Year: 1887

page_text: Date of Application, 11th Jan., 1887.
Specification Accepted, 29th Mar., 1887.
I ALEXANDER VOGELSANG, of New York, in the United States of America,
Manufacturer 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 :-
My invention relates to screw propellers, and has for its object the construction of a
single screw propeller in which the blades are arranged in pairs, and each blade
different from the one immediately preceding or following it. The blades may be
arranged in pairs diametrically opposite to each other, or they may be grouped in
pairs in either construction the leading and trailing edges of the adjacent blades
are the reverse the one of the other.
Under the present construction of single screw propellers the blades are each made
the counterpart, one of the other, that is to say, a certain fraction of a turn of a screw
is used for all blades alike and the blades have all the same angle of inclination and
the same pitch, the consequence is, that in the rapid revolution of the propeller the
water is churned to such an extent that it produces a vacuum at the rear of the hub
and a drag upon the vessel, and the displacement of the water by the blades of the
propeller absorbs a large percentum of the power of the engine which should be
utilized in giving additional speed to the vessel. By my construction of a propeller
the churning of the water is not only reduced to the minimum but the body the water
is rendered more compact than by any other known construction, and the power
developed by the engine is applied directly to accelerate the speed of the vessel.
In order to enable my invention to be fully understood 1 will proceed to describe
the same by reference to the accompanying drawings in which figure 1 represents a
diagrammatic view of a screw with the blades indicated in dotted lines, preparatory to
cutting them out to form a pattern for moulding my screw propeller. Figure 2
represents an end view of a propeller constructed according to my invention.
Figure 3 is an elevation or side view shewing the tips of the blades on different planes.
Figures 4 and 5 are respectively end and side views of a propeller in which the tips of
the blades are on the saine plane, in the latter figure the view is taken in the direction
of the arrow 1 in figure 4. Figures 6 and 7 are respectively end and side views of a

page_text: modified construction of a propeller. Figures 8 and 9 are respectively similar views
of another modification and figures 10, 11 and 12 are diagrammatic views.
The leading features of construction in my propeller are, that instead of a like
fraction of a turn of a screw being taken for all of the blades, two blades diametrically
opposite to each other are fractions of a like part of a turn of a screw and the other
two blades diametrically opposite to each other are like fractions of another part of the
same turn of a screw, as shewn in figure 1. That each blade is the reverse of the one
immediately preceding or following it, that is to say, that the cutting edge of one
blade conforms to the configuration of the trailing edge, and the trailing edge of the
one to the cutting edge of the other blade. That all of the blades have substantially
the same twist or turn of a screw thread but are cut off the reverse the one to the
other, as shewn in figure 1. That the angle or curve of the face of the blades is such
that in entering the water one blade displaces it toward the hub while the next blade
following it displaces the water away from the hub. That each blade presents the
same working surface to the water or that the faces of all the blades are substantially
alike while the cutting and trailing edges are reversed in each alternate blade.
Having set forth the general features of construction I will now proceed to describe
them in detail.
Reference being had to the drawings and the letters marked thereon A, represents
the hub, from which radiates a series of blades B, which are disposed equidistant
around the hub in pairs arranged diametrically opposite to each other as shewn at 2, 3
and 4, 5 in figures 1, 2, 3, 4 and 5 or they may be grouped in pairs as shewn at 6, 7
and 8, 9, in figures 6 and 7 and 10. 11 and 12, 13, in figures 8 and 9. In either
construction it will be observed that the blades which are diametrically opposite to
each other on the hub, have their cutting or entering and their trailing or leaving
edges made to conform the one to the other.
In the several figures, a, represents the cutting or entering edge of the blades
and, the trailing or leaving edge. The contour of one of these edges may be a
right line or a curve as shewn at c, in figures 6 and 8 or it may be a right line and a
curve combined as shewn at d, in the same figures. The opposite edge of each blade
may be in the form of an ogee or cyma as shewn at e, in the several figures or it may
be a true curve. In these several figures it will be observed that the concave line
begins near the hub and merges into the convex line which in turn merges into the
periphery of the blade.
By referring to figures 2 and 4, it will be observed that the curve of the blades by
which the water is displaced toward and away from the hub is indicated by shade
lines, and arrows upon the faces of the several blades in figure 4 shew the direction of
displacement of the water produced by the revolution of the wheel. By this
construction of the blades, centrifugal motion imparted to the water by one blade is
arrested and counteracted by the next blade following it, a churning motion of the
water and the formation of a vacuum in the trail of the wheel prevented, while
the water is kept as near a state of rest as possible, thus affording increased resistance
to the revolving propeller and the tendency of one blade to give lateral motion to the
vessel is counteracted by the next succeeding blade. By the effect upon the water
described the drag on the vessel is reduced to the minimum, and the speed greatly
accelerated.
The pitch of the blades may be uniform from the hub to the periphery or ends of
the blades, or it may be of an expanding or a variable pitch; or the blade may be flat
and set at a suitable angle to the shaft.
The tips of the blades may be disposed of in the same plane, as shewn in figure 5, or
they may be disposed in different planes as shown in figures 3, 7 and 9; but in every
instance the plane of the blades at their point of juncture with the hub should be such
as to permit a single plane that is perpendicular to the axis of the propeller to cut
through them all as shewn by the lines of vision x, y in the diagrammatic view given
in figure 11 and also by line z, in figure 12. By reference to these figures 11 and 12
it will be observed that the blade nearest the point of vision always partly obstructs the
one beyond.

