Motor shutting down
I have a 1/4 scale Proctor D-VII with a Great Planes Rimfire 50cc motor 80-75-230. The ESC is an Castle Creations Phoenix Ice 2 HV160 50V. The battery packs are 12s, 5000 mah, 45-90C. The radio is a Futaba 7C with the trims set at nuetral and the throttle throw set at 100%. The prop is a 23x8 (mid range recomended) After arming, as the throttle is advanced, the motor's rpm increases normally until about 3/4 throttle then shuts off. When the throttle is shut down there is a beep beep --- beep beep --- beep beep (low voltage indicator). when the throttle is increased the same thing happens again, motor stops at 3/4 throttle. If I disconnect the battery and rearm, I get the same results. A couple times though, the motor didn't stop at 3/4 throttle and gave full power (30 lbs thrust). I even got one succesful flight. I've used three different fully charged/balanced batteries with the same results. I just sent the ESC back to Castle and they said it checks out 100%. Any suggestions are appreciated.