Marine propulsion – With indicator
Reexamination Certificate
2000-01-05
2001-05-08
Basinger, Sherman (Department: 3617)
Marine propulsion
With indicator
C340S984000
Reexamination Certificate
active
06227918
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is an improvement over the system described and claimed in my U.S. Pat. No. 5,928,040, issued Jul. 22, 1999. This invention relates to the operation of a vessel having a propeller, and more particularly to a system for determining and displaying the real-time apparent slip and angle of attack for the vessel's propeller, as well as recording the same information for analysis at a later time.
Theoretical propeller advance in a non-yielding fluid is equal to the propeller's pitch multiplied by the number of rotations of the propeller. Apparent slip is the percentage of theoretical propeller advance lost in a yielding fluid, such as water or air. While apparent slip is not a direct measure of propeller efficiency, there is a strong correspondence between the two quantities. All other things being equal, as apparent slip is reduced, vessel speed increases.
Angle of attack is the difference between the theoretical and actual blade path for a rotating propeller blade. Angle of attack is necessary for a rotating propeller blade to generate the thrust also known as “lift”) that moves the vessel. The angle of attack of a propeller blade causes a pressure differential between the opposite-facing surfaces of the propeller blade in the same manner that a wing or hydrofoil creates a pressure differential above and below the wing or hydrofoil as it moves through air or water. A propeller having no angle of attack will provide no thrust. The optimum range of angle of attack for a propeller blade is between about 3° and 5°. A propeller operating outside of this optimum range may cause excessive propeller slip or may cause the vessel's engine to operate outside the manufacturer's recommended range of engine speeds.
Traditional systems for monitoring motor vessel performance focus on the fuel efficiency of the motor vessel engine. None of these traditional systems provide an accurate measurement of apparent slip and angle of attack.
In propeller-driven vessels (e.g., fishing boats, water ski boats, remotley-controlled model airplanes and boats, and commercial and private airplanes), apparent slip and angle of attack are important factors in overall vessel performance. For some professional, personal, and recreational activities, the apparent slip and angle of attack of the vessel's propeller directly impact the success one might have in those activities.
For example, in sports fishing, most tournaments are structured such that all teams are allotted the same amount of time on a body of water. It is in a fishing team's interest to have a fishing boat equipped with a propeller that is operating with optimal apparent slip and angle of attack. The team that can move from location to location on the water the fastest, and therefore spend the greatest portion of its allotted time fishing, has the best odds of catching a greater number of large fish and winning the tournament.
Therefore it is desirable to provide a system that measures and records data relating to propeller apparent slip and angle of attack, and that allows comparison of apparent slip and angle of attack for different propellers and under different conditions.
SUMMARY OF THE INVENTION
The invention provides a system for measuring propeller apparent slip and angle of attack for a propeller-driven vessel moving through a fluid medium. The system includes means for determining the vessel speed, means for determining engine speed, and a main console. Vessel speed is preferably determined by a pitot tube and pressure transducer or by any other reliable means. Engine speed is preferably determined by an inductive pickup interconnected with a spark plug wire, or by any other reliable means.
The main console houses a processor that is programmed with algorithms for determining apparent slip and angle of attack, and is also programmed to measure elapsed time. The main console may include a display screen on which any one of the input quantities or elapsed time can be displayed at a given time. The processor receives input data, uses the data to determine apparent slip and angle of attack for the vessel's propeller, and may display apparent propeller slip and/or angle of attack on a display screen. The measured and calculated values for apparent slip and angle of attack are used to determine on a substantially instantaneous or real-time basis the effect an adjustment of the vessel's operating parameters (e.g., tilt and height of the engine in a marine application) has on the apparent slip and angle of attack of the vessel's propeller.
The system also includes a recording feature for recording inputs and outputs to and from the processor, as well as elapsed time, for later analysis. Therefore several different propellers may be tested, and the test data may be stored to later determine which propeller operates at the best relative apparent slip and angle of attack. Also, test data for apparent slip and angle of attack as affected by changing vessel parameters (e.g., tilt and height of the engine in marine applications) can be recorded to determine the optimal settings for such parameters.
The system also includes a data downloading feature that allows for downloading of data stored in the processor to a data logger so the data can be transferred to a computer for further analysis. Processor memory can then be cleared to allow for more testing and recording.
One object of the present invention is to determine and display real-time propeller apparent slip and angle of attack information.
Another object of the present invention is to provide data for determining the optimal settings for various vessel parameters to obtain the optimal apparent slip and angle of attack for a given propeller.
Another object of the present invention is to provide data that can be used to compare the apparent slip and angle of attack of different propellers on a given vessel under the same or similar conditions and vessel parameters.
Another object of the present invention is to allow for recordation of real-time information relevant to propeller apparent slip and angle of attack for later analysis.
Another object of the present invention is to provide a method for determining the optimal settings for various vessel parameters to obtain the optimal apparent slip and angle of attack for a given propeller.
Another object of the present invention is to provide a method for comparing the apparent slip and angle of attack of different propellers on a given vessel under the same or similar conditions and vessel parameters.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.
REFERENCES:
patent: 3287965 (1966-11-01), Brahm et al.
patent: 3686485 (1972-08-01), Wiley et al.
patent: 3906437 (1975-09-01), Brandwein et al.
patent: 3960012 (1976-06-01), Ingram
patent: 3972224 (1976-08-01), Ingram
patent: 4152645 (1979-05-01), Bendler
patent: 4334425 (1982-06-01), Crane
patent: 4459671 (1984-07-01), Teass et al.
patent: 4475380 (1984-10-01), Colovas et al.
patent: 4787053 (1988-11-01), Moore
patent: 4843575 (1989-06-01), Crane
patent: 5043727 (1991-08-01), Ito
patent: 5142473 (1992-08-01), Davis
patent: 5928040 (1999-07-01), Wharton
patent: 5997250 (1999-12-01), Carter, Jr. et al.
Basinger Sherman
Michael & Best & Friedrich LLP
Wharton Mark E.
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