Improvements in Screw Popellers.
Year: 1889

page_text: Date of Application, 20th Mar., 1889
Complete Specification Left. 20th Dec., 1889-Accepted, 25th Jan., 1890
PROVISIONAL SPECIFICATION.
Improvements in Screw Popellers.
I EDOUARD EMMANUEL DE FACIEU, of Elephant Point (near) Rangoon, India,
Clerk Eastern Extension Australasin and China Telegraph Company Limited, do
hereby declare the nature of this invention to be as follows:-
The object of my invention is to provide means whereby the water is prevented
from escaping laterally under the tangential force imparted to it by the rotation of
the propeller and to compel all the water that has been acted on by the blade to
escape in a direction parallel to the shaft whereby the tangential or centrifugal force
is to a great extent neutralized, and "short circuiting" of the blade is prevented.
My invention consists in providing the blades of the propeller with a terminal
flange at right angles to the terminal plane of the blade and this flange is approxi-
mately semi-circular or semi-elliptical in shape. The outer edges of the blades where
they bend at an angle to form the flanges are not square or concentric with the
shaft, the leading edge is raised and the following edge correspondingly depressed in
such a way that the rotation of the propeller describes a section of an elongated cone,
the apex of which is on the line of the shatt or axis of rotation at a certain distance
behind the vessel thereby counteracting centrifugal force by driving the water in a
direction not strictly parallel to the shaft but slightly inclined towards it. The angle
thus formed by the plane of the flange with the central axis should in all cases be
small or else whatever advantage is gained by this mode of construction may be lost
through increased frictional resistance, the angle may however be greater in gun-
metal propellers than in cast iron propellers owing to the greater smoothness of surface
obtainable with the former metal.
I am aware that many attempts have been made with the view of counteracting
centrifugal force for example spiral curves have been given to the blades, and rihs
have likewise been provided to screw blades but the shapes, positions and directions
of such have not been effective or similar, nor have they produced the same results
that I obtain by my invention; also in other cases the blades have been depressed
to an angle with the shaft in its axial direction but although such form of propellers
will and do give an increased efficiency when going ahead they give correspondingly
decreased pull when going astern whereas propellers constructed according to my
invention are far more effective than any ordinary model when going ahead while
equally effective with them when the engines are reversed. Owing to its construction
it takes up very little more space than those in ordinary use as the greater part of
the flange or flanges lies in the plane of rotation.
11
كيمى
1 1000
COMPLETE SPECIFICATION.
Improvements in Sorew Popellers.
I, EDOUARD EMMANUEL DE FACIEU of Elephant Point (near) Rangoon, India,
Clerk Eastern Extension Australasia and China Telegraph Company Limited, 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:-
The object of my invention is to provide means whereby the water is prevented
from escaping laterally under the tangential force imparted to it by the rotation of

