ORIGINAL: Jetison
Would a four bladed prop give more thrust than a two or three bladed prop?
Not without a larger engine to spin it...
The Reader's digest of the whole thread is that the less the number of blades the more efficient the prop is. The only reason we have other types is for various reasons why the engines can't use two blade props due to size and tip Mach speeds and such.
Any given engine will produce more thrust with a two blade prop than a multi bladed prop assuming the prop is sized to allow the engine to achieve the same peak power output. The same applies to electric motors. If the props draw the same current, and therefore the system is using the same number of watts, then the 2 bladed prop will be more efficient than a multiblade prop. The more blades the worse the thrust.