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WO2001074658A2 - Helice marine - Google Patents

Helice marine Download PDF

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Publication number
WO2001074658A2
WO2001074658A2 PCT/US2001/009828 US0109828W WO0174658A2 WO 2001074658 A2 WO2001074658 A2 WO 2001074658A2 US 0109828 W US0109828 W US 0109828W WO 0174658 A2 WO0174658 A2 WO 0174658A2
Authority
WO
WIPO (PCT)
Prior art keywords
blades
hub
blade
marine propeller
propeller
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2001/009828
Other languages
English (en)
Other versions
WO2001074658A3 (fr
Inventor
David J. Gruenwald
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
POWER VENT TECHNOLOGIES Inc
Original Assignee
POWER VENT TECHNOLOGIES Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/539,993 external-priority patent/US6390776B1/en
Application filed by POWER VENT TECHNOLOGIES Inc filed Critical POWER VENT TECHNOLOGIES Inc
Priority to AU2001249520A priority Critical patent/AU2001249520A1/en
Priority to PCT/US2001/009828 priority patent/WO2001074658A2/fr
Publication of WO2001074658A2 publication Critical patent/WO2001074658A2/fr
Publication of WO2001074658A3 publication Critical patent/WO2001074658A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • B63H1/26—Blades

Definitions

  • This invention is directed to the marine industry and in particular to multi-blade propellers.
  • the propulsion system on a boat is one of the most important aspects of boat design, yet least understood. There are variety of items that make up the propulsion system and numerous items that affect how well the propulsion system works.
  • the propeller remains the most critical aspect of the propulsion system. Shaft angle, boat trim, stern gear, boat weight, engine horsepower and gear ratio are but a few items that affect propeller performance and behavior.
  • a major concern of propeller design is the amount of vibration that the propeller will produce while under way. As a general rule, in order to minimize vibration the number of blades on the propeller should be increased. There is no particular limit to the number of blades a propeller may have however, costs increase with the number of blades while the gain in reduction of vibration decreases with each additional blade.
  • a negative consequence of increasing the number of blades on the propeller is the progressive reduction of efficiency of the propeller while operating in reverse to back down the boat .
  • Another major concern in propeller design is cavitation.
  • Cavitation is a partial vacuum caused by excessive propeller speed or loading. The vacuum causes bubbles to form and implode irregularly causing uneven pressure on both sides of the blades resulting in vibration that feels like an, unbalanced or unequally pitched blades. Further, the force of imploding bubbles can actually pull materials off the surface of the propeller leading to pitting, uneven wear, and resulting in bad balance and additional vibration.
  • propellers are mounted aft of the transom except in cases like Small U.S. Patent No. 4,689,026 where the propeller operates in a tunnel.
  • a disadvantage to these types of propellers is their inability to provide sufficient reversing thrust.
  • the blade shape required for high efficiency at speed in a super cavitating design inhibits reversing properties that are normal to the typical propeller. This is caused by two factors. First, the blade has a progressive pitch which means that the pitch gets progressively higher as it approaches the trailing edge of the blade. When used in reverse, the trailing edge has too much pitch for efficient operation. Second, the trailing edge of a super cavitating propeller is sharp because, in forward, it is desired to have the flow of water separate from the blade efficiently.
  • the instant invention is directed toward a marine propeller with increased performance in reverse but without decreased performance in forward, having a hub and a multiplicity of blades extending radially outward from the hub.
  • the separation of these blades about the hub lessens interference between the blades and increases the efficiency of the propeller. Interference between adjacent blades may be reduced by decreasing the number of blades or increasing the length of certain blades beyond the length of other blades or increasing the diameter of certain blades beyond the diameter of other blades. Accordingly, it is an object of this invention to provide a multi-blade propeller with improved performance for backing down a boat . It is a further object of this invention to decrease the interference of each propeller blade with the performance of the blades directly adjacent to it while operating in reverse.
  • Another object of this invention is to provide multi-blade propellers with a portion of the trailing edge of some of the blades further aft than the trailing edges of the other blades. It is a further object of this invention to provide a propeller with blades having different widths. It is a further object of this invention to provide a propeller with a modified trailing edge. It is a further object of this invention to provide the trailing edge of the blades with a shallow concavity.
  • Fig. 1 shows a partial elevation of a propeller having blades o'f differing widths
  • Fig. 2 shows a partial elevation of a propeller having blades with different diameter on the same hub
  • Fig. 3 shows a partial elevation of a propeller having blades with a modified trailing edge
  • Fig. 4 shows a cross section of a modified blade along line 4 - 4 of Fig.3.
  • a boat propeller 10 is shown with only two blades for simplicity. Also, the blades are shown without pitch so they appear flat. These propellers may be made with any number of blades on a hub.
  • the blades of these multi-blade propellers are disposed symmetrically about the hub, for example, the blades of a four bladed propeller are ninety degrees apart and a ten blade propeller has blades 36 degrees apart.
  • the forward end of hub 11 has a keyway 12 into which a drive shaft (not shown) is fitted. The drive shaft transmits the power from the engine (s) to the propeller.
  • the blade 13 has a leading edge 14 and trailing edge 15.
  • the trailing edge 15 intersects the leading edge 14 defining the blade surface.
  • the length of the blade is determined as the distance from hub to the point where the leading edge and trailing edge intersect.
  • the width of the blade is determined as the distance from the leading edge to the trailing edge at a fixed radius from the hub.
  • the chord of the blade is, in general, the thickness of the blade at its thickest point.
  • the blades of the propeller have a high pressure side and a low pressure side.
  • the high pressure side of the blade is the forward or leading side in the direction of the rotation of the propeller.
  • the low pressure side of the blade is the following or back side.
  • the blades of the propeller are designed to operate most efficiently in forward gear with the high pressure side leading in the direction of rotation.
  • the low pressure side becomes the leading side.
  • the surface R of the blades is the low pressure side and initially contacts the water in reverse. This denotes a rotation of the blades, in reverse, toward the viewer of the Figures.
  • the blade 16 has a leading edge (not shown) which is shaped identically with leading edge 14 and extends from the hub in the same plane as the leading edge 14.
  • Blade 16 has a trailing edge 17.
  • Blades 13 and 16 have the same profile in length and chord. Blade 13 has a width w which is less than the width w' of blade 16. While Fig.
  • a propeller with eight blades may have four alternating blades with one width and the other four blades with a greater width while a propeller with nine blades may only have three blades with a greater width than the others.
  • the only prerequisite is that the propeller must remain balanced.
  • the trailing edge 17 and any other blade with a greater width W cuts into undisturbed water because the blade which preceded it is now behind it in the axial direction.
  • the ventilation bubble created by each wider blade is separated from the next wider blade by the number of intervening blades. Since the interference on the wider blades is reduced, the propeller becomes more efficient in reverse.
  • propeller 30 has hub 31 with a keyway 32.
  • Blade 33 has a leading edge 34, a trailing edge 35 a ⁇ .d a length L.
  • Leading edge 38 of blade 36 extends from the hub 31 in the same plane as the leading edge 34 of blade 33.
  • Blade 36 has a trailing edge 37, a leading edge 38 and a length L f .
  • blade 36 has a greater length than blade 33.
  • Blade 36 and blade 33 can have the same profile in width and chord or they can have different width and chord as shown. As stated above, the blades shown in the Fig. 2 are adjacent but in practice there can be a number of blades interposed between the longer and/or wider blades.
  • the modification to the blades to increase reverse efficiency is on the trailing edge of the propeller blade.
  • the trailing edge modification is kept inside an imaginary extension of the high pressure surface 49 and an imaginary extension of the low pressure side of the blade 50 (shown in Fig. 4) .
  • Fig. 3 shows a marine propeller with a hub 41, a keyway 42, and a blade 43.
  • the blade 43 has the same profile in width, length and chord.
  • the leading edges 44 of the blades extend from the hub in the same plane.
  • the trailing edge of blade 43 has an addendum 51, shown in Fig.
  • the modified blades with the addendum 51 or radius to smooth the flow of water in the reverse direction of rotation reduce the tendency to form a ventilation or cavitation bubble on the low pressure side of the blade because the water is flowing around a smooth radius rather than a sharp edge, thereby increasing the' bite of the modified blades.
  • the blade with the addendum or radius may be on every blade, on alternate blades or oft any combination of blades as long as the entire propeller remains balanced.

