Differential blade design for propeller noise reduction

A propeller comprising:

• a hub;
• a first blade group having at least one first propeller blade;
• and
• a second blade group having at least one second propeller blade, each of the first propeller blades being substantially identical and each of the second propeller blades being substantially identical, the at least one first propeller blade and the at least one second propeller blade being mounted to and equidistantly spaced about the hub, wherein the at least one first propeller blade of the first blade group is configured to generate noise at a first noise signature and the at least one second propeller blade of the second blade group is configured to generate noise at a second noise signature, the first noise signature and the second noise signature being different from one another.