Throttle lowers when i switch to FWBA mode

ArduPlane Plane 3.7
1

Hi there, whenever I switch mode from manual to fwba my throttle lowers. I’m running 3.8 but couldn’t find a forum for that, but it happened on 3.7 anyway. The issue is, if I try to take off in fwba, I really need full throttle, but its about 10-20% less than in manual mode. THR_MAX is already set to 100 so it isn’t that.
I’m using a pixhawk ap.
Can anyone help ?

2

I had a similar issue and THR_MAX was the culprit then (it was set to the default of 75).

The other possible culprit could be incorrect radio calibration and params.
can you please check that the RC CH3(throttle channel) output is the same for both modes -FBWA and manual. I had noticed that in FBWA, the RC CH3 out stopped following RC CH3 input after a point.

Is your SERVO3_MAX (or RC3_MAX in 3.7 and lower) parameter set such that you do get 100% throttle, and not lower?

3

Thanks Nihal - I will check that this evening and report back.

4

Hi Nihal,

Yes just checked - SERVO3_MAX is set correctly.
If I switch to FWBA from manual anywhere during the throttle range, I get a 10-20% reduction in prop speed, right from low throttle all the way to top end

5

hmm, does the throttle cut-off at low input?( when throttle is low, about 10% and you switch to FBWA, does it reduce all the way down to zero throttle?)

The next thing I’d confirm is if your RC3_MIN value and SERVO3_MINis also set in the right range, are they starting at the same value? also check if the RC3_OUT is the same as RC3_IN in both modes. It’ll be lower in FBWA mode for all throttle values if the SERVO3_MIN is lower than RC3_MIN.

1 Like
6

Thanks very much I found it now - I followed ur advice and then I changed the setting for RC3_DZ and it works perfectly now at all throttles !!

Cheers Nihal