Improvements in Propellers.
Year: 1898

page_text: Date of Application, 20th Dec., 1898-Accepted, 11th Feb., 1899
Improvements in Propellers.
I, WILLARD REED GREEN, residing at No. 1325, Gilpin Street, in the City of
Denver, in the County of Arapahoe, and the State of Colorado, United States
of America, Engineer, 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 propellers for the propulsion of vessels, and which
may be used for other purposes, such, for instance, as moving air.
The object of my invention is to more effectually utilize the driving power
applied to the propeller.
My improvements consist of providing an improved form and arrangement of
the vanes composing such propeller and which act more effectively upon the
water actually engaged thereby and with less disturbance of the surrounding
portions of water.
Referring to the drawings, Fig. 1 shows an elevation of one embodiment of
my invention, the view presented being a projection of an outline of the same
taken across or through the widest diameter or lateral extension of the vanes
relatively to the axis thereof.
Fig. 2 is a perspective view of an embodiment of my said invention taken
diagonally from the rear toward the front, showing the rear of the boss and
indicating some of the curvature of the vanes.
Fig. 3 is a transverse section on the line ar, Fig. 1, looking toward the rear,
R being the axis of rotation.
Fig. 4 is a view similar to that shown in Fig. 2, and intended to indicate by
shading more fully the lines of curvature of that embodiment of the invention.
Fig. 5 is a view of an embodiment of the invention when viewed laterally
across the vanes and at an acute angle directed forward to the axis.
Fig. 6 is a similar view from a point more nearly at right angles to said axis.
Fig. 7 is a view at right angles to the flat sides of the vanes intended to
indicate the curvature of some portions thereof.
It should be borne in mind that the views presented of a given proveller will
vary greatly with the point of view from which they are taken and that the
lines of curvature are necessarily somewhat altered with the size and purpose
and working conditions of the propeller, and hence that to correctly represent a
given propeller, the conditions stated must be known.
In the drawings, 4 represents the boss of the propeller, to which are fixed the
vanes 2 and 3, which may be made integral with said boss or may be attached
thereto as desired. Said vanes are fixed to said boss by the inner edge of their
forrard portions and are so attached throughout approximately one-half their
longitudinal extension and opposite the portion of their greatest width. Said
vanes are attached to said boss at an inclination with the axis thereof equal to
approximately the diameter of said boss that is to say, the leading or forward
edge of said vane ioins the forward end of said boss at a point practically at
|right angles with the plane of the flat portion of said vane, and said line of

page_text: juncture follows said boss around the circumference thereof to a point on the
circumference of said boss at its rear end in the plane of said flat portion of
the vane and practically at the opposite side or diameter from the point of
beginning, thus completing practically one-half a revolution around said boss
which is equal to the diameter of same and forming a corresponding curve
therewith. This line of juncture and the resulting curvature will depend upon
and be varied with the purposes, working conditions, and size of the propeller,
but the form indicated best embodies the invention and is a preferable form.
Thus a vane is provided having its main working or propulsion surface 11
substantially in the plane of the axis or at a small angle thereto, as shewn at
11 in Fig. 5 and having its forward or entering end or section 12 curved in
the direction of rotation.
To the rearward of the boss 4 of said propeller the vanes 2 and 3 continue as
substantially flat projections 10, but may be thickened or reinforced, if desired,
upon the backs thereof to suit conditions. It will be observed that owing to the
manner in which said vanes leave the rear extremity of the boss that they lie in
planes practically parallel and separated from each other by a distance equal to
practically the diameter of the boss and may be more or less to suit conditions.
Said vanes continue in their rearward projections in practically said planes, the
degree of inclination of which to each other may be nothing, that is to say they
may be parallel, or they may be separated as desired, and may also be at unequal
angles with the axis of the propeller.
The said vanes may at the rear of the boss overlap, as shown in Figs. 12
and 3, whereby said vanes will appear as super-imposing, as indicated in Fig. 3,
and the degree of this lap, or overhang, as well as the manner of leaving the boss
may vary as desired, its purpose being hereinafter explained.
Immediately after leaving the rearward end of the boss, the inner edges of the
vanes are cut away or concaved, as indicated at 7, and this may be to a degree
and for a longitudinal distance desired, depending upon working conditions.
To the rearward of the point 8, in Fig. 1, or the rearward extremity of the
concave portion, said vanes taper to their ends, as indicated at 9 in Fig. 1. The
degree and variation of this reduction of width will vary with given conditions
and for different purposes, and may be of unequal or varying degree in the two
vanes with the result that said vanes will have different forms and width and will
stand laterally at different distances from the axis of the propeller, both as to the
distance of their planes from said axis (compare the distances cand e Fig. 3)
and the distance at which their inner edges 1 stand with a line or plane drawn
at right angles through said axis and through their said planes (compare their
distance apart from the axial line w Fig. 1) and said vanes may be of unequal
length.
