US3606579A - Propeller - Google Patents

Propeller Download PDF

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Publication number
US3606579A
US3606579A US792972*A US3606579DA US3606579A US 3606579 A US3606579 A US 3606579A US 3606579D A US3606579D A US 3606579DA US 3606579 A US3606579 A US 3606579A
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Prior art keywords
blade
propeller
main
slot
main blade
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Expired - Lifetime
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US792972*A
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Henry Mehus
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/28—Other means for improving propeller efficiency
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/18—Propellers with means for diminishing cavitation, e.g. supercavitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H2001/145—Propellers comprising blades of two or more different types, e.g. different lengths

Definitions

  • This invention relates to propellers, particularly marine screws, but also propellers for fans and the like, having two or more blades.
  • the primary object of the invention is to provide a propeller having a high efficiency, and more particularly the invention relates to a propeller wherein the main blade is provided with an auxiliary blade located at the discharge edge of the main blade when going forward, and the novel features according to the present invention consist in the following: that in an arbitrary axis parallel cylinder section through the blades the pitch on the blades is dened by helical lines through the terminal points of the longitudinal center lines of these sections, and that the helical lines through the terminal points of the cylinder sections of the auxiliary blade at the same radius have the same or a larger pitch than the helical lines of the main blade, and that the helical lines of the auxiliary blade are located abaft of the helical lines of the main blade relative to the forward speed of the vessel.
  • the number of such pair of blades may vary from two to any proper number.
  • the slot between the main blade and the auxiliary blade serves the following purpose:
  • water air, gas or the like
  • the slot which according to the equation of Bernoulli create an under-diminished pressure at the discharge edge of the main blade, whereby the water flow at Ythe suction side of the main blade is prevented from loosing.
  • the common undesired turbulence on the suction side of the propeller blade is avoided.
  • the area of ⁇ the auxiliary blade is maximum half of the area of the main blade.
  • the main blade and the auxiliary blade may be formed in one single piece, the blades being separated by a slot sloping astern and being limited by a por-tion of the pressure side of the main blade at its discharge edge and a portion of the suction side of the auxiliary blade at its inlet edge, when the Vessel is going forward, corresponding to the direction of flow of the Water.
  • the main blade and the auxiliary blade may be arranged with a forwardly directed cast, and the auxiliary blade may be revolving.
  • FIG. 1 illustrates the propeller, seen in the forward direction of the vessel, i.e. from the end of the hub;
  • FIG. 2 is a displayed cylinder section along line II-II 3,606,579 Patented Sept. 20, 1971 in FI-G. 1, illustrating a main blade and an auxiliary blade, and indicating the pitchs helical lines and a, respectively;
  • FIG. 3 is a longitudinal sectional view through the hub and the pair of blades along the lines IIIa-IIIa and IIIb-IIIb in FIG. 1;
  • FIG. 4 is a view similar to FIG. 2, but illustrating a modified embodiment, in which the main blade and the auxiliary blade is made in one single piece.
  • the reference letter f (FIGS. 1 and 2) indicates the forward direction of the vessel, While d is indicating the rotation direction of the propeller.
  • Each of the two blades (main blades) 1 of a propeller is provided with an auxiliary blade 2 located at the discharge edge of the associated main blade 1, assuming the -vessel is moving forward.
  • auxiliary blade 2 located at the discharge edge of the associated main blade 1, assuming the -vessel is moving forward.
  • an arbitrary axis parallel cylinder section e.g. II-II in FIG. 1
  • the pitch on the blades is dened by helical lines through the terminal points of these sections longitudinal center lines.
  • the helical lines through the terminal points of the cylinder sections of the auxiliary blade 2 (see FIG. 2) at the same radius have according -to lFIG.
  • auxiliary blade 2 a larger pitch than the helical lines of the main blade 1; this being illustrated on the drawing by the fact that a is larger than
  • the helical lines through the terminal points of the center line of the cylinder sections of the auxiliary blade 2 may at the same radius be equal to those of the main blade with respect to the pitch, confer FIG. 4 in which the main blade 1" and the auxiliary blade 2' are made in one single piece, a slot 4 being provided in order to separate the blades.
  • a plate piece 5 is welded to the main blade 1" in order to overlap the auxiliary blade 2' at the slot opening.
  • the helical lines of the auxiliary blade are located abaft of the helical lines of the main blade 1 by forward motion of the vessel.
  • the reference numeral 3 indicates the hub and 1' the inlet edge of the main blade by going forward.
  • the slot between the main blade and the auxiliary blade is 4 and 4', respectively.
  • the auxiliary blade can be made revolving (not shown), which can be achieved by any of a number of known methods.
  • the auxiliary blade 2, 2 and the main blade 1, 1" have cast forwardly (see FIG. 3).
  • a propeller suitable for use as a marine screw having a hub and a main blade and an auxiliary blade on said hub, said main blade and said auxiliary blade both slope forwardly with respect to the forward direction of travel of a vessel propelled by said propeller, said auxiliary blade having a maximum of one-half the area of the main blade, said auxiliary blade being disposed adjacent the discharge end of the main blade and overlapping the trailing edge of the main blade with the pressure side of the main blade facing the suction side of the auxiliary blade, whereby a slot is formed between said auxiliary blade and the trailing edge of said main blade, the auxiliary blade and said main blade being so proportioned that the slot has a length of about 0.6 times the radius of the main blade and a width of 0.06 to 0.09 times the width of the main blade, and the pitch angle of said auxiliary blade being at least equal to the pitch angle of said main blade.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

