WPNAV_SPEED=1000 result in 2m/s

Updates my copter from 3.5 to 4.0.3 and now I have some issues with Mission Speed.
WPNAV_SPEED is set to 1000, SPEED_DN and _UP is set to 150.
WPNAV_LOIT_SPEED is 1000, too and RTL_SPEED is set to 0 (will change this parm later this day but I don’t used RTL during my testflight).

If I set a mission, straight line 200m in one direction, the copter fly only with 2m/s exactly in AUTO. In LOITER it will fly with 10m/s as expected. I tried the DO_SET_SPEED with different parms, no change.

Setting WPNAV_SPEED to 500 = copter reached 5m/s.
Setting WPNAV_SPEED to 1010 = copter reached around 9m/s (maybe the mision was to short to get the full 10m/s)
Setting WPNAV_SPEED back to 1000 = copter reached 2m/s

My battery runned out so I had to stop testing this morning…

Maybe a full parameter reset is a good idea?
Thank you.

I am exactly in same situation, always at 2m/s since i updated from 3.6.x ti 4.0.3.
do_change_speed commands do nothing. In loiter it flies fine at set speed, in auto and rtl there is no way of having it go any faster than 2m/s.
Did you solve your issue?

First of all, try it with 4.0.4 there were some significant changes in set_speed handling after 4.0.3

I was wrong on my previous post. We are running 4.0.4 already. Sorry for the error.

OK, then could you post an actual params set which shows the problem mentioned above ? A flight log would be also appreciated.

Tested now 610 and it works, going back to 600 doesn’t work.

Mission Planner or QGCS ?

MP. But it didn’t work even sending a mavlink message with 600. If i send same command long with 610 it works.

Could you share your param file ? I’ll try to repro it with SITL

Will send it as soon as i will be back in office. I am out for some days for a job.


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I have a similar problem with speed on Arducopter 4.0.5. We fly crop sprayers (own Mavlink ground control) and I´m not able to reach desired speed. Our flight plan is like a low flying photo mission where we typically fly 200 to 500m in one direction, 10 m to one side and return 200 to 500m. Even on longer lines, the copter does not reach its programmed speed. If I program 5m/s he likely flies, 4m/s. In order to reach 5m/s I have to program 6 to 7m/s. RTL speed is OK, Loiter also. Only Auto does not work. Since one of my gesses is acceleration, I turned WPNAV_ACCEL to 200 cm/s/s (started at 110 cm/s/s), no changes. It is strange since setting WPNAV_SPEED to 600 or 700 cm/s I reach my desired 500 cm/s. Any idea what I´m missing? Below a bin file with such a strange behavior.


Thank you