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Old 07 February 2006, 15:36   #1
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Propellors and all that jazz...

OK anyone got a useful and easily understood explanation as to how propellors work? Have heard a few slightly differing theories (might have been the fact the theorists were sinking Guinnesses at the time!!! )

many thanks

missus technophobe
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Old 07 February 2006, 15:44   #2
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they rotate and suck you forward
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OK anyone got a useful and easily understood explanation as to how propellors work? Have heard a few slightly differing theories (might have been the fact the theorists were sinking Guinnesses at the time!!! )

many thanks

missus technophobe
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Old 07 February 2006, 15:48   #3
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Cheers Chris!


I shall relay that to the peeps in question!

Any other offerings?

missus
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Old 07 February 2006, 15:54   #4
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they rotate and suck you forward
surely that's thrusts you forward
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Old 07 February 2006, 15:54   #5
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some will say they rotate and push you forward

so basically the question will be whether they suck or push/blow

a propellor in free air uses lift created by the aerofoil shape of the "propellor wing shape" as a force that pulls the propellor forwards.

in a gasturbine engine there is a misture of suck and blow with the blow being much more powerful due to the controlled explosion that has occured in the engine.

however in a propellor in the water there is no such explosion creating that effect

as usual it will be interesting to see folks views on what actually happens

in air i know exactly what happens, was my job, but in hydrodynamics i am not sure if the same principals apply
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Old 07 February 2006, 16:08   #6
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Quote:
Originally Posted by Hugh Jardon
some will say they rotate and push you forward

so basically the question will be whether they suck or push/blow

a propellor in free air uses lift created by the aerofoil shape of the "propellor wing shape" as a force that pulls the propellor forwards.

in a gasturbine engine there is a misture of suck and blow with the blow being much more powerful due to the controlled explosion that has occured in the engine.

however in a propellor in the water there is no such explosion creating that effect

as usual it will be interesting to see folks views on what actually happens

in air i know exactly what happens, was my job, but in hydrodynamics i am not sure if the same principals apply
No,lost me on the first line!!
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Old 07 February 2006, 16:14   #7
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Hugh
By the way,the cutting of the transducer lead seems to have worked,or lets say it appears to be,I haven't tried it on the water yet
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Old 07 February 2006, 16:19   #8
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missus technophobe
She has done it again, looked what happened when she asked how a jet worked

Pete

Props for girls


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Old 07 February 2006, 16:34   #9
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oh haha, hope it will be all ok for you


i have cut the mushroom off of my garmin

well cut the bnc connector off rather than mucking around making much larger holes in the aframe. but is only coax so will be fine putting back together
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Hugh
By the way,the cutting of the transducer lead seems to have worked,or lets say it appears to be,I haven't tried it on the water yet
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Old 07 February 2006, 16:40   #10
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I think props push the water away from the boat, the boat then moves because of the equal and opposite force generated, hence the need for a thrust washer.

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