Graham,
You do indeed have a very large area to map! I assume that you have considered using just an APM plane? Granted, these have their own set of problems like protecting the payload and requiring a landing area, but the efficiency and weight will be better without copter features. Since the area is so large, maybe a roadway exists for temporary landing strip. The FireFLY6 Pro can do up to 243 hectares per flight but it is more expensive. Anyway, I’m just spit-balling here and now understand your needs.
Atico,
I’ll graph my three motor outputs in hover mode and post it to see how much the rear motor is working. I suspect that it works less than the front motors as the triangle is not symmetrical. I’m currently using the 14x5.5 t-prop.
Rafael,
Welcome to our Nimbus VTOL group! My hope is that others like you join in to help form opinions on various issues and solutions. Sometimes this forum can be very quiet!
There are several reasons why your Nimbus oscillated upon return to hover mode. Initially, I would suspect a PID issue or not being pointed into the wind. Did you test the hover mode in various conditions? Do you have the weathervane feature enabled? Can you post your .BIN file from the flight where it oscillated?
Cheers!