Propeller test data

Discussion in 'Props' started by Ben Land, Apr 22, 2020.

  1. Ben Land
    Joined: Mar 2015
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    Ben Land Junior Member

    Hi,
    I am interested in creating a database of different propellers on different applications and results.
    I have few magazines with some outboard test results in them.
    Can anybody suggest a publication(s) with extensive propeller test results.
    I am interested in the following:
    Displacement / Semi-displacement / planing craft
    Inboard / outboard

    Thanks in advance.
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I think that magazines usually publish marketing tests. You would need controlled tests in equal conditions to compare propellers scientifically.
     
  3. Ben Land
    Joined: Mar 2015
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    Location: Finland

    Ben Land Junior Member

    hi Gonzo,

    I understand this but the meaning for the database is just to have a rough idea of the general prop characteristics used in range of applications and what kind of results does it lead to roughly. I am not making any serious decisions based on the data, it is there just for reference.
    Hence some degree of error can be tolerated.

    Could Signinficant Small Ships of Rina be useful?
     
  4. bajansailor
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    bajansailor Marine Surveyor

  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I think the value of that compilation would be to find the average propeller for a particular boat.
     
    bajansailor likes this.
  6. Alan Gilbert
    Joined: May 2020
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    Location: Port Washington, NY

    Alan Gilbert Junior Member

    I do not completely understand what you are asking. Are you interested in knowing the performance of the prop for a range of speed regimes, or the performance of a propeller driving a specific hull form at a given speed. While the two might be cousins the approach used in the determination is often very different.

    First and foremost I would not rely on advertised published data, as if everything is not defined, for example wind/sea conditions, test weight, running trim angle, position of trim tabs, etc. you may end up comparing apples with oranges. While third party tests by let say publications are better, you must take care that everything that impacts the results is defined.

    So I am guessing at some general comments which may or may not be responsive. In order to determine the dynamic characteristics of a propeller only, tests are undertaken in a towing tank or water tunnel. Many series have been tested and are available such as Troost, VanLammaren (sp?) etc. The generic propeller characteristics are determined by the speed it is to be optimized to. For example in very very high speed applications one must go to a super cavitating design, as a typical low speed prop would behave like a paint mixer as speed increases, meaning a lot of fuss but little forward thrust. Once the appropriate generic prop type is determined, the optimum propeller is a function of the resistance characteristics of the vessel, the speed, and the installed delivered engine horsepower and shaft rpm delivered to the propeller.
     

  7. Ben Land
    Joined: Mar 2015
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    Location: Finland

    Ben Land Junior Member

    Hi Alan thanks for your input.

    I was just interested in putting some very rough data in an excel sheet (e.g. lwl, displacement, trial speed, propeller dia, pitch, etc etc... Nothing scientific. Just some rough references for personal interest.

    Actually I got the whole idea when I run up to this yearly publication where boats are tested with different outboards and propellers. I started to think that it would be interested to see if there are similar publications of also other propulsor types and to maybe collect some of the data in an excel sheet etc.

    Have a great weekend
     
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