My phantom lags when I first start to fly it. I'll give it full throttle and it seems to struggle then it will get a foot or 2 of ground and then takes off like a rocket and flies normal. I have no attachments not even the go pro mount. I have the dual external battery mounts a new gimbal to add to it when I get my skills down and I am concerned it will have a very hard time taking off after I add the extra weight. Any ideas??????