RPM range and performance question....

[Silkstringz]

Lets say my engines max rpm is 5750. My 27 pitch propeller will only turn 5500 rpms at WOT and the holeshot is acceptable. I'm considering having Mark work the propeller to a 26 pitch which would put me at 5700 rpm. What would be the benefit of this? Technically I wouldn't gain any speed, right? I mean mathematically the numbers are a wash. If that's true, would there be any performance differences between the two? I know engines have peak horsepower output at certain ranges, but how does that translate into propeller performance. That's something I've never understood.

[Silkstringz]

Anybody?

[magnumb]

Not sure you wouldn't gain any speed. You may and it might run more efficient and put less strain on the engine.
For me I'd rather it turn 5,750 RPM and then only run it up to 5,500 while cruising.

[Savage]

You may, or may not notice a increase in performance, but it is better for the motor to run at Max RPM while loaded.

[Silkstringz]

Gotcha. I understand the benefits for engine longevity. I'm just wondering if turning more rpms is more beneficial for speed in general propeller physics. If you have two identical propellers (in theory)...one is a lower pitch and one is a higher pitch. Will turning the lower pitch propeller more revolutions per minute further bring out the characteristics of the propeller? For instance, would turning the smaller pitch propeller more rpms create more lift if that's what the propeller was designed to do causing less drag and hence perhaps a faster top speed?

[John Jackson]

Add pitch, don't remove pitch as you loose bite. For a 26, either get a 26 or get a 25 and cup to 26"

[Silkstringz]

Add pitch, don't remove pitch as you loose bite. For a 26, either get a 26 or get a 25 and cup to 26"

Any truth to this at all? Anyone notice higher slip numbers when pitching down verse adding pitch?

[angle iron]

Any truth to this at all? Anyone notice higher slip numbers when pitching down verse adding pitch?

I'm no expert but you better take John Jackson's advice!

[Silkstringz]

I'm no expert but you better take John Jackson's advice!

I always trust, but verify. I'm a scientist and it's what I do. I somewhat understand progressive pitch props. I just have a hard time wrapping my head around why you would have higher slip numbers pitching down. On some hulls, bending a 27 to a 26 with added tip cup would perform better than a stock 27 propeller.