moving particles of water cannot be pre-
maturely absorbed by friction with interlying masses of still water, and that
consequently, the stream of water is enabled partly to discharge the propeller,
in a similar way to the stream of water in the suction pipe of a turbine wheel.
In order to meet this requirement, it is necessary that the stream lines should
be parallel with each other and should follow as exactly as possible helical lines
or, in other words, be arranged like the strands of a rope coiled round each
other.
As there is no reason why in the case of a plate moved within the water, other
particles of water than the next ones should follow, the direction of the stream
lines in the stream occasioned by a moving plate must always be normal to the
surface of the plate. From the foregoing statement it follows that the stream
lines in water set in motion by a plane plate must be parallel, while a helical
surface must necessarily produce divergent stream lines.
For this reason according to this invention plane propeller blades are used
and in order to give the most favourable form of cross section to the stream of
water created by the moving blades, and which are coiled round each other like
the strands of a rope, the said plane blades have a circular or elliptical outline
given to them.
In order to prevent a core of still water from being formed behind the boss
within the stream of water produced by the propeller, the blades are so constructed
and arranged that their lines of intersection with the surface of the bess extend
over nearly 180° of its circumference in the case of two blades, over nearly
120° in the case of three blades, and so on, so that, supposing the boss to be
removed and the circular or elliptical plates forming the propeller blades to be
completed, the said plates would intersect each other within the space occupied
by the boss.
The inclination of the planes of the blades against the axis of the boss varies
by preference between 300 and 40° according to whether speed or power is re-
quired. The symmetrical axes of the blades are by preference arranged perpen-
dicular to the axis of the propeller; it is obvious, however, that the effect herein-
before explained can also be obtained with an inclined position of the symmetrical
axes of the blades, as necessitated in some cases by the space available at the
stern-post.
There may be two or more blades, all having the same inclination toward
the axis of the boss in such a manner that their position may be defined as that
of tangential planes to symmetrically arranged points of imaginary helical blades,
viz., to points having the same distance from the axis of the boss and the same
angular distance from one another.
As trials have shewn that the useful effect of such propellers with plane circular
or elliptical blades is not reduced by cutting out of the centres of the blades one
tenth to one eighth of the whole area I can employ such annular blades.
In the accompanying drawing.
Figures 1 and 2 are a side elevation and top view, respectively, of a screw
propeller constructed according to the invention and having full elliptical blades
the symmetrical axes of which are perpendicular to the axis of the boss.
Figures 3 and 4 are like views of a similarly shaped propeller, the blades of
which are annular or cut away at the centre.
It will be seen by reference to Figures 1 and 2 that the plane, rigid blades b
are of elliptical shape; they may however be circular or of any other similar
shape. The planes of the blades are inclined toward the axis of the boss a at
angles of from 30° to 40°, and their symmetrical axes c are perpendicular to the

page_text: axis of the boss. As already stated, the said axes may be inclined without altering
the peculiar effect of the construction. The lines of intersection d of the faces
of the blades and the surface of the boss a extend over nearly 180° of the
circumference of the boss; consequently the completed surfaces of the two blades
would intersect each other. Owing to this construction, the water pulled by
the front surface of one blade is immediately afterwards subjected to the pushing
action of the other blade.
It is obvious that in a propeller having three blades the lines d of intersection
would extend over nearly 120° each and so on.
The propeller shown in Figures 3 and 4 has holes f formed in the centres of its
plane rigid blades b, the holes f, in the case shown extending over about one
ninth of the area of each blade. It has been found by experiment that such
holes in no way diminish the useful effect of the propeller; it seems as if the
water filling the holes serves to replace the deficiency in material.
'
For the reason explained the circular or elliptical form of the blades is most
advantageous; I can however as will be understood from the foregoing statement
employ plane rigid blades of other outline, provided that their faces embrace
180° or 120° of the circumference of the boss, as explained.
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 -
360°
1. A screw propeller for vessels the two or more rigid, plane blades of which in the
positions of symmetric tangential planes to supposed helical blades, embrace each
a portion of the circumference of the boss, which nearly equals number of blades
for the purposes of causing the stream occasioned by the propeller to consist of
parallel, closely joined stream lines, and of immediately subjecting the water
pulled by the front faces of the blades to the pushing action of the rear faces.
2. In a screw propeller of the kind referred to in the 1st Claim, circular or
elliptical blades, substantially as hereinbefore described.
3. In a screw propeller of the kind referred to in the 1st Claim, blades having
central apertures, substantially as hereinbefore described.
Dated the 1st day of December 1898.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.