Check with the Experimental Aircraft Assn. There have been scimitar shaped props that tend to automatically adjust to airspeed and load.
The Aeromatic props of the 1940s and beyond have angled blades and counterweights that adjust blade angle automatically. The concept is great, but the wood blades in use at the time were clubs for airfoils. Planes like the Bellanca Cruisair with a large differential between cruise and landing speeds gained the most benefit from them.
GB
former owner of 1946 Bellanca Cruisair with Hi-Cruise Aeromatic prop.