Motors cost nothing a few pounds for a set of 4 . If u crashed it u more than likely damaged the motors or control board. Check all the solder points are ok and no wires are detached. If thats ok and the motors rev up and respond to transmitter power then the board is naf. U can bypass the power control by placing a small blob of solder on the board in the right place. This bypasses the gyros and enables normal flight again. The gyros perm set at default so no need for calibration. Email me if u want to know where and ill send u photos stormx29@googlemail.com