Flapping inverting foil (patent pending)

Discussion in 'Boat Design' started by frogger1225, Sep 7, 2014.

  1. SamSam
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    SamSam Senior Member

    Well, you're right in that it doesn't look impressive. If you're trying to impress, you need to make a different video. Using a flimsy, broken system doesn't do it, especially when in the background the kayaks make 5 or 10 times the distance with 2/3 the strokes.

    "So who's interested" in what? Discussion or are you looking for investors?

    Maybe you could post the patent numbers of any prior art you uncovered that you think might be relevant.
     
  2. SailDesign
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    SailDesign Old Phart! Stay upwind..

    Sorry - just not seeing a "huge" transfer of energy. If there was, those spindly tubes would have buckled long ago.

    However, I wish you every success - I have been wrong before, and am fully prepared to believe it will happen again. :)

    And again....
     
  3. Jeremy Harris
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    Jeremy Harris Senior Member

    This isn't correct. I hold a few patents and I can assure you, beyond any doubt, that even if a poor patent office grants a patent to an idea that has prior art (and in this case there is masses of prior art, all in the public domain) then it is a worthless patent that cannot ever be defended.

    In this case there are many people who have designed, built, tested and used flipper propulsion systems just like this. Few have been patentable (and all those that have been put in the public domain cannot now be patented anyway, because of the disclosure), some have made it to commercial products (at least two or three, but none have sold well, or have suffered from engineering problems).

    Finally you need to measure, not just claim, efficiency. It's easy to do, just measure the power input at the handles and the propulsive output that's driving the hull. If you get better than about 60% from a properly engineered system with low friction bearings and carefully optimised foils I'll be frankly amazed, as even very well engineered moving fin systems have struggled to get to this sort of efficiency.

    The quote about fish efficiency is (please excuse the pun) a red herring. Fish fins are pressure adaptive and adjust their profile and velocity to give the best propulsive efficiency by optimising the pressure distribution across their surface. Fish can do this because they can sense local pressure across the surface of a fin, and use this to adjust both the fin movement and, in the case of some species, their skin/scale orientation to control boundary layer effects.

    Finally, the 80% figure applies to one experimental study on one fish species that is optimised for high speeds. It is far from being a generic figure for fin efficiency, and most fins probably struggle to get better than 50% efficiency.
     
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  4. Doug Lord
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    Doug Lord Flight Ready

  5. Jeremy Harris
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    Jeremy Harris Senior Member

    I agree, Doug, the Hobie is far and away the best and most reliable fin drive system. I think it may have been Rick Willoughby (I wish that guy was still on this forum) who did some work on the efficiency of the Hobie system, and IIRC, it was somewhere less than 50%. Having said that it works well and is so close to the efficiency of oars or paddles, and so much easier to drive, that it is generally a pretty good option. The only real downsides are the inability to go astern and the relatively high draft if the fins are put through their full range of motion (although you can limit the pedal stroke to keep them up closer to the hull in shallow water).

    The Harry Bryan Thistle fin drive seems to work OK (http://www.harrybryan.com/harrybryan/ThistlePlan.html) but like other lateral fin drives suffers from the relatively high energy loss from accelerating and decelerating the fin at each stroke and has the added problem of inducing a yawing moment that absorbs power in steering corrections.

    The Power Fin (https://www.youtube.com/watch?v=dtv-5t8F29U) suffers from the same power losses and yaw problems, but is nevertheless reasonably effective.

    As an example of poor efficiency, this similar flapping foil system (https://www.youtube.com/watch?v=6U_IMxdWPPI) actually quotes 2 mph for 100W, which indicates an efficiency for that boat of perhaps 1/2 that of paddles or oars.

    I can't find a link to it at the moment, but there was one rather well engineered twin fin system that was developed, I think, by a university team a few years ago. This arrangement was quite clever, in that it cancelled out the yaw moment (so removed that as a cause of power loss) and also used a linkage that controlled the acceleration and deceleration rate of both fins on each stroke to reduce those losses. Additionally, by placing the fins in a tandem arrangement, the aft most fin could take some advantage of the vortices being shed from the fore most fin, gaining a little bit of extra energy recovery. I can't recall the efficiency they were getting, but think it got pretty close to 60%, which isn't at all bad.
     
