Improvements in the Construction of Screw-propellers for Vessels.
Year: 1889

page_text: Date of Application, 27th Mar., 1889
Complete Specification Left, 27th Dec., 1889-Accepted, 8th Feb., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Screw-propellers for Vessels.
We MAX VOGELGESANG and JOHN HILLRIE BONN both of Hoboken, County
Hudson State of New Jersey United States of America Engineers do hereby declare
the nature of our said invention to be as follows:-
The object of our invention is to provide a screw propeller for vessels by the use of
which a smoother and steadier motion and a more effective working of the same is
obtained-even at high speeds.
In carrying out our said invention we construct a screw propeller the blades of
which are secured to the hub at an angle of inclination to the axis of the same and are
slightly concaved on their working faces towards the cutting edges of the blades, the
said cutting edges are made with an obtusely angled projection or nose, which is
connected, by a short inclined ridge, to a longitudinal ridge forming inclined ridges
at the rear side of each blade, so as to conduct the water passing between them parallel
or nearly so with the working faces of the blade and so producing an increased.
effectiveness and a steady motion of the propeller.
The concavity on the working faces of the blades above referred to is greatest at
the point of greatest width of the blade, from which it gradually diminuishes towards
the hub and the point of the blade.
The action of our improved propeller is as follows:
When the propeller is rotated in the direction of the screw, the angular front or
cutting edges cut through the water and conduct it between the blades along the
before mentioned inclined faces at the rear of the blades and over the longitudinal
ridges towards the straight rear edges of the blades in such a manner that the water
is passed through between the blades in a direction nearly parallel to the working
faces of the blades, so that the said working faces are very little if at all affected by
the backwardly moving body of water forced through between the blades of screw.
Dated this 27th day of March 1889.
POPPLEWELL, COLTON & Co.,
17 & 18, Sonthampton Buildings, London, W.C.
COMPLETE SPECIFICATION.
Improvements in the Construction of Screw-propellers for Vessels.
We MAX VOGELGESANG and JOHN HILLRIE BONN both of Hoboken County
Hudson State of New Jersey United States of America Engineers 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
--
This invention relates to improvements in the construction of screw-propellers for
vessels by which a more effective working of the propeller and a steadier and smoother
motion of the same even at high speeds is obtained and the said invention consists of a
scrow propeller the blades of which are secured to the hub at an angle of inclination to the
axis of the same and slightly concave on their working faces towards the cutting edges
of the blades, which cutting edges are made with an obtusely angled projection or
nose that is connected by a short inclined ridge with a longitudinal ridge which ridges
form inclined faces at the rear side of each blade so as to conduct the water parallel
or nearly so with the working faces of the blades and produce an increased effectiveness
and a steady motion of the propeller.
In the accompanying drawings
Figure 1 represents a perspective view of our improved screw propeller.

page_text: Figures 2 & 3 are respectively a rear view of one of the blades and a side elevation
of the same; and
Figure 4 is a side view of one of the blades of the propeller screw shewing different
cross sections of the same taken on lines. parallel to the axis of the screw, said cross
sections being developed into vertical plane with the section lines at the base
thereof.
Similar letters of reference indicate corresponding parts.
A A represent the blades of our improved screw propeller and B the hub of the
same. The blades A are arranged at an angle of inclination to the axis of the hub as
customary in screw propellers.
.
The working faces a of each blade A is slightly concave towards the front or cutting
edge of the same, the degree of concavity being clearly indicated in the cross sections
taken at different points of the blade as shewn in Figure 4. The greatest concavity
in the working face a of the blade is arranged at the point of greatest width of the
blade A from which the concavity of the face diminishes gradually towards the hub
and point of the blades.
The front or cutting edge of each blade is made in the shape of an obtuse
angle so as to form a projection or nose which is located at the point of the greatest
width of the blade A. From this projection or nose b, extends at the rear side of the
blade an inclined transverse ridge b, c the inner edge of which is connected with the
hub B and the point of the blade by a longitudinal ridge d, c, e as shewn in Figures 2
and 4.
The ridges b, c and d, c, e form with the edges of the blade A three slightly concave
faces that incline from the point of greatest thickness formed at the intersection of the
transverse ridge b, c with the longitudinal ridge d ce. By the rotation of the blade
on the axis of the hub in the direction of the arrow shewn in Figure 2 the angular
front or cutting edges cut through the water and conduct it between the blades along
the inclined faces b c d and bee at the rear of the blades and over the longitudinal
ridges d ce towards the straight rear edges of the blades in such a manner that the
water is passed through the blades in a direction nearly parallel or at least a very
oblique angle to the working faces a of the blades, so that said working faces are very
little if at all affected by the backwardly moving body of water forced through
between the blades of the screw. The inclined guide faces formed on the rear sides
of the blades serve thus to impart to the body of water that is forced through between
the blades during the forward motion of the vessel, a clearly defined direction which
is parallel or nearly so to the working faces of the blades.
It is conceded that the inclined guide faces formed by the longitudinal and trans-
verse ridges at the rear sides of the blades exert a certain resistance against the
forward motion of the screw in axial direction and cause thereby a small loss of power
to the same but practical tests made with our improved screw have clearly established
that this small loss of power is more than compensated by the decreased slip produced
by the direction imparted to the water in passing between the blades by which the
water moves off in a direction parallel to the working faces and produces thereby not
only a greatly increased working effect of the screw but also an easier and smoother
motion of the same.
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 :-
First: A screw propeller the working faces of which are arranged at an angle to
the axis of the propeller and slightly concaved towards the obtusely angled front of
the cutting edges of the blades which latter are reinforced at their rear sides and an
inclined transverse ridge and a longitudinal ridge extending from the inner end of
the transverse ridge towards the hub and point of the blades so as to form inclined
guide faces by which the water passing over the ridges is conducted off in a direction
nearly parallel to the working faces of the blades substantially as set forth.

page_text: Second-A screw propeller having radial blades inclined to the axis of the propeller
and obtuse angled front or cutting edges and inclined guide faces formed at the rear
sides of the blades by an inclined transverse ridge and a longitudinal ridge that
extends from the inner end of the transverse ridge towards the hub and the point
of the blades substantially as set forth.
Dated this 27th day of December 1880.
POPPLEWELL, COLTON & Co.,
17 & 18, Southampton Buildings, London, W.C., Agents for the Applicants.