I recently purchased a Bladerunner RC Helicopter. When I flew it, it would rotate counter clockwise (nose left). Even when I pushed right on the remote control it still when counter clockwise. I took of the fragile outer shell (the shell only weighed down the helicopter) and a small gear fell out. I put it back in. The Bladerunner has two main rotors and a rear rotor facing upward. Can anyone give me some advice. Any advice would be appreciated greatly.

With 2 main rotorblades, they need to turn at same speed and same angle of attack
To not spin. The gear is probably not extra. 2 other methods to keep Chopper from spinning(Counter the Torque), is 2 counter rotating blades(one on top of the other), another, is small tail rotor to counter torque.