My second Vortex 285. First one flew just perfect right out of the box and OSD setup. Finally crashed beyond repair afte two years of probably a hundred flights.
The new one just purchased, wouldn't change flight modes and after hours of OSD adjustments, I finally got it to fly and change flight modes. it flies very well but:
On takeoff, it just hops up and down. I can give it any throttle position from idle to full and it just takes a hop and plops down. After perhaps a minute of this activity it will take off suddenly and fly just perfect for a half minute or minute. But suddenly it will plop down and go through this hopping routine until it suddenly takes off and flies perfect for a brief period and then plops down and starts the routine over again.
I'm flying it with a 2200 3 cell 50C batteries. Spektrum DX9, Lemon receiver. I downloaded the Spektrum file from the internet for flight setup. The endpoints on Throttle, aileron, elevator, rudder is at 147 both + and -. Same setup I used for the original Vortex 285. I've tried the contact email to ImmergenceRC and of course no reply. My local hobby shop attempted to help me out but he could only suggest recalibration of the Accelerometer. That diddn't help.
API Ver 1.31 .

I attempted to link the Vortex with Cleanflight and Beta flight but was not successful. I'm really computer challenged and hope that there is a suggestion I can try that only involves the OSD tuning.