everyone talks about pitch but what about diameter.....

[metalmessiah]

what effect does a change in prop diameter have on choosing the right prop? is there a rule <br />of thumb like the 1" pitch equals 200 rpm for judging diameter? I ask all this because of advice <br />I am getting from local shops. I decided to switch from aluminum to stainless & started shopping<br />around. Everyone I have talked to said to go from the 12 1/2 diameter I am running now to a <br />13 1/3 diameter. All said to run the same pitch except for one place that said to drop 1" in pitch.<br />Anyone feel like a tutorial on how diameter affects your performance?

 

[JB]

Re: everyone talks about pitch but what about diameter.....

Howdy, MM.<br /><br />This may help, it may not. But at least it will bump your post.<br /><br />Larger blades get more "bite" and offer more drag. A bigger diameter prop will give a better hole shot and slightly lower WOT rpm and speed. A 4 blade prop will do about the same.<br /><br />Good luck.

 

[Spidybot]

Re: everyone talks about pitch but what about diameter.....

The larger dia results in a higher blade tip speed (too high to produce thrust) which has negative effect on hi-speed setups.<br /><br />If you like you can read more in this <br />previous post

 

[Dhadley]

Re: everyone talks about pitch but what about diameter.....

With a larger diameter you can increase the X dimension to reduce gearcase drag and therefore gain speed. <br /><br />At the same X dimension, yes you may lose some top rpm and speed with more blade area. <br /><br />Take advantage of the increased technolog and fine tune your set up for the increased blade area. You won't regret it.<br /><br />Good luck!