The object of this arrangement is that the said rearward portions of the vanes
may not travel in exactly the same path around the axis of rotation, but may have
different paths and may to some extent intersect and act upon different water and
also counteract currents and any vortex formed by each in its revolution.
It will thus be seen that while the two vanes 2 and 3 are not exactly alike in
their contour outlines, they are generally similar. It will also appear that the
curvature of the forward portion of the vanes out of the plane of the main working
surface of said vane in the direction of rotation and toward the axis of rotation may
vary, and the degree and nature of this curvature will vary with the conditions of
working, the size of the vessel to which it is applied and the desired speed.
It will thus be seen that a vane is provided, the greatest length of which
extends longitudinally with the line of progression of the propeller, and also lies
mostly in a plane substantially parallel with the axis of rotation of the propeller
or at a small angle thereto.
It will also appear that a vane is provided consisting of sections different in
their formation, their functions and their objects, and the actions of which
constitute a series of effects resulting in a rearward impulsion of the water.

page_text: Also, a propeller is provided the largest diameter of which is toward the
forward or entering end, and of which the diameter diminishes towards the rear
end.
The purposes of the form and disposal of the different portions of the vane are
as follows:
The middle portion or section of the vane is intended to be the main working
or propulsion surface. It is not adapted by its form to enter and cut off the
water, but to act upon the same after it has been engaged by the forward section,
and it is seen that this surface lies in a plane more or less in the line of pro-
gression, and consequently in its rotation will act upon the water at an angle
more or less a right angle to the axis, or the line of progress, and will impact
said water at a relative angle, the resultant of its progress and its rotation.
The forward section or entering end of the vane is intended by its curvature
to cut off or engage the water to be acted upon in the advance of the propeller and
said curve is given a pitch or curvature adapted to so enter and intersect and cut
off said water and to throw said water to the rearward and upon and into the
pathway of the following propulsion surface, and, as stated, the said curvature
will have a relation to the depth at which the propeller is working, the immersed
section of the vessel, the desired speed and the power to be applied.
The object of the rearward continuation or section of the vane is to continue
the propulsion effect, to prevent the formation of a vortex at the end of the
boss, to provide an open clearance or frec-way for the waters in the central
portion of the propeller and to gradually smooth down and release the waters
acted upon.
The object of the separation of the planes of the vanes in their rearward con-
tinuations and the concaved portions mentioned is to provide free-way by which
water passing directly along the axis may find ready outlet with a minimum of
revolution.
The actions and functions of the different parts or sections of the vanes are
as follows:
Upon the rotation of the propeller, the forward or entering curved section of
the vane enters the water upon which the propeller is advancing and engages or
cuts off the water for a given rotation or stroke of the vane. The water thus cut
off by the curved or entering section is by the curvature of said section projected
rearward upon and into the pathway of the main working or middle section of the
vane and which is then advancing upon said water with a direction of impact
and pressure, the resultant of its forward progress in a line parallel with the axis
and its rotation at a right angle thereto, and which, all things being equal, will
cause said vane to engage said water at an angle of approximately 45 degrees,
depending upon the speed of the vessel and the rate of rotation, and which will
result in the rearward propulsion of said water.
The curved line of diminishing radius of the vane being such that the most of
the water after offering its greatest resistance to the impact of the vane is allowed
to escape to the rearward immediately back of the widest part of the vane or the
greatest diameter of the propeller, the operation of the propeller is freed from
secondary or interfering effects from the greater portion of the water acted upon.
The water occupying and engaged by the middle longitudinal zone of the
propeller though acted upon by the leverage of a shorter radius is under its
influence longer in its longer longitudinal travel with the vanes' continuations
and with corresponding advantage.
The remaining portion of the water or that from the central portion of the
propeller, and which is ordinarily disposed to form a vortex at the tail of the axis,
is given a vent by the separation of the planes of the vanes at the rear of the boss
and by the concaving of the inner edges of the vanes, and the free-way offered
thereby to the passage of water from the central portions of the propeller is kept
open by the action of the flat continuations of the vanes, which continuations
owing to said separation of planes act upon said water obliquely, intersecting

page_text: it with their edges and with their flat sides forming a tubular outlet or passage,
preventing the influences tending to form a vortex, the tapering blades or rear
ends of the vanes offering a gradually diminishing influence of the propeller upon
the water and gradually permitting it to come to rest.
