Abc prop characteristic

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Roxyflash

Well-Known Member
Joined
Aug 20, 2003
Messages
1,490
Need to get a few more props not sure which ones are low lift pusher style props or lifting style props.I do know the chopper ones work well on monos.I need to get some for a f41 cat and some for a slingshot rigger.My question is how does the rake and bar numbers work?
 
BAR is the blade area of the prop. The higher the bar, the bigger the blade area. ABC has props that vary from .38bar to .75bar and 10* rake to 23* rake.
 
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If you stand a prop that is 3" diameter in the center of a 3" circle and look straight down at the prop, the .38 props blades will be covering 38% of the circle. .50 covers 50%, a .75 three blade will be covering 75%, ect., ect. If you look at these photos I took, you will see what I'm talking about.
 

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If you stand a prop that is 3" diameter in the center of a 3" circle and look straight down at the prop, the .38 props blades will be covering 38% of the circle. .50 covers 50%, a .75 three blade will be covering 75%, ect., ect. If you look at these photos I took, you will see what I'm talking about.
Cool, something new for me. I knew what the numbers ment to me. But now I know how the number is derived.
Thanks
Mike
 
The higher the degree of rake the lower the lift. ""Most of the time!"" NOT always the rule. For instance a 2717/2 19* .38 will have less lift than a 2717/3 23* .47 prop. You think how dose a 19 degree rake prop have less lift than a 23 degree rake???? It has to do with the amount of factory cup that is in the face of the blades. If you have both of those props in your hands and you run your finger down the face of the blade on both of them, you will feel more cup in the 19 degree prop. The 23 degree prop will feel a lot flatter starting in the middle of the blade and out to the tip. That flatter blade dose not concentrate the water cone coming off the blade as much and that causes more lift. But like I say most of the time it is just in the rake that will give the prop more or less lift. Hope this helps you.
 
Bob,

Don’t you think the three blade will have more lift because
one blade is always in the water?

Thanks,

Mark
 
I appreciate the help just trying to figure out some props for my new builds.What props do the f41 cats like if you have any experience with them.
 
I raced a F-41 for years and my "go to" prop is a 2914/2 15* .50 prop with a couple mods done to it. The only time I would not run it is when it gets very hot and the air turns to crap. Then my 260 had a hard time turning it.
 
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I have the cmb 27 in mine any recommendations
 

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