  6. portacruise
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    portacruise Senior Member

    I am trying to get a handle on the meaning of efficiency numbers. For example, are they scaled to the whole system including the boat, the whole drive part or just the fin part of the whole drive? If the efficiency is 60% and one puts in 100 watts, does that mean 60 watts maximum driving forward at the water, with the lightest/fastest possible hull and under ideal flat water, no wind conditions?

    PC



     
  7. gonzo
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    gonzo Senior Member

    Efficiency means that if you input 100 into a system and it uses 50 to move the boat forward, the value is 50%. The output can be calculated by the resistance of the hull at a measured speed.
     
  8. frogger1225
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    frogger1225 Junior Member

    Alternating pitch of a symmetrical foil ...
    IMO nice but still does not catch the vortex and less high frequency is employed. Also mechanically complicated. many versions seen by me

    http://youtu.be/l1JCBwp2RnY?list=UU9QEY7zoDdziWgD0kQ7ydMw

    Gotta love the swim fins attached to the oar !! I am totally against swim fins. The only people who can use fins properly are ballerinas who are used to standing on their pointed toes (IMO!).

    I'll reserve comment due to lack of complete story. subscription?

    Fig 1. looks similar to this...with alternating pitch foil
    http://www.seajogger.com/


    http://video.mit.edu/watch/proteus-the-penguin-boat-2975/
    I am not a penguin :)
    BTW The US navy ship that I worked on had 4 propellers with 70000 shaft horsepower per shaft.... Power provided by me, the reactor operator :)


    [​IMG]
    [/QUOTE]
    The flippers are designed to.... but didn't? haven't seen much on this.

    Looks like a double hobie...

    Looks like a double hobie...

    Sculling made simple....
    http://youtu.be/MhrQ8yDnnm4

    The problem I have with bikes is that when I go to the gym to see people really work out, they use the nautilus equipment like leg press and butterfly press. The bicycle is a good platform for turning essentially linear motion into rotational motion.

    A good video would have the kayak sinking (Just kidding paddlers)

    Discussion and determining interest level.
    The art goes back a long ways. I have a list of around 50 or so that I researched thru USPTO. Searched almost every patent in the following areas outlined in attachment.

    I tried to outline the data with the pic attached... hope it helps. Operator power is completely estimated based on age !!

    I don't control the patent office.

    Agree almost completely.
    Try this... look at the webbing in between your fingers..Notice the taut bridge created at the "trailing edge"... this is where my idea stems from.

    Hobie maniacs...I love you because you will be the hardest to please but I welcome the challenge just like the one guy did on video at the boat show with the tug of war :)

    As for human power and efficiency and speed, it is all relative but the bike/propeller/lifting foil combination evidence says at max power output and peak efficiency you can get to around 20 mph with a well conditioned (not me) athlete putting out somewhere around 1 horsepower.
     

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  9. Jeremy Harris
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    Jeremy Harris Senior Member

    As already mentioned, efficiency is power in versus power out, where power out is the propulsive power delivered to propel the boat. Most props rarely get much better than 50 to 60%, for reasons that are usually to do with the compromises made to restrain draft, operate with adequate low speed manoeuvring thrust or reduce fouling from weed etc. As we both know, an optimised prop for a specific performance point can fairly easily give around 80% efficiency, but there are drawbacks in these other areas.

    Just so you know I'm a scientist, who worked in aerodynamics for much of my career. I've also spent a lot of time developing high efficiency, low power, small boat propulsion systems as a hobby, and most of them have been tested experimentally to see how the performance compares to theory.

    There is already one tandem fin system that does make use of energy recovery from the vortex shed from the first fin, I'm pretty sure there's a video of it, with details, in the pedal boat threads somewhere, but I don't have the time or inclination to go and find it right now. Suffice to say that I admire your enthusiasm, but to spend money trying to patent something that many others have done before, and published, is a bit like chucking money in the ocean, as if you're granted a patent then it won't be enforceable and will have no value. At a guess there are thousands of unenforceable patents, many granted in the past few years because, for some reason, the US Patent office, in particular, seems very lax when it comes to granting patents for things where there is pre-existing prior art. Patent agents are supposed to find all prior art and tell the inventor so the specific claims he/she is making can be carefully defined as being different and novel, but sadly few seem to bother as far as one-man-band inventors are concerned.

