As you may see, the main rotors available now are 2 blades in a set with well balanced. In other words, it is not balanced if one blade is added in other balanced 2 blades. Therefore, it makes almost no sense to buy 2 sets of rotor blades set to use 3 blades out of 4.

Now, JR offers Three Main Rotor Blade Set specially balanced for Multi Rotor Blade Head MB-391 at the same time. They are exclusive for Multi Rotor Blade Head MB-391, not only well balanced but also specially selleted airfoil and weight. Please use this Three Main Rotor Blade Set Only for JR Multi rotor Blade Head MB-391.