Hi all,
After alway's flying manual(20 years) i wanted to help a farmer to do some arial mapping. I have build a Skywaker 1900 flying nice and trimmed manual and also easy to fly in assisted flight.
In auto (grid) mission it does not follow each path correct and also skipping waypoints, i did already a auto tune on the plane. after that i created a automission with a box and tune the L1 parameter back from 20 to 16 (15 did not get any more accuracy). Changed also the max banking angle from the std 45 to 50, it can do nice corners but for some reason it does not follow the flight path correctly and even worse skipping waypoints
I use a PixHawk 2.1 with the Here+ gps. using Adruplane 3.8.4 and mission planner 1.3.56. All digital servo's running on 4s. GPS signal is excellent, i am out of ideas what to check next.
I have set overshoot to 80 meter and leadin to 20 meters to help the plane to get on track on time but it does terrible job at it. Way-point radius is set to 10 meters. See attached screenshot
I am not speaking natural English, if something is unclear please ask.
Replies
I maiden the plane with just a Receiver the traditional way after build and did trim it using the linkages to get it fly correct on normal cruse speed , so without any kind of controller. And also with Pixhawk in manual mode. But i will check the logs to be sure.I hope I overlooked something
iskess said:
How do you know that you don’t need rudder? The plane will fly in a straight line of the ailerons are compensating for the rudder. Check the lateral acceleration in the logs to be sure.
Bert said:
Hi,
Thanks for your suggestions
At cruse speed ( in manual mode) i don't have to add any rudder for compensating only at full power, in auto mode i fly at 12 m/s not even half power.
I will decrease L1 even more and increase the bank limit to 60. Not sure if i have time this week ( work & weather) but i will try those and report my findings here.
I’ve seen this before, especially with the Skywalker. I suspect that your plane is flying in a slip due to the spiraling slipstream from the big pusher prop hitting the tail and creating a yaw. You can see the plane flying in a slip (crooked) while it’s climbing out just after launch. Try adding lots of rudder trim and see if that helps the tracking accuracy.
Additionally I think your L1 is still too high. Keep decreasing it until the plane starts oscillating across the path, then increase. I use 60 deg bank limit to keep the turns tight. The 1900 won’t tip stall easily. The 1880 is terrible that way.
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