A PROPELLER OF THE MARINE SCREW TYPE HAVING A MAIN BLADE AND AN AUXILIARY BLADE LOCATED AT THE DISCHARGE END OF THE MAIN BLADE, SAID BLADES HAVING A SLOT RUNNING THEREBETWEEN AT THE TRAILING EDGE OF THE MAIN PROPELLER BLADE. THE WIDTH OF THE SLOT IN CROSS SECTIONAL AREA REDUCES ITS SIZE FROM THE PRESSURE SIDE OF THE BLADE TOWARDS THE SUCTION SIDE OF THE BLADE TO CREATE A THROTTLE EFFECT RESULTING IN AN INCREASE IN WATER FLOW VELOCITY THROUGH THE SLOT AND A REDUCTION OF THE PRESSURE IN THE SUCTION SIDE OF THE PROPELLER. THE STRUCTURE SO PRESENTED REDUCES CAVITATION

AND IMPROVES PERFORMANCE OF THE PROPELLER BY REDUCING TURBULENCE ON THE SUCTION SIDE OF THE PROPELLER BLADE.

Description

Sept. 20, 1971 H. MEHus 3,606,519
PROPELLER Filed Jan. 22, 1969 INVENTOR BY f/AVMM United States Patent Office 3,606,579 PROPELLER Henry Mehus, Kampens plass 12, Stavanger, Norway Filed Jan. 22, 1969, Ser. No. 792,972 Int. Cl. B63h 1/26 U.S. Cl. 416-200 1 Claim ABSTRACT F THE DISCLOSURE tion side of the blade to create a throttle effect resulting in an increase in water tlow velocity through the slot and a reduction of the pressure in the suction side of the propeller. The structure so presented reduces cavitation and improves performance of the propeller by reducing turbulence on the suction side of the propeller blade.
This invention relates to propellers, particularly marine screws, but also propellers for fans and the like, having two or more blades.
The primary object of the invention is to provide a propeller having a high efficiency, and more particularly the invention relates to a propeller wherein the main blade is provided with an auxiliary blade located at the discharge edge of the main blade when going forward, and the novel features according to the present invention consist in the following: that in an arbitrary axis parallel cylinder section through the blades the pitch on the blades is dened by helical lines through the terminal points of the longitudinal center lines of these sections, and that the helical lines through the terminal points of the cylinder sections of the auxiliary blade at the same radius have the same or a larger pitch than the helical lines of the main blade, and that the helical lines of the auxiliary blade are located abaft of the helical lines of the main blade relative to the forward speed of the vessel.
The number of such pair of blades (main and auxiliary blade) may vary from two to any proper number.
The slot between the main blade and the auxiliary blade serves the following purpose: When the propeller rotates, water (air, gas or the like) will be urged in the direction of rotation along the pressure side of the main blade and through the slot, which according to the equation of Bernoulli create an under-diminished pressure at the discharge edge of the main blade, whereby the water flow at Ythe suction side of the main blade is prevented from loosing. Thereby the common undesired turbulence on the suction side of the propeller blade is avoided.
The area of `the auxiliary blade is maximum half of the area of the main blade.
The main blade and the auxiliary blade may be formed in one single piece, the blades being separated by a slot sloping astern and being limited by a por-tion of the pressure side of the main blade at its discharge edge and a portion of the suction side of the auxiliary blade at its inlet edge, when the Vessel is going forward, corresponding to the direction of flow of the Water.
In some instances it may be advantageous to arrange the main blade and the auxiliary blade with a forwardly directed cast, and the auxiliary blade may be revolving.
The propeller according to the invention will be further described by way of example in connection with the accompanying drawings, in which:
FIG. 1 illustrates the propeller, seen in the forward direction of the vessel, i.e. from the end of the hub;
