Ascertaining by means ola полет THE DUBL Number and Form to be Given to the Blades (or Fans) of the Propellers of Navigable Balloons and of Ships.
Year: 1885

page_text: AL REVENTION 10 Ascertaining by means ola полет THE DUBL
Number and Form to be Given to the Blades (or Fans) of
the Propellers of Navigable Balloons and of Ships.
I WILLIAM NELSON HUTCHINSON of Wellesbourne, Bideford, in the County of
Devon General in Her Majesty's Army, do hereby declare the nature of my
Invention for ASCERTAINING, BY MEANS OF A MODEL, THE BEST NUMBER AND FORM
TO BE GIVEN TO THE BLADES (OR FANS) OF BALLOON PROPELLERS AND OF SHIPS
to be as follows:-
Great doubt exists as to the best number of blades (fans) that should be attached
to the shafts of the propellers of navigable balloons-also as to their size, shape
and curve also at what exact angle their faces should incline from the axis of the
shaft. This perplexing question exists whatever be the nature of the power by
which it is driven.
Much light would be thrown upon this subject-which is becoming one of
increasing importance as the science of aeronautics advances-by making experi-
ments with inexpensive models thus constructed.
To act the part of the shafts of the propellers I have two similar steel cylinders,
say, nearly 6 inches long and half an inch in diameter, similarly grooved (cogged)
in their whole length. Thin steel axes, say, 5 inches long, project from both ends
of each cylinder (shaft) and rotate in circular holes at the head of similar uprights,
say, 8 inches high fixed about a foot apart. Both cylinders with their respective
pair of uprights are so fixed on a board that they are parallel to each other in
their length. The uprights also are parallel in a transverse direction. The
cylinders can move freely horizontally when actuated by the blades (fans) here-
after described. Rotation is given to those cylinders by a large driving wheel
which plays the part of the steam or other driving. power. It is, say, a dozen
times the diameter of the cylinders. Its periphery is similarly steel-cogged. It
stands midway between the cylinders and is in contact with both at right angles
to their axes. Its axis revolves in circular holes in two uprights attached to the
board. The operator gives revolution to the wheel by means of a crank-handle.
The revolution of the cylinders must evidently be alike whatever may be the rate
at which the driving wheel is turned. The part of blades is performed by cuttings
made on sheets of tin, or black iron, called in the trade, lateen. The substance of
the sheets selected, depends upon the size of the model. No more thickness is
required than will prevent the blades, when revolving with the greatest rapidity,
from yielding to the pressure of the wind. With the same radius I draw many
circles on similar sheets, and, parallel to the direction of the radii, cut differently

page_text: rigid nearly complete sections to act as the blades or fans. No two circles are
similarly cut. I leave uncut a circle nearly an inch in diameter around the centre,
with a central hole to receive the axis of one end of a cylinder. All the blades cut
on one circle are alike, but the blades of no two circles are alike. By clipping
I reduce the sectional pieces to any size or number I consider desirable, and by
manual or other pressure easily give them any curve. Opposite the axis that does
not carry the set of blades; there is a spiral spring so arranged that when that axis
is forced against it by the action of the Blades it yields to the pressure. The
extent to which it yields is the measure of the excellence of its set of blades, and
is marked by the spot to which a wire indicator retires within its sheaf, fixed
horizontally in the line of the axis. To test the value of the forms &c given to
the blades, I take two sets, slip one on an axis of each cylinder-fasten them
temporarily with a screw or two, and operate upon the, driving wheel. I after-
wards quickly remove whichever set least succeeds in forcing home the indicator,
and substitute another set for it.
Some men hold that the propelling car should be drawn onwards by suction, the
blades being fixed far in front, grasping the air, as it were, instead of being in the
rear pushing against the air.. This important, question, could be solved with the
described. model by having a much similar arrangement of blades, and fixing
the spiral spring far in their front instead of the rear. A decision being arrived
at as to the best set of blades for progress by suction as well as by thrust, the
best set of each would be pitted one against the other to test the comparative
value of the two very different systems.
As regards propellers of ships, the many patents taken out for their blades show
the difficulty of the subject. The solution might be much aided by inexpensive
experiments in a pond with a model constructed on the principle just described.
The greater part of the large driving wheel might be above the water.
1.1. 15th 100%
An Invention for Ascertaining by Means of a Model the Best
Number and Form to be Given to the Blades (or Fans), of
the Propellers of Navigable Balloons and of Ships.
I WILLIAM NELSON HUTCHINSON of Wellesbourne. Bideford in the county of
Devon, General in Her Majesty's Army, do hereby declare the nature of my said
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
Great doubt exists as to the best number of blades. (or fans) that should be
attached to the shafts of the propellers of navigable balloons and to the propellers

