IMPROVEMENTS IN TESTING SCREW PROPELLERS AND PADDLE WHEELS
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by Jeffries Kingsley at the Office
of the Commissioners of Patents, with his Petition, on the 7th June
1860.
I, JEFFRIES KINGSLEY, of 52, Great Coram Street, in the County of Midde-
sex, Lieutenant on Half-pay of Her Majesty's Third Regiment of Dragoons,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
TESTING SCREW PROPELLERS AND PADDLE WHEELS," to be as follows:-
With the view to test the efficiency of any screw propeller or paddle wheel,
either absolutely according to a pre-conceived standard, or by comparison with
screw propellers of different forms and constructions, I purpose to use a small
experimental boat or vessel, which may be built or constructed in any suitable
manner; or by preference might be an exact model of the vessel in which it
is desired to adopt a screw propeller.
The screw propeller (the model for experiment) may be attached to the
outer extremity of the shaft which projects from the stern of the above boat.
A brass box may be fastened on the deck, similar in principle to the brass box,
mainspring, chain and escapement of a watch; the mainspring may com-
municate with the inner extremity of the aforesaid shaft. In the above
construction it is obvious that the mainspring represents the steam engine of

page_text: the experimental frigate, the escapement regulating the number of rotations
which the propeller must complete on its axis, within, say, ten minutes, the
time generally assigned for each experiment, when the brass box will go down
of its own accord. Should it be determined that the propeller shall perform
50 rotations on its own axis within one minute of time, then the brass box
may be regulated accordingly; of course the escapement may be removed
from the brass box when its machinery may require another arrangement.
Regarding the motive power imparted to the mainspring it may measure the
one-half part or the entirety of a steam engine of one-horse power, as may be
deemed fit. To use the above for testing purposes I adopt this mode:-
Assuming that 24 screw propellers, A, B, C, &c., also Y, varied in weight,
form, dimensions, and the number of their blades, were attached to the
aforesaid boat each for ten minutes, whereupon it was ascertained that 1,466
yards, 1 foot and 11 inches was the maximum velocity which was imparted to
the boat, which measurement was accomplished by Y: Therefore, it is obvious,
that the aforesaid propeller was the best amongst the alphabeted lot, and,
therefore, that model may be judiciously enlarged and adopted, being
economically cast at the foundry in its entirety suitable for war steamers
of all rates, at least until a better propeller shall be provided, the probabilities
of its exceeding 1466-666 yards of 5 miles per hour being in favour of that
accomplishment. Or the propeller, par excellence, may be also arrived at
thus: A leaden trough, annular in form, may be embedded in the earth, and
when supplied with water, the aforesaid boat, brass box, and propeller may be
floated thereon. In order to maintain the keel in the perpendicular direction,
and to cause the boat to move within the same circle, an iron rod may be
provided. An aperture may be made in one extremity thereof, which may be
received by an upright post planted in the centre of the circle, the other
extremity being attached to the boat, the distance travelled by that vessel
being the measure of the propeller. when compared with the 1466 666 yards
already accomplished by Y; or, in other words, should it not exceed that
measurement, the model may be thrown aside as useless, the loss sustained
being a trifle. With the exception of weakness in a propeller which may not
come within the range of the exact sciences, the best propeller may be also
obtained by the following modifications of the above:-1st, the said brass box
may be firmly secured to a block of wood in the perpendicular direction, the
propeller being attached to the outer extremity of another. shaft provided for
that purpose, the fronts of the blades being in a plane perpendicular to the
plane of the horizon, the whole representing a windmill. Secondly, a steel