    If you want to waste your money on getting a worthless patent then I'm sure you'll just go ahead; all several here are doing is pointing out that you don't have anything novel to patent, based on what you've said and posted here.
     
    Last edited: Sep 9, 2014
  10. frogger1225
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    frogger1225 Junior Member

    I've attached a very simple pic of prop performance. If you want to run at top speed, then yes >80. I don't know about you, but most boaters that I know are slow to mid speed cruisers who do want to get fast speed for short periods (to chase down kayakers LOL)


    Boy, aren't you a pleasant belly full of discouragement without providing one bit of data to show cause. BTW any patent lawyer knows it is the responsibility of the party filing for patent to do complete and thorough prior art search. DONE that. Patent pending means that I have done a comprehensive search and have already staked my claim. Luckily you're not a lawyer. The patent filed by me covers the construction of the fin/blade/paddle/wing. I have thoroughly researched the patents by Hobie as well as many others from swimfins, to ladies hand fans, to one that looked so much like a bat I just had to laugh.
     

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  11. portacruise
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    portacruise Senior Member

    Thanks everyone for your responses.

    PC
     
  12. BMcF
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    BMcF Senior Member

    I can certainly vouch for that from fairly recent first-hand experience. And those thousands of improperly issued patents are what feed the "patent trolling" extortion racket in a big way. We were "attacked" by one of those trolls a few years back, named along with several other companies in similar marine businesses, with a demand that we pay back royalties and fees for "violating" a pile of patents for various ship control and stabilization "inventions". The patents were all legitimate, in the sense that they were all legally issued and rightfully owned, but all were issued despite the preponderance of prior art and practice...what we (and the others named) had developed and been selling for many years - in some cases even decades - prior to the issuance of the patents in question.

    Seeing how often patents are handed out for things that were put to practice long before has been the reason I've lost all confidence in the patent process and, frankly, for that reason never bother to even attempt to protect our designs with patents.

    And there is a "flip side" too...at least two of our clients over the years have developed truly novel hull forms and obtained, at great expense, US and International patents on those....only to sit by helplessly as others stole parts or sum of their invention and they had to admit they had no where near the resources required to enforce their patent(s).

    But back to specifically the subject at hand....I'm always rooting for the underdog and the inventor, so I'll always wish them success. :)
     
  13. portacruise
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    portacruise Senior Member

    Incompetence of the patent office may not be the worst thing. Something which is lucrative has essentially no protection, though deep pockets help. Business planning may be more important than the patent itself.
    See an informative post #16 on this thread: http://www.boatdesign.net/forums/bo...ful-general-arrangement-patented-50761-2.html

    PC

     
  14. Jeremy Harris
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    Jeremy Harris Senior Member

    Go read the pedal boat thread, or even the efficient electric boat thread. There is an absolute mountain of data and evidence there to show that low speed propellers are more efficient than high speed ones and proof by many of us who've been refining them over the years The reason is very straightforward, and is related to a whole host of factors, the main one limiting very high speed prop efficiency being cavitation and the entrainment of surface air, which is one reason why clever ways have been found to reduce blade loading (and hence local pressure difference across the blade) by using partially immersed props on high speed craft.




    No need to be offensive, all several here are doing is pointing out prior art. Portacruise has found the particular tandem fin I was thinking of, the Pacific tail boats system. I think you will find that that, along with masses of other published (but probably not patented) similar devices constitutes enough prior art to make your patent unenforceable.

    I personally think, as has already been mentioned, that the patent system (particularly that in the US) is seriously broken, as it provides little protection for one-man-band inventors who do have novel ideas and is just a means for lawyers to earn money. It's wrong that patents for things that already exist can be granted, as all it does is waste people's money.
     

  15. johnhazel
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    johnhazel Senior Member

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