Improvements in Screw Propellers for Preventing Slip in Water and Air.
Year: 1898

page_text: Date of Application, 6th Sept., 1898
Complete Specification Left, 6th July, 1899-Accepted, 6th Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in Screw Propellers for Preventing Slip in Water
and Air.
FREDERICK BUCHANAN, Engineer, Closewoods, Denmead, near Cosham, Hants,
do hereby declare the nature of this invention to be as follows:-
Propeller blades are evenly and finely groved or corrugated in a direction
transverse to stroke or radius of propeller at a certain or given angle the angle
of groves will vary according to diameter of propeller, an approximate would
be about sixty °.
Doted this 3rd day of September 1898
Improvements in Screw Propellers for Preventing Slip in Water
and Air.
I, FREDERICK BUCHANAN, of Closewoods, Denmead, near Cosham, in the County
of Hants, 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 present invention relates to screw propellers for use in either water or
air, the object being to so construct form or arrange the blades of the same that
slipping thereby becomes more effectively prevented than is possible with pro-
peller blades as hitherto formed or constructed to attain which I form or con-
struct the surfaces of each propeller blade with a series of evenly arranged finely
formed grooves, channels or cuts which run in a transverse direction to the
propelling movement of the blades and at an angle thereto of about sixty
degrees.
:
My invention however will be more fully and perfectly understood by refer-
ring to the accompanying sheet of drawings and the following description
thereof in which Fig. 1 is a front elevation of my improved propeller and Fig. 2
a side elevation of same. Similar letters of reference denote corresponding
parts in each view.
Each blade A is formed with a series of fine grooves a¹ which run parallel to
each other and cover the whole of the surface of each said blade, and each said
groove a runs in a direction transverse on each blade A and at an angle of
sixty degrees or thereabouts at an opposite inclination to the propelling move-
ment or working forward action of the blades A as shown at Fig. 1 where the
blades A move to the right when propelling a boat forward through air or water

page_text: or in other words the grooves a run across the blades A at an angle of 60° to
a base line s taken square with a central radial lines through blades. It will
be obvious that the grooves channels or cuts a¹ may be formed by strips or pro-
jections being fastened to the surfaces of the blades A instead of being cut
therein as shown.
I
I find by practical test that by the use of these grooves, channels or cuts a¹
the blades A grip hold of the air or water and a better propelling effect is pro-
duced than is possible to be obtained with propellers as hitherto formed there-
fore
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. Arranging the surfaces of screw propeller blades with a series of parallel
grooves, channels or cuts or strips forming same which run transversely at an
angle of sixty degrees or thereabouts thereon substantially as described and for
'the object specified.
:
2. In screw propellers for use in water or air the combination of a series of
channels, grooves, cuts or strips running angularly upon the surfaces of the
blades with said propeller blades substantially as described and illustrated.
Dated this 5th dot of T. 1900
H. F. BOUGHTON,
Patent Agent, 114A, Chancery Lane, London, W.C.
H. F. BOUGHTON,
Patent Agent, 114A, Chancery Lane, London, W.C.