New Propeller Innovation: Looking for Comment/Interested Parties

Discussion in 'Boat Design' started by moobradidi, Aug 24, 2016.

  1. moobradidi
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    moobradidi Junior Member

    I am looking for parties who may be interested in a new development in propeller technology currently in the patent process.

    Background

    All existing propellers in aviation, marine and industrial applications are a compromise in terms of their diameters/blade length. Larger propellers are more efficient at low vehicle speed but limit maximum speed due to the braking/drag effect of the larger disk area. Smaller propellers can deliver greater cruise and maximum speed but are not optimal at low speed where thrust needs to be maximised.

    The ideal propeller would have the ability to vary its disk area (within limits) to suit both the rpm of its energy source at any given instant, as well as the vehicle's velocity at that instant and also to meet a range of operational and environmental conditions that may exist.

    This goal has existed for a while and a number of research outfits have patented or are still pursuing this goal- including research in variable length rotors.

    An example of recent work (in aviation) is here: https://www.deepdyve.com/lp/institu...n-of-a-variable-diameter-propeller-wmUsYfPZqn

    While the above is recent it is not at all impressive.

    Our new approach is mechanically simple and robust but remains complex in determining its performance, reliability etc

    There are 4 versions which exist as solidworks CAD models. Each of these models has been implemented in aircraft, marine, outboard motor and industrial fan versions.

    The range of diameter variation they offer ranges from 14% to 20% depending on version. This fully overs the minimum-maximum diameter possible in most applications of fixed props.

    Other versions allow blade angle and blade diameter to be controlled JOINTLY. That is, a single mechanism simultaneously increases/decreases blade length while also actuating blade angle. In this version, diameter and blade angle cannot be independently varied.

    However this makes sense in some applications such as outboard motors where advancing the control lever with the throttle would advance the prop from maximum diameter and fine pitch to minimum diameter and coarse pitch. This alleviates operator workload and optimises the combination of rpm, diameter and pitch at any given moment.

    To get a more visual idea go to

    www.ndjen.com

    and play 2 animations there. While they don't reveal the actual mechanisms involved, sine they are outputs from the CAD models they do show that the range of pitch and diameter claimed is demonstrably real.

    Note that the animations suggest that the pitch and diameter changes are in steps/discrete. This is not so. Pitch and diameter are infinitely variable in these designs within their minimum and maximum constraints.

    Interested parties should contact

    admin at ndjen.com.

    More detailed video files are available. We are interested in feedback/issues/comments which are constructive- especially from those with backgrounds that can assist. However, all constructive comment- commercial, legal or related to the realities of such a development would be more than welcome.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Existing outdrives and outboards don't have much scope to be increasing the diameter beyond the standard propellor fitted. In those cases, you would want to be able to alter pitch without changing diameter.
     
  3. moobradidi
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    moobradidi Junior Member

    Thanks fpr your reply but I don't understand the limit you mention. Is it a limit on the HP available? Is it a physical limit on the size of the prop that can be accomodated?

    Given that boat owners change the size of their props all the time and so do boat owners, we are only providiing the same variation they can buy at the store and fit on their boats. But we provide it with the shift of a lever.
     
  4. moobradidi
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    moobradidi Junior Member

    The designs clearly allow the provision of variable pitch and in a simple way that has not been previously possible (without hydraulics).

    But the addition of diameter change totally optimises thrust for any speed and engine rpm setting.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    How do you increase diameter without a purpose-designed drive, when you will run into clearance issues ?
     
  6. moobradidi
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    moobradidi Junior Member

    Clearance between what and what? The difference between the size of the smallest prop fitted on an outboard for example is 3-4 inches.

    You go to the boat store. You say "I think I need a smaller prop for speed". He looks up a chart. He says the smallest prop your motor will run is X inches and Y pitch.

    You say. Changed my mind. I want a prop for fast takeoff and loitering. He says "no probs, the largest prop your motor will run is Z inches and M pith".

    Our system provides the same choices.

    What am I missing here?

    There are no clearance issues involved in either choice.
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    3-4 inches ? No, I'd say 2 inches diameter difference at most. Probably less in most cases. You would have to factor that in.
     
  8. moobradidi
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    moobradidi Junior Member

    Let's put this another way.

    You an fit large prop A to your motor because the manufacturer says you can.

    Or

    You can fit small prop B because the manufacturer says u can.

    They have no clearance issues.

    Our diameter variation is the same as the difference between A and B.

    We can design it so that the largest diameter will never exceed A and the smallest will never b smaller than B.

    No clearance issues.
     
  9. moobradidi
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    moobradidi Junior Member

    We can make the variation as little or as large as you like.

    The real problem with earlier patents in this area has been that the range of variation possible was minimal, complex to implement and unreliable.

    In general the problem has not been too much variation in the mechanism but too little.
     
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    Looking at the unit on the website, it clearly isn't one that would apply easily to an outboard/sterndrive.
     
  11. moobradidi
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    moobradidi Junior Member

    The outboard version is in fact very elegant and the animations on the site don't reveal it.

    Suffice to say that the standard mechanism that is used in most outboards to shift gear is simply replicated twice. In other words two vertical control shafts are used. One controls pitch and the other diameter.

    In versions where pitch and diameter are linked, there is a single push/pull control rod which changes pitch and diameter jointly. All of this is contained in a standard lower unit housing.

    Pitch changes range from fine to feather and to reverse in all versions.

    The aircraft versions are more complex because they have to go to feather pitch automatically in an emergency. This is done either with a redundant hydraulic system (most common way) or blade counterweights and springs (a cheaper, older way, more common on light aircraft).
     
  12. moobradidi
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    moobradidi Junior Member

    The marine version shown in animation on the website uses a blade for a larger vessel but a smaller, more appropriate profile can be made to fit.
     
  13. FAST FRED
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    FAST FRED Senior Member

    The unit will need to be automatic as with too much diameter the engine can be overloaded which can reduce its life drastically.

    Rec trawler folks are petrified of installing a cruising prop that would better match the thrust required with the thrust available at lower engine speeds.

    IF it measures EGT or some measure of engine load it would be an easier sell, and safer product for the public.
     
  14. gonzo
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    gonzo Senior Member

    I clicked on the link, and it only has an animation without any technical information. Do you have any explanation on how the mechanism works, or is it simply a vague idea?
     

  15. Skyak
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    Skyak Senior Member

    I think it will be a 'tough sell' to the boat guys. They tend to put the max diameter prop on and are extremely suspicious of reliability. I can not recall ever wanting to reduce prop diam except for clearance issues. Feathering benefits and reliability are clearer and yet they are suspect.
     
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