i bought simonk 30A ESC.but it not change the direction of brueshless motor.how i do
Most ESCs for aircraft to not have reverse. The operate from a stop to full speed in one direction.
If it is not the direction you need, you can swap any 2 wires between the motor and the ESC.
You would have to recompile simonk firmware with rc car style reverse enabled and flash to the esc. Search over at rcgroups for flashing instructions and how to identify your ESC and the right firmware.
What are you trying to do exactly?
i want to change the direction of motor when i move joy stick up motor run clock wise and when move down then motor run anti-clock wise