Originally Posted by bobly
Woops -- didn't know we were talking about 3 blade props. Mention was made of the 7x3.5 which I had just picked up at lhs on Friday and it's a two blade, just .2" longer than stock one. Thought that is what the reference was to. I'm not much of a fan of 3 blade props. Maybe I just never found the right one for my applications, but I've never found one that would perform like a two blade. Always heard that two blades were more efficient than three also.
Originally Posted by Airman74
Two blades are ALWAYS more effecient
That's why ducted fans and turbines not as effiecient as two blade :-)
Yes two blades are always more efficient. The reason you'd use more blades is thrust, more blades = more thrust for the same prop disc area. You could of course use a longer two blade prop but you have ground clearance to consider.
I've only had one plane that had a three blade prop work well. But that was a plane with short landing gear that sat really low to the ground.
The other thing to consider it scale appearance. Three blade props just look sweet on an Edge, just like the full scale ones!