Help! 5 blade propeller?

[jtuttle11]

Hey that's interesting. Seems to make sense. Like American muscle cars vs the cars the young people are driving today. Lower rpm & huge displacement vs very high rpm in a little engine. The big displacement engines - high torque on the driveshaft - would push a heavy muscle car as fast or faster than the light high end European sports cars with high-rev engines.

So high torque engines could spin more blades at a slower speed to get the same thrust.
Another factor was clearance to the deck. Like the Corsair using a four blade prop to keep the diameter smaller.

Exactly, That's why you see so many Turboprops with 5 blade props. The reduction of the engine RPMs creates MASSIVE torque Multiplication at the prop.

 

[CampRobber]

I've seen 5 and 6 blade props for cinewhoops but those max out at like 3".

 

[jtuttle11]

I've seen 5 and 6 blade props for cinewhoops but those max out at like 3".

As you increase the diameter of a prop the torque required to spin it doesn't increase directly but more of a logarithmic fashion or even exponentially. You must also consider good old Newton's Law. The one about the 'Polar Moment of Inertia' The farther a mass is from it's center of rotation the greater the effort it requires to change its speed.