This question is based on a conversation I had with a buddy.

If I’m understanding things correctly (based on what I’ve read on this thread), a two bladed prop is more efficient than a three, four, or five bladed prop due to the second, etc blade being within the ‘dirty’ air of the fist blade.

If the above is true, why do aircraft such as the C-130 use four bladed props? Do they produce more power, speed, etc, and if so, how? Also, if this is so, what determines ‘efficiency’?

(I was under the impression the main reason to switch to a prop with more blades is to raise ground clearance.)

Could my confusion be caused by mixing fixed pitch props with variable pitch props? Could it be because of the difference between models and actual aircraft? Does this difference in props become a factor?

Any help would be greatly appreciated.

My knowledge (or lack therof), is solely from this thread…extensive reading. I will be either signing up for a college physics and aerodynamic course, or obtaining the college books for those classes to lessen my ignorance, and further my understanding and knowledge.

Thanks again.