Improvements in Rotary Propellers for the Propulsion of Vessels, also applicable for Producing Currents of Air for All Purposes.
Year: 1890

page_text: Date of Application, 13th Feb., 1c90
Complete Specification Left, 14th Aug., 1890-1ccepted, 11th Oct., 1890
PROVISIONAL SPECIFICATION.
Improvements in Rotary Propellers for the Propulsion of Vessels,
also applicable for Producing Currents of Air for All Purposes.
JEREMY TAYLOR MARSH of No. 1, Pembrook Road Kensington in the County of
Middlesex, Lt.-Colonel Royal Engineers, and THOMAS SEAVILLE TRUSS of No. 10,
Chesnut Villas Forest Gate in the County of Essex, Professor of Natural Philosophy,
do hereby declare the nature of our said invention to be as follows:-
These improvements consist in the construction of "rotary propellers" to effect
the propulsion of ships, and other vessels, floating on or immersed in water. The said
propellers being also applicable for producing currents of air, for all purposes.
These propellers are constructed to have a length equal to about two thirds of the
measurement of their diameters, which lengths of propellers I name," the proportion
lengths," and one end thereof, we name "the penetrant end," and the other end we
name the run."
"
the
These propellers have two or more blades, each arranged on a boss or driving shaft,
and attached thereto, at a given part thereof, in a line with the line of any angle, of
from twenty to seventy degrees, from a given point within the length of such
propellers, on the longitudinal centre line thereof, which given point we name
intersection centre," which is in distance from the "penetrant end" about one ninth
of the diameter of the propellers. The line of such angle we name the "angle for
position ;" and for every blade employed a like "line of angle for position," at equal
distances apart from each other, around such "intersection centre" is set off, and the
length of this line of "angle for position" between the "penetrant end" and "run
end" is the length for each blade. One end of such blades forms the "penetrant
end" of the propeller, and the other ends form the "run end" thereof.
The "run end" of the "line of angle for position," at the greatest diameter of
the blades, we name the "blade point of delivery." The other end of such "line of
angle for position," we name the "penetrant point of blade."
of the
Each of the blades has a peculiar curvilinear form throughout, or a part thereof
flat, and the form of each blade, on the end view of the "penetrant end
propeller, may be a vertical line from the diametrical centre thereof, or it may be
the segment of a true circle, or a decreasing curve from the commencement of the
blade near the diametrical centre, both of these two last mentioned forms, recede in
circumlation in the direction of the longest part of the "line of angle for position
from the "penetrant point of blade" and terminate at, or towards a line parallel with
the longitudinal centre line, drawn from the "blade point of delivery" to the
penetrant end" of the propeller, with their concaveness, or convexity, facing in the
same direction.
66
"
The form of line for this "penetrant end" of the blades being selected, it is
delineated on the "penetrant end" view, in the position herein before described; its
entire length being divided into short equal distances, and from these distances
straight lines are drawn to the "blade delivery point" and these lines give the form
in such "penetrant end " view, of the face for the contiguous part of the blade, to
the form of the "penetrant end" thereof, which lines we name
"the contiguous
form lines."
"
The form of each blade on the end view of the "run end" of the propeller, may be
the segment of a true circle, or a decreasing curve from the "blade point of delivery'
on such "run end" of the blade, to a point within the semidiameter, from the
"penetrant point, of the blade" on a circle thereat, set to determine the breadth of
the blades at such "run end" of the propellers. This circle is about one third of the
diameter of the propeller, and this we name the "boundary circle."

page_text: 33
Both these last mentioned forms of lines for the "run end" of such blades, recede
in circumlation in the direction of the longest part of the "line of angle for position
from the "blade point of delivery," and terminate at the boundary circle, with their
convexity facing in the same direction.
The form of line for this "run end" of the blade being selected, it is delineated on
the end view thereof, in the position herein before described, and its entire length is
divided into short equal distances, and from these distances straight lines are drawn
to the "intersection centre," and these lines give the form in such run end " view,
of the face for the contiguous part of the blade, to the form of the "
thereof, which lines we name "the contiguous form lines."
