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Патент USA US3053337

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Sept. 11, 1962
Filed Oct. 25, 1961
2 Sheets-Sheet 1
Paul F Ferreira
Wynn; H
Sept. 11, 1962
Filed Oct. 25, 1961
2 Sheets-Sheet 2
Paul F Ferreira
BY 2mm
United States Patent O?lice
Patented Sept. 11, 1962
Paul F. Ferreira, Box 111, Honolulu, Hawaii
Filed Oct. 25, 1961, Ser. No. 147,529
6 Claims. (Cl. 170—159)
greater linear velocity of the radial outer portions. It
is also to be noted that the back sides of the blades are
flat as shown at 18 and the forward ‘surface of the blades
are convex as shown at 29.
The ends of the blades 14 and '16 are secured to delta
or arrowhead-shaped tiups 22 and 24, respectively. Since '
the tips 22 and 24 are identical to one another, only the
This invention relates to propellers and particularly
tip 22 will be described in detail.
to propellers for aircraft.
The delta-shaped tip 22 is de?ned by a slightly convex
Brie?y, the invention comprises a propeller having an
enlarged arrolwhead shaped tip portion which has a con 10 outer leading edge 26, a slightly convex inner leading
edge 28 and a substantially radially extending trailing
cave forward face that substantially improves the effi
edge 36}.
ciency of the propeller.
The back side of the tip 22 is substantially ?at as
Accordingly, it is a primary object of the invention to
provide a propeller having extremely high e?iciency for
its diameter and pitch.
It is still another object o fthe invention to provide
a propeller which is so designed that it will efficiently ab
sorb a large amount of power particularly since its tip
speed is reduced.
shown at 3-2 and is coplanar with the ‘back surface of the
outer end portion of blade 14 as shown in FIGURE 7.
Two convex ridges 34 and 36 are formed on each side
of the forward face of the tip 22, and these ridges extend
in slightly curved paths which are parallel to the lead
ing edges 26 and 28. The forward face of the tip 22
It is still another object of the invention to provide 20 is hollowed out between the ridges 34 and 36 so as to
a propeller which will operate more ef?ciently at ex
tremely high tip speeds.
It is still another object of the invention to provide an
improved propeller which is suitable for use on aircraft,
form a concave portion 38. As shown more clearly in
FIGURES 3, 4 and 5 the concave portion 38 and the
ridges 34 and 36 gradually decrease in thickness as they
approach the trailing edge 30 so as to provide a rela
25 tively sharp trailing edge. ‘It is also to be noted that
helicopters, and marine craft.
any cross-section such as 3-3, 4—4 and 5-——5 taken
It is still another object of the invention to incorporate
through the tip 22 by a plane perpendicular to the longi
the advantages and ef?ciencies of the principles of a delta
tudinal axis of the propeller is of streamlined airfoil shape
wing ‘for use in propellers for improving the e?iciency
similar to the cross-sectional shape of the blades 14 and
thereof, particularly at the tip portions which are nor
16. Therefore, it is apparent that when the propeller
mally operated in the vicinity of sonic speeds.
rotates in a counterclockwise direction as viewed in FIG
These together with other objects and advantages which
URE 1 and indicated by the arrows R that the direction
will become subsequently apparent reside in the details
of airflow over the tip 22 is substantially parallel to the
of construction and operation as more fully hereinafter
section lines 3—3, 4—4 and 5—-5, and also the direction
described and claimed, reference being had to the ac
companying drawings forming a part hereof, wherein like 35 of flow of this air is also generally perpendicular to the
longitudinal axis 40 of the propeller. Therefore, since
numerals refer to like parts throughout, and in which:
the air ?owing over the tip portion 22 is in effect ?ow
FIGURE 1 is a front elevational view of a preferred
ing over a streamlined airfoil of the shape, shown in
form of my invention;
FIGURE 2 is an enlarged end or plan view of the
FIGURES 3, 4 and 5 the relative movement between the
surfaces of the tip
the direction of the
A port-ion of this
40 air ?owing over the tip 22 and the
propeller shown in FIGURE 1;
22 create a great amount of thrust in
FIGURES 3, 4, 5, 6, 7, 8, 9 and 10 are enlarged cross
arrows T shown in FIGURES 2.
sectional views taken on lines 3—3, 4——4, 5-5, 6*6,
thrust is created by the positive angle
7—7, 8-—8, 9-9 and 10——10, respectively on FIG
of attack of the ?at
surfaces 32 of the tip. However, most of the thrust is
URE 1.
FIGURE 11 is a front elevational view of a modi?ed 45 created by the air ?owing over the convex ridges 34
and 36 into the ‘concave portion 28. The is because in
form of my invention;
?owing over the ridges the velocity of the air is increased
FIGURE 12 is a horizontal cross-sectional view taken
thereby creating a reduced pressure on the back sides
substantially on the plane of line 12-—12 of FIGURE
of the ridges and in the depression or convex portion
FIGURE 13 is a vertical cross-sectional view taken sub
Due to the relatively large area of the tip portions
stantially on the plane of line 13—13 in FIGURE ll;
22 and 24, they obviously absorb a great deal of power
FIGURE 14 is a cross-sectional view taken substan
in relation to the blades 14 and 16 "because they are ro
tially on the plane of line 14—14 in FIGURE 11;
tating or traveling at a greater linear speed.
