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Author Topic: 7 Blade Scimitar props  (Read 1574 times)

essex2visuvesi

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7 Blade Scimitar props
« on: February 07, 2013, 12:57:33 PM »

As some of you are well aware I am in the process of building a Robbe Seawolf.  I made the fatal mistake of looking on propshops website and came across the 7 blade scimitar props which in my opinion look the business and much nicer than the 3 bladed plastic prop as supplied in the kit.
So I have decided I would like to fit one to my seawolf.  My question is this... do I order one the same diameter as the robbe 3 blade or is there some formula to work out the difference?
I'm guessing a 7 blade will draw more current than a 3 but in turn will give more torque.... is this right? or are the pitches different enough as to give the same power output/current draw
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essex2visuvesi

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Subculture

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Re: 7 Blade Scimitar props
« Reply #2 on: February 07, 2013, 09:43:57 PM »

The main three factors which affect how a prop will perform are-

Diameter
Pitch
Blade area.

Secondary factors are blade shape and number of blades. Preferably the fewer blades you can get away with, the better.

That prop gives diameter but not pitch or a pitch ratio (wish Simon would standardize his system, it's very confusing), so it's difficult to give you a ballpark figure for performance, and it would only be a rough estimate at that.

What i can say is that your drive system should be able to deal with it without any difficulty, and you could even consider going to a 2" diameter prop.

essex2visuvesi

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Re: 7 Blade Scimitar props
« Reply #3 on: February 08, 2013, 06:52:11 AM »

Thanks :)
I think I'll start off with the supplied prop for initial testing and then fit the 7 blade
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essex2visuvesi

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Re: 7 Blade Scimitar props
« Reply #4 on: February 08, 2013, 10:00:09 AM »

The main three factors which affect how a prop will perform are-

Diameter
Pitch
Blade area.

Secondary factors are blade shape and number of blades. Preferably the fewer blades you can get away with, the better.

That prop gives diameter but not pitch or a pitch ratio (wish Simon would standardize his system, it's very confusing), so it's difficult to give you a ballpark figure for performance, and it would only be a rough estimate at that.

What i can say is that your drive system should be able to deal with it without any difficulty, and you could even consider going to a 2" diameter prop.


Had a reply from Simon at prop shop and he suggested the MS/22/7/RH/BR.  From what I have read on here and other forums he has a rough idea what he's doing so I'll take his advice
[/size]At 42 quid plus postage I hope he's right! {-)
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hollowhornbear

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Re: 7 Blade Scimitar props
« Reply #5 on: February 08, 2013, 10:24:07 AM »

I have a six blade on mine works well and looks good. dia 2"approx.
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essex2visuvesi

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Re: 7 Blade Scimitar props
« Reply #6 on: February 08, 2013, 06:57:50 PM »

HHB
what motor are you using with that and at what voltage?
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hollowhornbear

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Re: 7 Blade Scimitar props
« Reply #7 on: February 08, 2013, 07:12:36 PM »

kit motor and 7.2 volt nicad 3000 mah.
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