Things You'll Need
Instructions
Examine your Havoc Heli to determine what repairs are needed. If the tail rotor is damaged, you can remove it with the rotor tool included with the Heli and replace it with one of the extra rotors also included. Damage to the main rotor is difficult to repair. You might be able to fix a broken blade with glue, but most likely you'll just have to buy a new Havoc.
Open the Heli body, if you can see no external damage. Use a utility knife to carefully cut along the seam that runs along the top and bottom of the fuselage, and pull the copter into two separate halves. Only cut deep enough to get through the styrofoam shell: if you cut too deep, you may cause greater damage to the interior.
Look at the parts inside the Havoc and try to determine what is causing the problem. You may have to replace the battery or motor. If the drive gear is damaged, you'll have to get a new one: you can find small gears at hobby shops. Use a needle-nose pliers to remove the damaged part and install a replacement. Glue the two halves of the copter together and allow to dry.