27
run end" view
When the propellers consist of two blades, each of the blades from their point of
commencement at the "penetrant end" to their ends at the "boundary circle are so
arranged that such points of each blade shall commence and terminate within the
semidiameter of the propellers, or thereabouts. And when such propellers consist of
three or more blades, each of such blades commences and terminates in a proportionate
less space, in proportion to the number of blades employed.
The side of the bla:les that press on the water or air, that enters at the "penetrant
end
of the propellers, within the area of their diameter when such propellers are
revolving, we name "the face of the blades," and the other sides thereof, I name
the
back of the blades."
"
When such propellers are applied for the propulsion of a vessel, they are situated
and rotated in the well known manner adopted for other rotary propellers.
When such propellers are applied for producing currents of air, they may be
applied for the purpose of injecting or ejecting air, and for this purpose may be
rotated in tubes, or in any other convenient chamber for such purposes.
As our said improvements are capable of various modifications without departing
from the principle thereof, I do not restrict myself to material, dimensions, or the
precise form or placement of the several parts thereof, or to the manner of attaching the
blades to the driving shaft or boss, or to the making of the blades solid with either, as
such blades may, for some purposes, be attached to the boss, or driving shaft on a
centre pin, at the intersection centre, so that the "angle of position for blade"
may be varied and fixed within certain limits, as may be desired.
Dated 13th day of February 1890.
J. T. MARSH.
THOMAS S. TRUSS.
COMPLETE SPECIFICATION.
Improvements in Rotary Propellers for the Propulsion of Vessels,
also applicable for Producing Currents of Air for All Purposes.
We JEREMY TAYLOR MARSH, of No. 1 Pembroke Road, Kensington, in the County
of Middlesex, Lieutenant Colonel Royal Engineers and THOMAS SEAVILLE TRUSS of
No. 10 Chestnut Villas, Forest Gate, in the County of Essex, Professor of Natural
Philosophy, 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 :-
These improvements consist in the construction of "rotary propellers,” to effect the
propulsion of ships and other vessels floating on, or immersed in, water; the said
propellers being also applicable for producing currents of air for all purposes.
These propellers are preferably constructed to have a length equal to about two-
thirds of the measurement of their diameters, although they may have any other
suitable proportions. One end thereof (which is in the ordinary position of the
propeller the front end) we name the "penetrant end," and the other end we name
the "run end."
These propellers have two, or more, blades, each arranged on a boss, or driving
shaft, and attached thereto at a given part of such blade.
The point where the "penetrant end" of the blade joins the boss, or driving shaft,

page_text: we call the "penetrant point of the blade," and the point of the run end of the blade
most remote from the shaft we call the "blade point of delivery."
We take a point upon the axis of the shaft, distant from the penetrant end of the
blade about one ninth of the diameter of the propeller, measured in a direction
towards the run end of the blade, and we term that the "intersection centre." To
determine the position of the blade and the "blade point of delivery," we draw a line
through the intersection centre, preferably at an angle of 30° to the axis, but this
angle may be varied if desired, between wide limits; say from 20° to 70°, though it
will usually be better to make it 30°, or thereabouts. The blade point of delivery
will be situated on this line, which we term the "angle line for position," and this
line also divides the part of the blade contiguous to the "penetrant end," from the part
contiguous to the "run end" of the blade. There is of course an angle line for position
for each blade of a propeller, the angle which the line makes with the axis being the
same for each blade, and the planes through the axis, and the several angle lines for
position, are situated at equal angular distances around the axis. A distance is set off
along this line from the "intersection centre," to give the position of the "blade
point of delivery," which is situated thereon, and the distance along that line, from
the "blade point of delivery" to the point where the line cuts the penetrant end of
the propeller, is called the length for each blade.
