As mentioned above, more prop blades mean greater engine/aerodynamic efficiency. Apart from the Fokker 50 you refer to (Skywest
I guess) compared to the 4-bladed RR
Dart-powered F27, there are other examples; the 500/600-series ATRs also have 6-blade composite props, as do the Dash8Q400, Saab 2000, ATP, CASA-295 and C-130J. Some, such as Airbus A400M and the latest E-2C/D
Hawkeye even have 8-bladed props.
These blades are typically composite material (for weight, corrosion and durability advantages) and sabre-shaped, i.e. curved for better tip efficiency.
Increasing the blade chord was tried some time ago. Check out the earlier marks of
Hercules (C-130B, E, H) and the Lockheed
Electra/Orion. Not as efficient a design as the 6- or 8-bladed prop.
Cheers