Landscapes

  • 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

L'invention concerne une hélice marine ayant une meilleure performance en marche arrière. L'hélice comporte un moyeu et plusieurs pales radialement saillantes. Une partie des bords arrières d'une partie ou de la totalité des pales est modifiée afin de réduire les interférences entre les pales et d'augmenter le mordant desdites pales lorsqu'elles fonctionnent en marche arrière.
PCT/US2001/009828 2000-03-30 2001-03-26 Helice marine Ceased WO2001074658A2 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2001249520A AU2001249520A1 (en) 2001-03-26 2001-03-26 Marine propeller
PCT/US2001/009828 WO2001074658A2 (fr) 2000-03-30 2001-03-26 Helice marine

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US09/539,993 US6390776B1 (en) 2000-03-30 2000-03-30 Marine propeller
US09/539,993 2000-03-30
PCT/US2001/009828 WO2001074658A2 (fr) 2000-03-30 2001-03-26 Helice marine

Publications (2)

Publication Number Publication Date
WO2001074658A2 true WO2001074658A2 (fr) 2001-10-11
WO2001074658A3 WO2001074658A3 (fr) 2002-05-02

Family

ID=26680449

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/009828 Ceased WO2001074658A2 (fr) 2000-03-30 2001-03-26 Helice marine

Country Status (1)

Country Link
WO (1) WO2001074658A2 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4689026A (en) 1985-08-26 1987-08-25 Small Mark S Propeller tunnel baffle and method

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR671016A (fr) * 1928-03-31 1929-12-07 Perfectionnements aux ailes de roues à hélice pour propulseurs, turbines, pompes, moulins à vent ou appareils analogues
DE1113386B (de) * 1960-06-18 1961-08-31 Zeise Theodor Fa Voll kavitierendes Profil, insbesondere fuer Schiffspropeller
DE1919086A1 (de) * 1969-04-15 1970-12-17 Schneekluth Dr Ing Herbert Schiffs-Schraubenpropeller mit Fluegeln ungleicher Radien
JPS6150893A (ja) * 1984-08-17 1986-03-13 Kobe Steel Ltd 舶用プロペラ
US4789306A (en) * 1985-11-15 1988-12-06 Attwood Corporation Marine propeller
JPH03292286A (ja) * 1990-04-09 1991-12-24 Takayoshi Sato 回転翼

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4689026A (en) 1985-08-26 1987-08-25 Small Mark S Propeller tunnel baffle and method

Also Published As

Publication number Publication date
WO2001074658A3 (fr) 2002-05-02

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