Bar Cut Prop Questions

[Eric Perez]

I'm spinning a Texas cut Prather S215 on my current cat project. I'm looking into getting the engine to a higher RPM range -see what the effects are.

I don't think that pipe tricks are going to work too well so I'm looking at what prop mods that can be done.

I've got (2) Octura X438 to work with, one is texas cut

Also in my inventory are some Prather S215. It's easy to get Prather Props in my area so it seems to make sense to start the prop mods with them as they are easily replaced :

I've used the texas cut where you round out the tips of the blades closest to the nut (back of boat) therby reducing the diameter slightly with good results.

What is the next step in diameter reuduction or "apparent" diamter reduction without hacking off the entire profile of the blade?

Latelly I've been seeing some bar-cut props at the local pond. What is the effect of cutting a notch on the inside portion of the rear blade?

Keep in mind that we are talking about a cat hull.

Thanks

 

[Jerry Dunlap]

Re: Notching the trailing edge of the propeller

This would reduce the blade area with the idea of "unloading" the prop in hopes of increasing RPMs and top speed. At least, that's my take on "The Notch."

Jerry D.

 

[TimD]

Back cutting the prop can be very effective if the prop is loading up the engine. Get yourself some tooling dye, paint it on to the blades of the prop, let it dry then take the boat out for a run. after a run you will see which parts of the prop are less effective because there will still be a lot of dye on those areas. Those are the parts you want to remove to unload the prop more.