To obtain the form of the penetrant end of the blade we describe a curve, (which
may be a segment of a circle, or a carve in either direction whose curvature increases
as it proceeds in a direction away from the axis, or the contrary, or even a straight
line), which starts from the axis, and is in a plane perpendicular to the axis, passing
through the penetrant point of the blade. We prefer to curve such line, so that the
line drawn from the axis, in the plane aforesaid to the extremity of the curve, makes
an angle of about 20° with the tangent at the other end, i.e. so that the curve lies
between two planes through the axis inclined at an angle of about 10° to the plane
bisecting the angle between them. But this angle may be varied considerably if
desired from zero up to 60 degrees. If it be zero the penetrant end becomes a
straight line.
We have described the penetrant end of the blade as lying in a plane perpendicular
to the axis, but in practice we round the edge thereof somewhat (mainly at or near
its extremities) towards the longer part of the angle line of position, i.e. towards the
run end.
The extremity lies on; or near, a straight line parallel to the axis through the blade
point of delivery, and the line joining it to the blade point of delivery forms the
longitudinal edge of the blade.
Each of the blades has a peculiar curvilinear form (except when the penetrant end
is wholly in one plane through the axis, when part of the blade is flat). The shape of
the portion which depends on the "penetrant end" is obtained as follows:-The form
of line for this "penetrant end" of the blade being selected, its entire length is
divided into short equal distances and from these dividing points lines are drawn to
the "blade point of delivery" and these lines give the form of the part of the face of
the blade which depends on the form of the "penetrant end," which lines we name
"the contiguous form lines."
The form of the end of each blade at the "run end" of the propeller may be the
segment of a circle, or a curve of decreasing, or increasing, curvature from the "blade
point of delivery" on such "run end" of the blade to a point on a circle within the
distance from the axis of about one third of the diameter of the propeller, which we
name the "boundary circle." It lies substantially in a plane perpendicular to the
axis, but both extremities at their edges may be rounded off a little forward towards
the "penetrant end."
When the "penetrant end" is in front in line of motion the curvature of the face of
the run end of the blade has its concavity facing in the direction of the rotation of the
propeller and the "penetrant end" (if not flat) usually has its convexity turned in the
aforesaid direction. It may however be made with its concavity in the aforesaid

page_text: direction. as above explained, but in such case the concavity should be slight and this
arrangement is applicable to high speed engines.
The form of the line for the run end of the blade being selected its entire length is
divided into short equal distances and from these points lines are drawn converging to
the "intersection centre," or to a point thereabout, and these lines give the form, in
such "
run end," for this part of the face of the blade.
When the propellers consist of two blades, each of the blades, from their point of
commencement at the "penetrant end" to their ends at the boundary circle," is
so arranged that such points of each blade shall commence and terminate within a
semi-circumference of the cylinder described by the propeller, or thereabouts, and when
such propellers consist of three, or more, blades each of such blades commences and
terminates in a proportionate sector of such cylinder.
The sides of the blades that press on the water, or air, or other fluid, when it is
revolving with the "penetrant end" entering, we call the "faces of the blades" and
the other sides thereof we call the "backs of the blades." The blades may have a
uniform thickness, or the blades may have a thickness increasing from their outer
edges to, or towards, the shaft, or boss, (for additional strength). The directions
we have given are for the construction of the forms of the faces of the blades.
"
We have described the "run ends" of the blades of the propellers as terminating
on a boundary circle" but they may be continued towards the axis of the
propellers until they join each other, and we have described the "intersection
centre of the propellers as at a distance from the "penetrant end" equal to about
one ninth of the diameter of the propeller but such "intersection centre
"
"
may be
on the longitudinal centre line in line with the "penetrant end" thereof, or at
other positions thereabouts.
When such propellers are to be rotated to high velocity. then, in order to avoid
vibration, that portion of the "penetrant ends" of the blades from their "penetrant
points" on the boss, or driving shaft, to a point on the edge of each blade equal
to about th of their length longitudinally measured from such "penetrant ends
may be cut off to the line of a circle, or increasing, or decreasing, curve.
دو
By our invention rotary propellers can be constructed for the propulsion of
ships and other vessels floating on, or immersed in, water which propellers give
the greatest possible displacement of the water for their diameter and concentrate,
or direct, such displaced water, passing through, or by, them towards the axial
line of the propellers.
