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#1
08-27-2009, 04:59 AM
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| Jacques Juan propellers What do you think about this? http://www.youtube.com/watch?v=8QE3Q0PbOWA The BPT Concept, developed by the french Jacques Juan, is a patented geometry for marine propellers said to reach very high efficiencies. Does someone have more information on this man and his propellers? Cheers.
__________________ Guillermo Gefaell Gestenaval S.L., Naval Architecture & Marine Engineering Moon Yacht Design  |
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#2
08-27-2009, 05:13 AM
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| From the pic's it seems that he is using some kind of tip winglets, which in itself is not new; they are known to give an improvement over conventional tips in certain operating conditions. BUT: the improvements refer to what original levels? Are the original props really optimum for the job? I want hard facts before I believe in drydock tales! |
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#3
08-27-2009, 06:17 PM
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| Absolutely. Difficult to believe such claims, that's why I'm wondering if somebody has more info. Cheers.
__________________ Guillermo Gefaell Gestenaval S.L., Naval Architecture & Marine Engineering Moon Yacht Design |
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#4
08-27-2009, 07:32 PM
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| If he has really managed to re-invent the winglets, it's amazing how he did it by starting from some completely wrong premises... Citing just few claims from the video: "A large part of the water is flung outward through centrifugal forces and (is) lost for the propulsion. ... The water rebounces off the hull, developing vibrations... (etc)" An illustrative snapshot taken from the video: |
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#5
08-27-2009, 08:07 PM
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| Yes, see what you mean. "42%" savings...compared to what? "3 times less fuel"...than what....?...why not use his prop on the boats that use 3 times more fuel for a proper qualitative test? "noticed 20%" savings....i notice many things, does this make it qualitative to be factual? again all very anecdotal. And as you say beackmo, nothing new, re cupping/winglets. I did like the look of the moules mariniere though  |
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#6
08-28-2009, 03:35 AM
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| I think he confounds efficiency with slip. When he talks 90% efficiency I think he's talking about a 10% slip, not about the propeller performance.  Cheers.
__________________ Guillermo Gefaell Gestenaval S.L., Naval Architecture & Marine Engineering Moon Yacht Design |
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#7
08-28-2009, 04:34 AM
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| Quote:
He defines "efficiency" as the "ratio between the real speed of the boat and the theoretical speed of the propeller", confounding it with the slip. |
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#8
09-06-2009, 08:08 AM
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| What do you think about this bionic propeller from EveLogics GmbH in Berlin? js
__________________ www.sassdesign.net I'm not lost, I'm just uncertain of my position. I'm still confused, but on a higher level |
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#9
09-06-2009, 02:28 PM
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| looks expensive
__________________ If this is tourist season, why can't we shoot them? |
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