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 propeller consisting of a central boss 4, serving as the axis of said
propeller and having vanes of greater longitudinal dimension than the length of
said boss, placed thereon and fixed thereto by the inner edges of the forward
portion only of said longitudinal dimensions, and the rearward extension of which
vanes is in lines practically parallel with the axis of said propeller.
2. A propeller consisting of a central boss or axis 4, and vanes of greater
length than the radius of said propeller, placed thereon and fixed to said boss upon
the inner edges of their longest dimension, and the rearward extension of which
vanes is in lines practically parallel with the axis of said propeller.
3. A propeller consisting of a central boss or axis 4, and vanes of greater
length than the radius of said propeller, placed thereon and fixed to said boss upon
the inner edges of their longest dimension, the said vanes diminishing in width
upon their outer edges in their rearward continuation, whereby a propeller is
formed the greatest diameter of which is at its forward or entering end and of
which the diameter diminishes towards its rear.
4. A propeller consisting of a central boss or axis 4, and vanes of greater
length than the radius of said propeller, placed thereon and fixed to said boss upon
the inner edges of their longest dimension, the said vanes diminishing in width
upon their outer edges in their rearward continuation, and the outer edges of said
vanes forming a contour of diminishing radius of said propeller, whereby the
water engaged is acted upon for a time inversely proportioned to the radius
engaging said water.
5. A propeller consisting of a central boss or axis 4. and vanes of greater
length than the radius of said propeller, placed thereon and fixed to said boss upon
the inner edges of their longest dimension, the said vanes diminishing in width
upon their outer edges in their rearward continuation, and the outer edges of
which vanes form a contour curve of diminishing radius of said propeller, whereby
the area of the working surfaces of said propeller is in proportion to the radius
and the impact thereof upon the water engaged.
6. A propeller consisting of a central boss 4, serving as the axis of said pro-
peller and having vanes 2 and 3. of greater longitudinal dimension in line parallel
with the boss than the length of said boss, placed upon said boss and fixed thereto
upon the inner edges of the forward portion only of said longitudinal dimension
and the rearward continuations of which vanes 'beyond the rear of said boss lie in
planes substantially parallel with and clear of the axis of said propeller, whereby
free-way is provided through the central portion of said propeller.
7. A propeller having a central boss 4 constituting the axis of said propeller
and vanes 2 and 3 fixed thereon, the greatest length of which propeller lies in
planes practically parallel to its axis of rotation and whose greatest curvature is
at the forward or entering end of said vanes.
8. A propeller having a boss 4 constituting the axis thereof and vanes 2 and 3
fixed to said boss throughout approximately the forward half of their inner
edges only and the greatest length or extension of which vanes is rearward and of
which the pitch or curvature diminishes as they extend rearward, and gradually
merges into and continues in planes parallel with the axis of rotation.
9. A propeller having a boss 4 and vanes 2 and 3 fixed thereon and continu-
ino bevond the rear of said boss in substantially parallel planes upon opposite
sides of the rear of said boss and the inner edges 7, 8 of which continuations
overlap and are not of equal distance from the axis of said propeller, whereby

page_text: said rearward continuations of said vanes do not travel in the same path of
revolution around the axis.
10. A propeller consisting of a boss 4 and vanes 2 and 3 fixed thereon, said
vanes being substantially longitudinal and of diminishing curvature as they
progress rearward, and merging into parallel planes passing the rear of said boss
on opposite sides thereof, and lying at different distances from the axis of said
propeller, and whose inner edges 7, 8 partially superimpose or lap.
11. A propeller consisting of a boss 4 and vanes 2 and 3 fixed thereto, which
vanes 2 and 3 have flat continuations or sections 10 extending beyond the boss of
said propeller and lying in substantially parallel planes on opposite sides of said
boss and which continuations 10 diminish in width in their rearward progression
by substantially similar contour lines of diminution, but not exactly equal in
degree, whereby the inner edges 7 and 8 of said sections 10 may stand at different
distances from a plane intersecting the axis of said propeller at right angles to said
vanes and portions of said edges may lie upon opposite sides of said intersecting
plane, and whereby said sections 10 will not travel in the same path around the
axis of revolution of said propeller.
12. A propeller consisting of the boss 4 and vanes 2 and 3 thereon, said vanes
being divided into entering, middle, and rearward sections or planes 12, 11, and 10,
of diminishing curvature and diminishing width upon their outer edges in their
rearward progression, whereby said vanes act as continuous propulsion surfaces
while performing different functions upon the water acted upon by different
portions of their length and the least disturbance is produced upon said water
and its greatest movement is rearward.
