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  #31  
Old 04-26-2012, 05:13 PM
TRBenj TRBenj is offline
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Eric, the stainless prop pictured above is a 14x16 (Im sure thats what you meant), and I can definitely see the resemblance to the older 3-blade legend design. Your 12" 3-blades still work great on the smaller, lighter vintage CC's. No idea how old this one is, but the shape is pretty much the same.

I can see how thinner blades would make a prop faster (more efficient). I cant say Ive ever noticed any fatigue on any of my CNC props, but I guess we'll see how they stand up to the test of time! Luckily I dont run in a river or lake with any real debris concerns.

I cant say I agree with you on the last few hundred rpm's not adding any speed. I think I understand what youre saying though. The more wetted surface a hull has, the more RPM it takes to push it faster- especially at the high end... so youre getting less speed per extra rpm at the top than you do in the midrange. Still, to say that the last 300-400 rpm can return next to no measurable speed increase seems to be a real stretch. That has not been my experience with the brand X props.

I do realize that there are several parameters that are different in the 2 prop designs, which are not easily measured or communicated I dont have a understanding of how pitch distribution will affect performance, but I do recognize that aft rake will help top end speed by lifting the bow slightly. Whether or not the Acme design is a "work boat type prop" really doesnt matter much to me, I just want the best performance out of my non-100mph ski boats.
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  #32  
Old 04-26-2012, 05:24 PM
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EJ OJPROP EJ OJPROP is offline
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Was just speaking of the blade shape being of that type on their prop, not a knock at all. This prop is the older style for sure, changes were made on the Legend line.

I'm saying there is a point where the RPM will run away from the MPH, with an Acme or an OJ. I know you have run many props over the years as have I, but there is a wall they all hit. It may not be as deep as 300 RPM but there is a point.

You are correct about rake, number of blades will affect lift as well. Bow lift does allow for a little more MPH but will also increase the size of the wake. I guess we try and make the wake as nominal as possible with our props, for the slalom guys. The boarding props are a different animal all together, some of the rake and pitch distribution has changed on our designs for those props.
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  #33  
Old 04-26-2012, 05:36 PM
TRBenj TRBenj is offline
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Agreed on there being a wall... but I prefer it when Im hull limited as opposed to prop limited. That point comes too soon as it is!

You mention props for slalom guys (I totally understand the rationale, by the way) and the wakeboard guys. What about the barefoot guys?
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  #34  
Old 04-26-2012, 05:37 PM
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Barefoot guys get the thin ones!
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  #35  
Old 04-27-2012, 01:10 AM
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Eric.


What does a sharp leading edge do to the top end kind of like a cleaver style prop. I've seen race boats with extremely sharp props. Why do we see blunt edges on our props. Either way of a sharp prop or blunt prop was to run someone over they both would cause serious damage to what they chop up. I am just curious and was wanting to learn something.
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