Effects of prop diameter?

[Josh in Pa]

I have a 13-3/4x21 michigan match in stainless steel. I am looking for a new prop for my 350 mag with alpha 1. My current WOT is 4400, at gps of 54. I haven't seen this particular prop for sale, but others like it are 14" or 14-1/4" in diameter. Will this lower my WOT? What stainless props should I consider? I would like to buy a decent prop. I see michigan, stiletto, and some others offer pretty reasonable stainless props. Any advice? Is it true that some places will let you try a prop? Even the less expensive ones? Thanks for any ideas,
Josh

 

[lrdchaos]

Re: Effects of prop diameter?

Your gonna need to drop pitch if you run a larger diameter prop....I ran into the same situation. I would try a 19 pitch in whatever prop you wanna run, get those rpm's up aournd the 48-5000 range.

 

[Silvertip]

Re: Effects of prop diameter?

Prop diameter is a function of prop design. If you compare different pitches in props of the same model from the same manufacturer you will see that as pitch goes up, diamteter comes down a bit and vice versa. So you cannot compare a 13-1/4 x 19 Vortex to a 14-1/4 x 19 Stilleto for example. They are simply different designs. Generally however, diameter will not affect RPM or performance nearly as much as pitch. When you change from aluminum to stainless, change the number of blades, change prop manufacturers, and prop models, you introduce so many variables it's hard to tell what you will end up with. Yes -- some better prop shops will allow you test a prop but then be a sport and buy from them because they likely saved you a bunch of money because you bought the right prop the first time. Even iBoats has a prop exchange program for certain models.