FIG. 2 is a displayed cylinder section along line II-II 3,606,579 Patented Sept. 20, 1971 in FI-G. 1, illustrating a main blade and an auxiliary blade, and indicating the pitchs helical lines and a, respectively;
FIG. 3 is a longitudinal sectional view through the hub and the pair of blades along the lines IIIa-IIIa and IIIb-IIIb in FIG. 1;
FIG. 4 is a view similar to FIG. 2, but illustrating a modified embodiment, in which the main blade and the auxiliary blade is made in one single piece.
In the drawings the reference letter f (FIGS. 1 and 2) indicates the forward direction of the vessel, While d is indicating the rotation direction of the propeller.
Each of the two blades (main blades) 1 of a propeller is provided with an auxiliary blade 2 located at the discharge edge of the associated main blade 1, assuming the -vessel is moving forward. In an arbitrary axis parallel cylinder section, e.g. II-II in FIG. 1, through the propeller blades 1, 2 the pitch on the blades is dened by helical lines through the terminal points of these sections longitudinal center lines. The helical lines through the terminal points of the cylinder sections of the auxiliary blade 2 (see FIG. 2) at the same radius have according -to lFIG. 2 a larger pitch than the helical lines of the main blade 1; this being illustrated on the drawing by the fact that a is larger than The helical lines through the terminal points of the center line of the cylinder sections of the auxiliary blade 2 may at the same radius be equal to those of the main blade with respect to the pitch, confer FIG. 4 in which the main blade 1" and the auxiliary blade 2' are made in one single piece, a slot 4 being provided in order to separate the blades. A plate piece 5 is welded to the main blade 1" in order to overlap the auxiliary blade 2' at the slot opening.
The helical lines of the auxiliary blade are located abaft of the helical lines of the main blade 1 by forward motion of the vessel.
On the drawings the reference numeral 3 indicates the hub and 1' the inlet edge of the main blade by going forward. The slot between the main blade and the auxiliary blade is 4 and 4', respectively.
Preliminary experiments have shown that very good results were obtained when the slot 4 or 4' had a width in the axial direction of approximately 0.06-0.09 times that of the main blade by 0.6 of the radius of the main blade.
If desired, the auxiliary blade can be made revolving (not shown), which can be achieved by any of a number of known methods. In the shown embodiment the auxiliary blade 2, 2 and the main blade 1, 1" have cast forwardly (see FIG. 3).
What I claim is:
1. A propeller suitable for use as a marine screw having a hub and a main blade and an auxiliary blade on said hub, said main blade and said auxiliary blade both slope forwardly with respect to the forward direction of travel of a vessel propelled by said propeller, said auxiliary blade having a maximum of one-half the area of the main blade, said auxiliary blade being disposed adjacent the discharge end of the main blade and overlapping the trailing edge of the main blade with the pressure side of the main blade facing the suction side of the auxiliary blade, whereby a slot is formed between said auxiliary blade and the trailing edge of said main blade, the auxiliary blade and said main blade being so proportioned that the slot has a length of about 0.6 times the radius of the main blade and a width of 0.06 to 0.09 times the width of the main blade, and the pitch angle of said auxiliary blade being at least equal to the pitch angle of said main blade.
(References on following page) 4 References Cited FOREIGN PATENTS UNITED STATES PATENTS 68,480 1941 Czechoslovakia 416-231 176,842 3/ 1922 Great Britain 416-231 lgfg @ggg 851,524 10/1960 Great Britain 416-231 Faber 5 7/1936 Vargas 170-172 3/1939 Baker 170 172 EVERETTE A. POWELL, JR., Prxmaly Exammer 5/1939 Barnett 170-172 XR Tl-.Smel 10 CL l l 4/ 1966 Saunders 416-231 6/1968 Grebe 416-200X
US792972*A 1969-01-22 1969-01-22 Propeller Expired - Lifetime US3606579A (en)