page_text: of ships also as to their size, shape, and curve-also as to what exact angle their
faces should incline. from the axis of the shaft.. This perplexing question. exists.
whatever be the nature of the power by which the shafts are driven. Much light
would be thrown upon this. subject-which is becoming one of increasing
importance as the science of aeronautics. advances-by making experiments, with
inexpensive, models constructed as follows.
To act the part of the shafts of the propellers I have two precisely similar steel
cylinders, A, see plate Figs 1 and 2, nearly,, say, 6 inches long and inch in
diameter. similarly grooved (cogged); in their whole length. They resemble what.
is termed by clockmakers "pinion wire." Fixed thin steel axles, B;.say 5 inches
long, project from both ends of each cylinder (shaft) and rotate in circular holes at
the head of similar perpendicular uprights;. C,, say, 7 inches high, a little higher.
than the radius of the driving wheel, E not yet described,; fixed about a foot apart,
each pair in the central. vertical-plane of the cylinder it supports. Both cylinders
with their respective pair of uprights are so fixed on a board, S, that the cylinders::
are. parallel to each other. The uprights. are also parallel, to each other in a
directly, transverse direction. The cylinders can move freely horizontally when:
actuated by, the. blades, (fans), D, hereafter; described: Rotation is given to:
those cylinders by a large driving wheel, E, which. plays the part of the steam.
engine or other driving power employed in navigable, balloons or ships. It is,
more than a dozen. times the diameter of the cylinders. It's periphery is so steeled
and cogged as to correspond in size with the grooves in the cylinders. It stands
midway between. the: cylinders. and, is in contact with both at, right angles to
their axes. Its axis revolves in circular holes in two uprights, F, attached. to the
board S., The operator gives revolution: to the wheel by means of a crank-.
handle, O, Figs 1 & 2.so produced towards the spiral springs, H hereafter described,.
that he can conveniently act upon it manually. The revolution of the cylinders
must manifestly be alike whatever may be the rate at which the driving wheel is
turned. The part of blades is performed by cuttings made on sheets of tin or
black iron, called in the trade Lateen: The substance of the sheets selected.
depends upon the size of the model: No more thickness is required: than: will
prevent the blades when revolving with the greatest rapidity; from yielding to the.
pressure of the wind. With the same radius I draw many circles on similar sheets,
and somewhat parallel to the direction of the radii cut differently sized nearly
complete sections; to act as the blades (or fans). No two circles are similarly cut.
I leave uncut,a, circle, G Fig. 3. about of an inch in diameter around the centre,
with a central hole to receive the short thick part, V, of the axle B at one end of
the cylinder. The open passage, R, Fig. 3, allows any of the set of blades being
placed centrically on the thin part of the said axle. P is the screw that temporarily
fastens the set of blades to the cylinder. The several blades cut on one circle of tin
are alike, but no two sets of blades are alike. By clipping I reduce the sectional
parts to any size or number I consider desirable for trial, and by digital or other
pressure easily give them any curve. To obtain the best effect different rates of
revolution require for each that an appropriate curve be given to the blade-
hence the necessity for ascertaining what is the curve most suitable for the
intended general rate of revolution. Opposite to the axis that does not carry the
set of blades there is a spiral spring, H, so arranged that when the axis is forced
against it by the action of the revolving blades it yields to the pressure. X and Y.
are two of 3 (possibly 4) equidistant, parallel, horizontal circular steel wires
within the spring, fixed to a flat upright, Z. They support the spring which
travels freely though guided by them. W, is a circular piece of tin in contact
with the spring, so pierced with as many holes as there are wires X, Y, &c that it
slides readily on them when pressed against by the axis B. The extent to which
it yields is the measure of the excellence of the blades which act on it; and is
marked by the spot to which a wire indicator, L, (as shewn by its projecting pin
travelling in a slot) retires within its sheath U fixed horizontally in the produced
line of the axis. T, is a support for the produced axis of E. To test the value of

page_text: the form and curve given to the blades and to decide upon the best number of
blades I take two sets-slip one on the axis of each cylinder-fasten them (the
sets of blades) with the screw, P, and operate upon the driving wheel, E, by
turning the crank-handle, O. I afterwards quickly remove whichever set least
succeeds in forcing home the indicator and substitute another for it. Some men
hold that the propelling car of the balloon should be drawn on by suction, the
blades being fixed in front grasping the air as it were, instead of being in the rear
pushing against the air. This important question could be solved with the
described model by having a much similar arrangement of blades but contrarily
curved, and fixing the spiral spring in their front instead of the rear, A decision
being arrived at as to the best set of blades for progress by suction as well as by
thrust, the best set of each would be pitted the one against the other to test the
comparative value of the two very different systems.
As regards the blades of balloon propellers, in testing their respective value the
force derived from gravity might be substituted for the spiral springs. If the
board S, be of an uniform thickness and perfectly rectangular, and the produced
vertical central longitudinal planes of the cylinders be parallel to the two sides of
the board, it is manifest that the tilting up of its rear part (the side adjacent to
the crank-handle, O,) will, from the force of gravity, cause both the cylinders to
equally resist being thrust back. As before, the length to which the blades
would respectively drive them back would be shewn by the indicating wire, L.
With respect to the propellers of ships, the many patents taken out for their
blades show the difficulty of the subject. The solution might probably be much
aided by inexpensive experiments made in a pond with a model constructed on
the principle just described. This would be an easy means of confirming, or
rendering doubtful by practical experiment, the accuracy of Mr Froude's deductions.
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 as
the described model (or machine) is quite a novelty what I claim is
The sole right to manufacture them substantially in the manner explained, or
to allow others to manufacture them.