I've picked up a second hand P4A ... It doesn't fly that well and constantly seems to drift of to the right...I've been mucking about with settings and have made it worse ...how do I reset all the gain and sensitivity and cotroller settings back to default?

Hi there, our apologies for the inconvenience. I would recommend you to  reset  the settings by going to MC settings- Advanced settings and look for Reset Gain and Expo Tuning. You can also do IMU calibration by following the video tutorial below. Thanks for your support.

Will a mis-set IMU calibration cause it to flr 'not straight'

Personally, factory reset then:

1 Check every single piece of software is up to date (PC/Mac, Phone/IPad/Tablet, Remote and Drone) - if not, then update.

2 Calibrate/test everything you can from the remote through to the drone(compass, IMU, gimbal, remote etc).

In theory then you know the machine is clean and up to date and you have physically checked and tested everything, before then having a play and hopefully any issues have gone away.

Trampintransit Posted at 11-6 06:12
Will a mis-set IMU calibration cause it to flr 'not straight'

Hi there, yes,It is possible. If the drone is not flying staight, please follow the instructions below.
1. Calibrate the compass in a place with no interference.
2. Calibrate the IMU.
3. Calibrate Vision Systems.

You can check the components of the IMU below. Please let me know if you have other concern, we're here to help. Thanks for your support.
Gyroscope: Keeps the aircraft steady.
Accelerometer: Measures acceleration.
Barometer : Measures Altitude .
Thermometer : Measures temperature .