page_text: While the blades may be thus variously disposed upon the hub, they must in no
instance be so placed as to have one blade in front of another in the line of the
propeller shaft, or in other words, the beneficial results due to the construction of the
blades will not be developed in a double or twin propeller for the reason that the rear
blades would move directly across the path of the water displaced by the forward
blade and thereby obstruct the passage of the propeller through the water and retard
the speed of the vessel correspondingly.
Instead of forming the blades integral with the hub, as shewn, they may be made
separate therefrom and be attached to the hub in any well known manner.
By my improved construction and arrangement of the blades a material increase of
speed is obtained with a smaller expenditure of power as compared with the propellers
now in use, while it improves the steering and turning qualities of a vessel and enables
a vessel to be run backward without the tendency to work off to one side, which in
ordinary propellers requires the use of a helm to counteract this action of the propeller
and to keep the vessel in line.
I do not limit the application of my improved screw propeller to the propulsion of
vessels in water, as it may be applied to aerial ships, to tubes for raising water, and
other useful purposes.
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 :-
1. A single propeller having blades disposed around a hub in pairs, one pair of the
blades arranged diametrically opposite to each other on the hub being like fractions of
a turn of a screw and the other pair also diametrically opposite to each other being
like fractions of another part of the same turn of a screw.
2. A single propeller provided with a series of blades, the working faces of all of
which are substantially alike, and whose cutting and trailing odges are reversed one to
the other, substantially as described.
3. A single propeller provided with a series of blades whose cutting and trailing edges
are reversed one to the other, and one blade constructed to displace water toward the
hub and the adjacent blades constructed to displace water away from the hub,
substantially as shewn and described.
4. A single propeller provided with a series of blades, having approximately the same
twist, disposed around a hub, and arranged in pairs, the cutting and trailing edges of
one blade of each pair being reversed to the cutting and trailing edges of the adjacent
blades, substantially as described.
5. A single propeller provided with a series of blades whose cutting and trailing
edges are reversed one to the other, and disposed upon approximately the same plane
at their point of juncture with the hub, and at different planes at the tips or ends of
the blades, substantially as described.
6. A single propeller provided with a series of blades whose cutting and trailing
edges are reversed one to the other and disposed around a hub in such relation thereto
that a single plane that is perpendicular to the axis of the propeller will cut through
all of the blades substantially as described.
7. A single propeller having a series of blades, one edge of which is formed of straight,
curved, or straight and curved lines, and the other edge in the form of a curved line,
an ogee or cyma, the cutting and trailing edges being reversed on each alternate
blade, substantially as described.
Date the 10th day of January 1887
G. F. REDFERN,
4, South Street, Finsbury, London,
Agent for the Applicant.