page_text: spring and its index may be placed adjacent to either extremity of the shaft,
which must move freely backwards and forwards in a line parallel with its
axis; the weight or pressure on the steel spring by the extremity of the shaft,
as shewn by the index, may attest the fitness of the propeller.
Propellers may be tested by the aid of the following modification," com-
bined or not with the said brass box, namely, a reservoir of suitable depth and
diameter may be formed in the earth, the interior being lined with wood, so
as to prevent the water percolating. Mercury may, if preferred, be substituted
for water; but if water be used, it should be saturated with salt or other
suitable material. A lid or cover may be provided, in the centre of which an
aperture may be made, through which the outer extremity of the shaft may
pass, and to which extremity the propeller may be attached, the fronts of the
blades being undermost in the plane of the horizon, when the lid or cover may
be firmly secured to the wood, on which lid the brass box may be stationed.
The steel spring with its index may be also attached to the lid, the shaft
moving freely upwards. As the propeller whilst rotating on its axis must
ascend in the reservoir in the perpendicular direction, the weight or pressure
of the upper extremity of the shaft on the steel spring, as marked by the
index, may attest the pretensions of the propeller.
:-
Or the following inodification may be applied to test screw propellers
first, an iron rod (square) may be procured, one extremity of which may be
attached to the roof of a lofty building, the same being produced within one
yard of the pavement; secondly, the rod may pass through a balloon inflated
with bydrogen gas, a tube being inserted within the balloon for that purpose;
thirdly, an aperture may be made along the line of the axis of the shaft and
of the propeller through which the rod may also pass, the fronts of the blades
being undermost in the plane of the horizon; fourthly, the upper extremity of
the brass box may be attached to the lower extremity of the balloon; finally,
a weight may be attached to the lower extremity of the iron rod; the weight
of the apparatus being counterbalanced by the means of the hydrogen gas,
insomuch that the brass box and propeller may remain stationary at whatever
height they might be placed by the experimenter. As all friction regarding
the ascent of the apparatus is removed, experiments may be followed up with
the greater accuracy. It is also evident that the motive power of the-brass box
may be increased by adding steel to the mainspring, also admitting of the
propeller being increased in its weight, and of being enlarged in its dimensions
by increasing the cubical capacity of the balloon. The rapidity of the ascent
of the brass box from the pavement to the roof may recommend the character

page_text: of the propeller. The whole of this arrangement may be inverted. The screw
may be tested by fastening one extremity of an iron rod (square) to any fixture
above the surface of the water of a lake or reservoir, the other extremity
being submerged therein. The rod may pass through an air-tight vessel by
means of a gutta percha tube; an aperture may be made along the line of the
axis of the shaft, and of, the propeller through which the rod may also pass,
and the lid of the brass box may be attached to the lower extremity of the
air-tight vessel. The front of the propeller, which is undermost, being in the
plane of the horizon; lastly, a weight may be attached to the lower extremity
of the rod, the weight of the apparatus being counterbalanced by means of
the air-tight vessel, the rapidity of the ascent of the brass box from the
weight to the surface denoting the value of the propeller. Or the air-tight
vessel may be removed, as exemplified by the removal of the balloon in the
preceding statement. It is also obvious that the propeller might be sub-
merged in a deep well or in a long tube containing mercury, or it might be
tested at the foot a high fall of water, as, for instance, the Falls of Niagara.
Or a railway may be used instead of the above, on which four light wheels
may be laid from both axles of which a carriage may be raised, on which the
brass box and propeller may be stationed, the fronts of the blades being in a
plane perpendicular to the plane of the horizon. Here it is obvious that the
carriage represents the experimental vessel, the main spring of the brass box
performing the duty of its steam engine, causing the propeller to rotate on its
axis with extraordinary rapidity, the air of the atmosphere (instead of water)
being the resistance which must be overcome by the front of the propeller;
the vessel itself instead of being pillowed on the wave must travel on hard iron,
the maximum distance travelled being the value of the propeller. Regarding
the testing the malconstruction of screw propellers, as to the weakness or over-
weighting thereof, with the view of discovering the above imperfections, appa-
ratus above described might be usefully applied to some of these purposes.
But the machines now used to test chain cables, iron rods, &c., might be
preferred, as they are better known; therefore a reservoir may be provided
with a moveable cover. An aperture in the horizontal direction may be made
in either end of the reservoir through which an iron shaft may pass, and to
the extremity of which the propeller may be attached, the same being wholly
submerged in the water highly saturated with salt or suitable material when
the cover may be bolted down on the reservoir. A glass tube open at both
extremities may be inserted in the cover in the perpendicular direction, as may
be deemed fit. And the above machine for testing chain cables may commu-

page_text: nicate with the outer extremity of the shaft, causing the propeller to rotate
on its axis with extraordinary rapidity, which may be made manifest by the
ascent of the water in the glass tube. The force or the test applied to the
propeller may be also measured by the above machine on a principle similar
to that of ascertaining the strength of chain cables.
The above is a description of the nature of the said Invention, which might
probably be varied in practice as regards its details.