Ardupilot will always allows bank angle up to 25 degrees in order to ensure enough maneuverability.
Is there ways to further reduce this limit? Say 20 degrees for example.
I am working with a 35 MTOW experimental quadplane VTOL, mounted with a huge flat payload over the fuselage. This design is sensible to side winds and the payload’s shape is destabilizing in turns. That’s why I’d like to limit the bank angle.
I can tolerate larger turning radios.
I am trying to explore parameters, however no matter the case, it seens that the airplane always starts the turn with 25 degrees bank angle.
Is the problem with the bank angle or with lateral (sideway) forces? An aircraft in coordinated flight shouldn’t experience lateral forces even at extreme bank angles.
I don’t know enough to help you with your original question but it might help others to know if your concern is about lateral forces or not.
Please note STALL_PREVENTION parameter is set to 1, meaning:
“when in roll controlled modes the autopilot will monitor your demanded bank angle and airspeed and work out if you have sufficient margin above the stall speed to turn at the demanded bank angle. If you don’t then the turn will be limited to the safe limit, but it will always allow a bank of at least 25 degrees (to ensure you can still manoeuvre if your airspeed estimate is badly off)”
From my understanding, STALL_PREVENTION will override ROLL_LIMIT_DEG under 25 degrees.
I will try to collect some flight data for the subject.
Might be worth testing in SITL first. I suspect you’ll find it’s limited by the lesser of the two values. The majority of planes would have the roll limits above 25 degrees so you’re working an edge case.
Heads up that you might also need to tune NAVL1_LIM_BANK if you’re using loiter turns on station and the radius isn’t what you’ve expected. A 20 degree max bank on that big of a plane is going to need a lot of room.