Replace a main rotor on a Mini Helicopter with this useful guide. Manufacturers of remote controlled mini helicopters build the helicopters with durability in mind, enabling use of the helicopters by flyers of all ages. No matter how durable the helicopter may be, however, mishaps will occur. Over time, damage may occur to the main rotor of the helicopter, bending it out of shape or breaking it entirely. When this happens, you can replace the damaged rotor with a new one, making the helicopter useful again.
Hold the rotor shaft securely beneath the rotor blade with a pair of needle nosed pliers.
Pull the rotor blade upwards, twisting it around the shaft as you lift it from the helicopter. Use a hobby knife to cut away the plastic blade if it will not move by twisting off. Cut along the side of the rotor blade against the metal shaft until you reach the metal. Twist the cut rotor blade from the shaft to remove.
Push the new rotor blade onto the rotor shaft, sliding the hole in the center of the rotor blade over the metal shaft while holding the shaft steady with the pliers. Press down on the rotor until the end of the shaft is level with the top of the rotor blade hole.
Release the shaft with the pliers and test the rotor blade by turning it in place. Examine the shaft during the test to make sure the shaft turns along with the turning blade and that the blade is not turning around the stationary shaft. If the rotor is loose and turns around the shaft, remove the rotor and place a small amount of CA glue on the top of the shaft. Replace the rotor and wait for the glue to dry according to the drying times recommended by the glue manufacturer. Repeat the test on the glued-on rotor blade.