What Prop to use

by Eddie Postell in 2 Stroke Technical Questions 12 years ago

I have the Rans S4 Coyote with the Rotax 503 single carb with "B" gearbox. The more I read about props and what I need, and the phones call has got me confused. I get different answers. Who is right? Some says 2 blade , others say 3 blade. All gives different size and lengths.

Re: What Prop to use

by bill martin » 12 years ago

bill martin

10 757 0

Eddie,

I have a friend with an S4, same engine, and he uses a three blade adjustable Ivoprop. Powerfin also makes a nice adjustable composite prop. If you give either of them a call, they can suggest the right prop for you. Two or three blade props will both perform well. You just have to dial in a little more pitch with two blades. With Powerfin, you have to adjust each blade individually for perfect pitch angle. (which I prefer). The Ivo changes pitch on all the blades at once by turning one screw.

With a two cycle engine, I prefer an adjustable prop rather than a fixed pitch. Two cycles are very sensitive to weather changes and the ability to change the pitch with the weather gives you the ability to squeeze all the horsepower out in every season.

Those two props are the two I'm most familiar with but I'm sure there are others out there just as good.

Blade length can be pretty much whatever you prefer. Longer length means more mass inertia (bad thing) but less pitch (good thing). Just so you're not mowing grass every time you take off. With three blades, you can have shorter blades for plenty of clearance and still have lots of thrust.

Any of the prop guys can tell you what they have been selling other people with Coyotes.

Bill.

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