page_text: the propeller and to compel all the water that has been acted on by the blade to
escupe in a direction parallel to the shaft, the tangential or centrifugal force being
to a great extent neutralized and "short circuiting" of the blado prevented.
My invention will be clearly understood by the following description referring
to the accompanying drawings, in which latter is illustrated at Figure 1 an end
elevation of a screw propeller constructed according to my said invention, Figure 2
is a side elevation of same, and Figure 3 shews a general view in side elevation of
such a screw propeller drawn to a somewhat smaller scale; Figure 4 is a plan view
of the propeller shewn at Figure 2, and Figure 5 is a plan of a slightly modified
form or arrangement of my invention. Figure 6 is a diagram view hereafter
mentioned.
According to my invention I provide or form the blades A A of the propeller with
terminal flanges B extending at right angles to the terminal planes of the blades and
these flanges are approximately semi-circular in shape as in the plan view Figure 4,
or they may be semi-elliptical in shape as shewn at Figure 5. The object of these
flanges is to prevent the water from escaping laterally under the tangential force
imparted to it by the rotation of the propeller and to compel all the water that has
been acted upon by the blade to escape in a direction parallel to the shaft. Thus the
tangential or centrifugal force is to a great degree neutralized. and "short-circuiting"
of the blade is prevented, the tip of the blade (which is in this propeller its broadest
part) becomes also its most effective part.
The propeller shewn at Figures 1 and 2 is formed with two blados, but. I do not
limit myself as to the numbor of the blades, nor as to the formation or pitch of the
screw, nor does the mode or material of its construction come within the scope of
this my present invention for the propeller may be cast in one piece or the blades
may be bolted on to the boss or hub. all according to circumstances.
The outer edges of the blades A where they bend at an angle to form the flanges B
are not square or concentric with the shaft as is clearly shown at Figure 2 but the
leading edge is raised, and the following edge d correspondingly depressed in
such a way that the rotation of the propeller causes the flange to describe a section
of an elongated cone, the apex of which is on the line of the shaft or axis of rotation
at a certain distance behind the vessel, thereby still further counteracting centrifugal
force by driving the water in a direction not strictly parallel to the axis of the
shaft but slightly inclined towards the axis. The angle thus formed by the plane of
the flange B with the central axis C should in all cases be small, or else whatever
advantage is gained by this mode of construction may be lost through increased
frictional resistance; this angle may however be greater in gun-metal propellers
than in cast iron propellers owing to the greater smoothness of surface obtainable
with the former metal.
It should be remarked that in action the flange B when constructed according to
my invention moves edgewise through the water in the direction and as shewn by
the diagram Figure 6, this being the position which offers the least resistance to its
movement and also the said flange B extends or projects well to the rear as is
shewn at Figures 4 and 5, the position and shape of the said flange being thus
essentially suited to effect its object, that is, to confine and deflect the water as
far as practicable even after it has been acted upon by the blade, and to so compel
it to escape in an axial direction.
1 am aware that many attempts have been made with the view of counteracting
centrifugal force, for example spiral curves have been given to the blades, or the
blades have been depressed to an angle with the shaft in its axial direction, but
although such forms of propellers will, and do, give an increased efficiency when
going ahead, they give correspondingly decreased pull when going astern,
whereas propellers constructed according to my invention are far more effective than
any ordinary model when going ahead, while equally effective with them when the
engines are reversed. Owing to its construction it takes up very little more space
than those in ordinary use, as the greater part of the flange or flanges lies in the
plane of rotation. I am also aware that rihs have been provided to screw blades,

page_text: but the shapes, positions, and directions of such have not been arranged with the
same object, nor have they been as effective or produced the same results that I
obtain by my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First In screw propellers, the flange B situated at the extremity of each blade of
the propeller, in such manner that the plane of each flange is concentric with the
axis of rotation substantially as set forth.
Second: In screw propellers, the flange B, situated at the extremity of each blade
of the propeller and formed in such manner that the plane of each flange is con-
centric with the axis of rotation as at Figure 6 and also extends or projects towards
the rear of the blade beyond the plane of the said propeller as at Figures 4 and 5 and
is narrowest at its leading edge & substantially as set forth.
Third: In screw propellers, the flange B situated at the extremity of each blade of
the propeller the plane of said flange being concentric with the axis of rotation as at
Figure 6 and so formed that the leading or narrow edge of the said flange B is raised
above its broad or following edge as at Figures 1 and 2 and so forms an angle with
the axis of rotation all substantially as set forth.
:
Fourth In screw propellers the flange B situated at the extremity of each blade
of the propeller, and formed in such manner that the plane of each flange is concentric
with the axis of rotation as at Figure 6 extending or projecting towards the rear of
the blade and being narrowest at its leading edge as at Figures 4 and 5, the said
narrow or leading edge being also raised above its broad or following edge as at
Figures 1 and 2 and forming an angle with the axis of rotation all substantially as and
for the purposes herein described and illustrated with reference to the accompanying
drawings.
Dated bus way
ED. E. DE FACIEU.
By Brewer & Son,
33, Chancery Lane, London, Patent Agents.