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3767324A (en) * 1969-06-11 1973-10-23 D Ericson Fan apparatus
WO1982002694A1 (en) * 1981-02-13 1982-08-19 Guenther Spranger Method and device for decreasing the flow resistance on wings particularly aerofoils,and blades of turbomachines exposed to gaz flux such as air
US4512718A (en) * 1982-10-14 1985-04-23 United Technologies Corporation Tandem fan stage for gas turbine engines
EP0255136A1 (en) * 1986-07-31 1988-02-03 Mitsui O.S.K. Lines, Ltd. A screw propeller boss cap with fins
US4840540A (en) * 1987-06-27 1989-06-20 Deutsche Forchungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.V. Propeller whose blades are provided with slats
US5236307A (en) * 1991-07-27 1993-08-17 Rolls-Royce Plc Variable geometry rotors for turbo machines
EP0916574A3 (en) * 1997-11-12 2001-04-25 Adalbert Zwirchmayr Propeller
WO2010046502A1 (en) * 2008-10-24 2010-04-29 Creaidea B.V. Propeller for gas displacement apparatus
NL2004618C2 (en) 2010-04-27 2011-10-28 Brain Mining Factory B V Propeller for liquid displacement apparatus.
US20130129514A1 (en) * 2011-11-18 2013-05-23 Becker Marine Systems GmgH & Co. KG Propeller arrangement, in particular for watercraft
US20130209224A1 (en) * 2012-02-10 2013-08-15 Mtu Aero Engines Gmbh Turbomachine
US20130259693A1 (en) * 2012-04-03 2013-10-03 Yih-Wei Tzeng Ship propeller
US20190185143A1 (en) * 2017-12-19 2019-06-20 Wing Aviation Llc Fiber Sheet Stacked Rotor Design

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3767324A (en) * 1969-06-11 1973-10-23 D Ericson Fan apparatus
WO1982002694A1 (en) * 1981-02-13 1982-08-19 Guenther Spranger Method and device for decreasing the flow resistance on wings particularly aerofoils,and blades of turbomachines exposed to gaz flux such as air
US4687416A (en) * 1981-02-13 1987-08-18 Spranger Guenther Method and device for decreasing the flow resistance on wings particularly aerofoils and blades of turbomachines exposed to gas flux such as air
US4512718A (en) * 1982-10-14 1985-04-23 United Technologies Corporation Tandem fan stage for gas turbine engines
EP0255136A1 (en) * 1986-07-31 1988-02-03 Mitsui O.S.K. Lines, Ltd. A screw propeller boss cap with fins
GB2194295A (en) * 1986-07-31 1988-03-02 Mitsui O S K Lines Ltd Screw propeller boss cap
FR2619352A1 (en) * 1986-07-31 1989-02-17 Mitsui O S K Lines Ltd PROPELLANT PROPELLER HUB HAT WITH FINS
AU593670B2 (en) * 1986-07-31 1990-02-15 Mikado Propeller Co., Ltd. A screw propeller boss cap with fins
GB2194295B (en) * 1986-07-31 1991-03-20 Mitsui O S K Lines Ltd A screw propeller
US4840540A (en) * 1987-06-27 1989-06-20 Deutsche Forchungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.V. Propeller whose blades are provided with slats
US5236307A (en) * 1991-07-27 1993-08-17 Rolls-Royce Plc Variable geometry rotors for turbo machines
EP0916574A3 (en) * 1997-11-12 2001-04-25 Adalbert Zwirchmayr Propeller
WO2010046502A1 (en) * 2008-10-24 2010-04-29 Creaidea B.V. Propeller for gas displacement apparatus
NL2004618C2 (en) 2010-04-27 2011-10-28 Brain Mining Factory B V Propeller for liquid displacement apparatus.
TWI510407B (en) * 2011-11-18 2015-12-01 Becker Marine Sys Gmbh & Co Kg Propeller arrangement, in particular for watercraft
US20130129514A1 (en) * 2011-11-18 2013-05-23 Becker Marine Systems GmgH & Co. KG Propeller arrangement, in particular for watercraft
JP2013116727A (en) * 2011-11-18 2013-06-13 Becker Marine Systems Gmbh & Co Kg Propeller arrangement, in particular for watercraft
US9328613B2 (en) * 2011-11-18 2016-05-03 Becker Marine Systems Gmbh & Co Kg Propeller arrangement, in particular for watercraft
US20130209224A1 (en) * 2012-02-10 2013-08-15 Mtu Aero Engines Gmbh Turbomachine
US10184339B2 (en) * 2012-02-10 2019-01-22 Mtu Aero Engines Gmbh Turbomachine
US20130259693A1 (en) * 2012-04-03 2013-10-03 Yih-Wei Tzeng Ship propeller
US20190185143A1 (en) * 2017-12-19 2019-06-20 Wing Aviation Llc Fiber Sheet Stacked Rotor Design
US10689095B2 (en) * 2017-12-19 2020-06-23 Wing Aviation Llc Fiber sheet stacked rotor design
EP3728025A4 (en) * 2017-12-19 2021-09-08 Wing Aviation LLC STACKED ROTOR DESIGN FROM FIBER WEB
US11214356B2 (en) * 2017-12-19 2022-01-04 Wing Aviation Llc Fiber sheet stacked rotor design
EP4253038A3 (en) * 2017-12-19 2023-12-20 Wing Aviation LLC Fiber sheet stacked rotor design

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