FIGURE 15 is an elevational View of a portion of a
The tips 22 and 24 are in effect miniature delta wings.
third form of my invention;
Therefore, they have all the advantages and characteris
FIGURE 16 is ‘a cross-sectional view taken substantially
tics of delta wings which are known to have improved
on the plane of line 16-16 of FIGURE 15; and
FIGURE 17 is a rear elevational View of a fourth form
aerodynamic characteristics at extremely high speeds,
particularly speeds in the vicinity of sound and above.
Referring to the drawings, and particularly FIGURES 60 It is to be noted that the forward surface of the outer
end of each ‘blade 14 and 16 merges smoothly into the
1 through 10, it can be seen that my propeller it} in
of my invention.
cludes a ?at circular central hub 12 and conventional
ridges 36 as shown at 42.
10, the blades are twisted so that the radially inner por
tions of the blades have a greater angle of attack or pitch
noted that the blades 14' and 16' are connected with the
trailing edges 30’ of the tips and merge and blend into
the rear end of the edges 36'.
FIGURES 11 through 14 illustrate a modi?ed form 44
propeller blades 14 and 16 projecting radially from oppo
of my propeller. The propeller 44 comprises a circular
site sides of the hub 12 ‘and formed integrally therewith. 65 hub 46 integrally formed with S-shaped blades 14’ and
The blades 14 and I16 are of ‘conventional air-foil cross
16’ of circular cross-section. These blades terminate in
sectional shape and the trailing edge and leading edge
and merge with delta-shaped tips 22’ and 24' of identical
of each blade diverge from one another in a radially
con?guration and size. The tips 22 and 24 except their
outward direction. As can be seen in FIGURES 8, 9 and
leading edges 26’ and 28’ are straight. Also, it is to be
than the radially inner portion thereof because of the
While the blades 14' and 16' are shown as being cir
conventional propeller of considerably larger diameter.
cular in cross-section it is apparent that they could be
The advantages of this are readily apparent. For ex
of streamline or teardrop cross-sectional shape.
ample, it permits the landing gear of the aircraft on
In the third form of my invention illustrated in FIG
which the propellers are used to be made much shorter
URES 15 and 16, the tips are substantially of the same
thereby saving weight and materials, and it reduces the
design and con?guration as shown in FIGURES 1 and 11.
tip speed of the propellers thereby permitting them to
One of ‘the tips is shown at 22” and differs from the other
operate more ef?ciently.
forms primarily in that a reinforcing rib‘ 48 extends longi
The foregoing is considered as illustrative only of the
tudinally down the center of the tip and projects from
principles of the invention. Further, since numerous
the forward face thereof. The rib 48 is substantially tri 10 modi?cations and ‘changes will readily occur to those
angular in cross-section and has a pointed leading edge
skilled in the art, it is not desired to limit the invention
as shown at 50. The primary purpose of the rib 48 is
to the exact construction and operation shown and de
to reinforce and strengthen the relatively thin central
scribed, and accordingly all suitable modi?cations and
portion of the tip, particularly where it is recessed as
equivalents may be resorted to, falling within the scope
shown at 38". The tips are mounted on the ends of
blades 14" which are as illustrated in FIGURE 15 circu
lar in cross-section. The blades on which the tips are
of the invention as claimed.
What is claimed as new is as follows:
1. A propeller comprising a blade, means for securing
mounted are substantially the same shape and design as
one end of the blade to a power source, the other end of
illustrated at 14’ and 16' in FIGURE 11.
said blade secured to an enlarged tip of deltoid shape,
FIGURE 11 illustrates a fourth form of my invention 20 said tip having leading edges projecting forwardly of the
which differs primarily over the previous forms in that
leading edge of said blade and converging to a point, con
the blades 14"’ and 16"’ are substantially straight in a
vex ridges formed on the forward surface of the tip paral
radial direction rather than being F-shaped as illustrated
lel to and adjacent to said leading edges of said tip.
in FIGURES 11 and 15. However, these ‘blades are
2. A propeller as de?ned in claim 1 wherein said tip
either circular or teardrop-shaped in cross-section. While
is provided with a concave area between said ridges.
the blades are shown supporting tips 22” and 24" of the
3. A device as de?ned in claim 1 wherein said ridges
same design illustrated in FIGURE 15, these tips may
and the thickness of said tip at said concave area gradually
be of the designs illustrated in FIGURES 1 and 11 if
decrease in thickness in a direction toward the trailing
edge of the tip.
The hubs of all the propellers illustrated are preferably 30
4. A device as de?ned in claim 3 wherein said blade
provided with a central bore 13 for receiving a conven
is circular in cross-section.
tional drive shaft. The hubs may also be provided with
5. A device as de?ned in claim 4 wherein said blade
conventional bores 15 (see FIGURE 1) arranged in a cir
extends in an arcuate path between said securing means
cular pattern around the central bore 13 for receiving bolts
which extend through a radial ?ange on a drive shaft.
If desired, the blades such as 14 and 15 in FIGURE 1
of the propellers may be provided with dihedral, par
ticularly if they are to be used in helicopters. By di
hedral, it is meant that the outer ends of the propeller
blades are tilted forwardly or backwardly in relation to 40
the hub 12.
By providing the propeller blades with the tips 22 and
24, it is possible to make a propeller of much smaller
overall diameter which will ‘absorb as much power as a 45
and tip.
6. A device as de?ned in claim 3 wherein a reinforcing
rib is formed on the forward surface of said tip and ex
tends ‘along the median line thereof.
References Cited in the ?le of this patent
MaKenney ___________ __ Aug. 29, 1922
Billings _____________ __ June 17, 1947
Gluhareff ___________ __ June 13, 1950
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