When propellers constructed according to our invention are applied for the
propulsion of ships and other vessels floating on, or immersed in, water they may
be situated and rotated in the well known manner adopted for other rotary pro-
pellers.
When such propellers are applied for producing currents of air they may be
used for the purpose of injecting, or ejecting, air and for this purpose may be
rotated in tubes, or in any other convenient chamber, for such purposes.
In order that the nature of our said improvements, and in what manner the same
are to be performed may be more fully understood, we will proceed to describe
the several figures on the sheet of drawing hereunto annexed, in all of which
figures like letters of reference are used to denote similar parts.
Figure 1 is a longitudinal, or side, view of a propeller constructed with two
blades A, A, attached to a boss, the said blades being formed according to our
invention. 1
Figure 2 is the "penetrant end" view, (B Figure 1), the form of line selected
for this "penetrant end" being a curve decreasing in curvature from the "penetrant
point of blade" towards the diameter of the propeller, and
Figure 3 is the "run end" view,. (C Figure 1), the form of line selected for
this run end" being a curve decreasing in curvature from the "blade point of
delivery to the circle E.
"
The dotted line a, Figure 1, is the longitudinal centre line of the propeller,

page_text: and b, is the intersection centre thereon, and the dotted lines c, c, are the "angle
lines for position" of the blades. d, d, are the "penetrant points of the blades" A, A,
and e, e, are the blade points of delivery. D, is the boss or driving shaft to which
the blades are attached. The dotted circle E, is the "boundary circle at the
"run end "of the propeller the diameter of which circle determines the breadth
of the blades at such ends. The dotted circle F, is the circumferential line
indicating the diameter of the propeller. The letters f, f, indicate the dividing
points on the lines k, k, of the penetrant end of each of the blades; and the
lines 9, 9, are the "contiguous form lines" for the face of the blades, drawn
radially from the centres e, to the points on the lines k. h, h, are the dividing
points on the lines 1, 1, for the "run ends" of each of the blades, and the lines i,
are the contiguous form lines for the face of the blades drawn radially from the
intersection point b, to the dividing points k, on the lines l.
"
The dotted line H, is the diametrical line, on either side of which the propeller
blades are situated, and the dotted line J, is a line shewing the angle of degree
from the diametrical line H, at which the blades terminate on the circle F, at the
penetrant end of the propeller."
"
The propeller should be fitted to the shaft so that the end B is next the ship,
and, when the propeller is rotated in the direction of the arrows, the ship moves
forward, whilst when it is rotated in the opposite direction the ship moves astern. It
therefore follows that if desired the propeller may be mounted in the reverse
position. We have illustrated what we consider the best form for a propeller con-
structed according to our invention, but we do not restrict ourselves to the precise
forms, or proportions, illustrated. The blades may be attached to the driving shaft,
or boss, in any suitable way; such, for instance, as by making the blades solid
therewith, or by attaching them to the boss, or driving shaft, on a centre pin at,
or about, a point coincident with the "intersection centre," so that the "angle for
position of blade
may be adjusted as desired and the blades be fixed in their
adjusted position.
"
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
22
1. A rotary propeller, for propelling ships and other vessels floating on, or
immersed in, water; and for creating air currents for all purposes, the said pro-
peller being formed with two, or more, blades attached at an angle to a boss, or
driving shaft, the form for the face of such blades, contiguous to the penetrant
end thereof, being produced by lines drawn from the "blade point of delivery'
to dividing points on the line selected for the "penetrant end thereof, and the
form for the face of the part of such blades, contiguous to the "run end" thereof,
being produced by lines drawn from the "intersection centre" to dividing points
on the line selected for the "run end" of such blades; substantially as herein-
before described.
2. The construction of a propeller as hereinbefore described and illustrated in
the accompanying drawings.
Dated this 19th dow of An 1800
JEREMY TAYLOR MARSH, Lieut.-Col. R.E.
THOMAS SEAVILLE TRUSS.