Propellers: less blades vs. more blades

[turbidus]

From MT....

Looks like reduced noise is a significant benefit:

World's first 7-bladed Quiet Fan Jet Aircraft Propeller MTV-47 is now supplemental type certified by EASA STC 10014953 R3 on the Pilatus PC-12 powered by a Pratt & Whitney PT6A-() propeller turbine.
The installation of the 7-blade MTV-47 on the Pilatus PC-12 reduces Ground roll distance by approx. 10% and Take-off distance over 50 ft obstacle by approx. 15%. It reduces also the inside and outside noise significant and complies with the strict German Noise regulations.

5 balded prop:

• Applicable Aircraft: Quest Aircraft Design LLC Kodiak 100 Series
• Engines: Pratt & Whitney PT6A-34 Engine

• Best vibration damping characteristics for almost vibration free propeller operations!
• Bonded on nickel alloy leading edge for superior erosion protection of the blades!
• Take-Off improvement by 20%!
• No propeller speed restrictions on ground while operating in low idle!
• Unlimited blade life and FOD repairable blades!
• More ground clearance = less FODs!
• Lower ITTs during start-up for less engine wear!
• Unbeatable esthetic ramp appeal!
• Significant cabin noise [up to 5 dB(A)]and vibration reduction!
• Comply with the strict German noise regulations 2010 - „Landeplatz Lärmschutz Verordnung“ for unrestricted airport operation in Germany and other European Countries!
• Max. RPM reduction to 2000 RPM with increased torque for 750 shp!