I have a Phantom 1.1.1 with self tightening props. I've been flying it for about 8 months now with 9" CF props, gimbal, GoPro. Made all fine tuning adjustments with gain etc. Real happy with the results. It has sat for the last 10 days due to weather and work commitments, took it out today and when I tried to climb in altitude quickly, I noticed it wanted to corkscrew and seemed to fly erratically. I checked all settings in NAZA software and re-calibrated compass and Tx controls and its still the same. In desperation I put on the OEM 8" props and the issue seemed to disappear. Could it be a motor or ESC issue?