When I’m loitering with my plane, I probably only need about 10% throttle, but I found that if I put TRIM_THROTTLE to 10, it will not apply enough throttle to RTL against a heavy wind.
Now I have TRIM_THROTTLE at 35, which seems enough to RTL against a 20kph wind, but when I’m loitering, it’s applying too much throttle and wasting batteries.
Am I doing it wrong and/or is there a way to give minimum throttle needed to maintain flight while having RTL apply more throttle to fly back against heavy wind?
Thanks Andre, this sounds interesting, but I’m not sure if I fully understand how this is supposed to work.
My problem is that I’d like CRUISE at minimal power and LOITER to use minimal airspeed, just enough to keep flying speed.
But when I RTL, I’d like it to indeed have at least a 40kph ground speed.
If I set MIN_GNDSPD_CM, will that impact loiter and minimum speed cruise?
If I’m not mistaken , the value that is set for MIN_GNDSPD_CM is the minimum speed-made-good over the actual ground. So regardless of wind speed or air speed , one my be assured that the craft will actually make progress. I think that it (param) should help to make the loiter more circular with respect to the ground when there is strong wind.
It’s a little more complicated than that. Here’s how it all works:
Set TRIM_THROTTLE to desired cruise speed for Auto and RTL
Set MIN_GNDSPD_CM to the minimum forward ground speed you want. I use 1000 cm, or 10 m/s.
It’s still tricky from here.
Set ARSP_FBW_MAX to the max your airframe can handle. Your Pixhawk gives priority ARSP_FBW_MAX over MIN_GNDSPD_CM to prevent airframe redline. You would need ARSP_FBW_MAX set to 25ms in order to move 10ms ground speed against a 15ms wind.
You can manipulate airspeed while the plane is in AUTO modes if you set Throttle_Nudge to 1. The plane will fly at TRIM_THROTTLE so long as your throttle stick is below 1/2. Max throttle stick will move the airspeed up to ARSP_FBW_MAX.
Oh, sorry, just realized you’re using TRIM_THROTTLE. My post applies to TRIM_ARSPD_CM and assumes you’re using an airspeed sensor. Not sure how you can define different airspeeds with TRIM_THROTTLE only. So to correct the post above:
Set TRIM_ARSPD_CM to desired cruise speed for Auto and RTL
Set MIN_GNDSPD_CM to the minimum forward ground speed you want. I use 1000 cm, or 10 m/s.
It’s still tricky from here.
Set TRIM_ARSPD_CM to the max your airframe can handle. Your Pixhawk gives priority ARSP_FBW_MAX over MIN_GNDSPD_CM to prevent airframe redline. You would need ARSP_FBW_MAX set to 25ms in order to move 10ms ground speed against a 15ms wind.
You can manipulate airspeed while the plane is in AUTO modes if you set Throttle_Nudge to 1. The plane will fly at TRIM_ARSPD_CM so long as your throttle stick is below 1/2. Max throttle stick will move the airspeed up to ARSP_FBW_MAX.