13. The herein-described propeller, consisting of the boss 4 and the vanes 2
and 3 mounted thereon, the entering, middle, and rearward sections 12, 11, and 10
composing said vanes, the lines of curvature determining the same upon their
outer and inner edges, all related and coacting substantially as described.
14. In a propeller, a vane whose greatest length is longitudinal in a line
parallel to the axis of rotation of said propeller and longer than the boss of said
propeller and is joined to said boss upon the inner edge of its forward portion
only, and the rearward continuation of which vane extends beyond the rear of
said boss substantially in a plane with the circumference of said boss at the point
of passing beyond the same.
15. In a propeller, a vane whose greatest length is longitudinal in a line
parallel to the axis of rotation of said propeller and longer than the boss of said
propeller and is joined to said boss upon the inner edge of its forward portion
only, and the line of juncture of which vane with said boss forms a varying curve
around the circumference of said boss from the front to the rear thereof equal to
approximately one-half a turn around said boss and the degree of which curve in
its rearward progression is determined by the intended speed and working
conditions of said propeller.
16. In a propeller, a vane of which the greatest dimension is longitudinal in a
line parallel with the axis of the propeller and of which the greatest width is
toward the forward end and which is joined to the boss of said propeller along the
inner edge of the forward portion of said vane and opposite to and at right angles
with the line of its greatest width.
17. In a propeller, a vane, the greatest dimension of which is longitudinal in a
a line parallel with the axis of said propeller, said vane having its greatest width
toward the forward or entering end thereof and diminishing toward its rearward
end, the reduction in the width of said vane being made in the outer edge thereof
beyond the radius of the boss of said propeller.
18. In a propeller, a vane of which the greatest dimension is its length
longitudinal in a line parallel with the axis of said propeller, and the greatest
portion, of which length lies in a plane more or less parallel with the axis of
rotation.
19. In a propeller, a vane of greater longitudinal dimension than the boss of

page_text: said propeller, joined to said boss of said propeller along the inner edge of its
forward end and the rearward portion of the edge of which vane passes beyond the
boss of said propeller in its rearward continuation at a point on the circumference
of said boss approximately 180 degrees from the point of juncture of the forward
portion of said vane with said boss, following a line of varying curvature in its
travel around the circumference of said boss, the degree of curvature of which line
is greater toward the forward end of said propeller.
20. In a propeller, a vane of which the greatest dimension is longitudinal in
a line parallel with the axis of said propeller and substantially along the line of
juncture of said vane with the boss of said propeller and the length of which
propeller decreases as the radius thereof increases.
21. In a propeller, a vane the greatest extent of which is longitudinal in a
line parallel with the axis of said propeller, and the length of which vane is
divided into entering, middle and rearward sections or planes of varying curva-
ture, and of which the middle section 11 of the largest area, consists of a plane
lying approximately parallel with the axis of said propeller, and constitutes the
main working or propulsion surface of said propeller; the forward section 12
consists of a plane curved in the direction of rotation of said propeller and consti-
tutes the entering edge or surface of said propeller; and the rearward section 10
consists of a flat plane lying substantially parallel to the axis of rotation and
constitutes the smoothing and quieting section of said vane, the said sections
merging each into the other and coacting, whereby the forward or entering
section 12 cuts off and engages the water to be acted upon and projects the same
rearward upon and into position to receive the impact of the middle section 11,
which engages the same with a resultant pressure in a rearward direction where it
is laterally engage by the section 10 and given an increased longitudinal speed
by the longer extension of said section 10 in proportion to its diminishing radius.
22. In a propeller, a vane having greater length than the boss of said propeller
to which it is joined upon the inner edge of its forward portion and throughout
the length of said boss, said vane having a greatest width equal to approximately
one-half its length and diminishing toward the rear of said vane, the larger por-
tion of the surface of said vane lying in a plane substantially parallel with the
axis of said propeller, and constituting the main working or propulsion surface
of said vane, said vane bearing upon its forward portion an entering section
curved in the direction of rotation adapted to enter and cut off the water upon
which said propeller is advancing, whereby said middle or main working surface
is enabled to engage and act upon the water through which said propeller is
progressing.
23. In a propeller, a vane extending rearward beyond the rear of the boss of
said propeller in a plane parallel with the circumference of said boss, the inner
edge of which vane extends beyond a line at right angles with said vane and the
axis of said propeller and which vane upon its said inner edge is concaved or cut
away for a portion of said vane immediately adjoining the rear of said boss,
whereby the free-way through said propeller and along the circumference of said
boss is increased and the said vane at the place so concaved co-operates with
an opposite vane in the said propeller to counteract and prevent the formation
of a vortex.