Propeller Theory

[retiredfornow]

I was told by a couple of "shade-trees" around here that if you go from a 3 bladed prop to a 4 blade, you should drop the pitch by 2. Example: 3 blade 13x15 pitch to a 4 blade 13x13 pitch. Does it take more power (torque) to turn the 3 blade or the 4 blade? Or is all that irrelevant? Just trying to learn something. Thanks.

 

[hidef]

Re: Propeller Theory

Most guides I have read say to decrease pitch by 1 when going to four blades from three. It is because the 4 blade prop will slip less than a three blade. Same thing when going from aluminum to stainless use 2inches less pitch because the stainless props have more cup which helps to prevent the prop from slipping.

 

[retiredfornow]

Re: Propeller Theory

Thanks for the info.