In FS airplanes, it's called a Q tip (Q for quiet?) propeller

Aerodynamic improvements include a reduced diameter and decreased tip speeds. This results in quieter operation and reduced tip vortices. The 90° bend reduces the vortices that, on traditional blades, pick up debris that can contact the blades and cause nicks, gouges and scratches.

Sounds like a marketing ploy to me

http://www.hartzellprop.com/product_...pport_faqs.htm

Cheers!

Jim