Elevon Output Range Limited

I have tried and tried to get elevons working on my new pixhawk mini (3 days). I have read all of the documentation but no joy no matter what. Why did they have to fix something that wasn’t broke?? Can I load an earlier version of plane on my f.c? if so, how?

Hey Larry,

to answer your question, you can load previous firmware versions using MissionPlanner’s “previous firmware” option under “initial setup” -> “install firmware”.
That being said, I’d strongly suggest to not downgrade because of the issues you’re having! recent firmware versions have added an enormous amount of overall convenience, ease and functionality. it just requires a certain amount of adapting to the separated RCInput and SERVO output handling. i’d suggest to first set your SERVOn settings straight without looking at what your RC input does, and THEN adjust your RC settings accordingly.
make sure there’s no mixers active in your transmitter. just one plain channel each for ail and ele. double check your FC is oriented correctly to your airframe’s axis.

in short terms you want to
1.: choose two FC servo outputs to connect your elevon servos to
2.: set the respective SERVOn_FUNCTIONs to 77 and 78 accordingly (elevon left / right)
3.: set the respective SERVOn_REVERSED accordingly to have your control surfaces react correctly when pitching and rolling your airframe in FBWA mode: both elevons need to go up when you pitch nose down. if you roll your plane right (left wing up), the left elevon has to go up, the right one down.
4.: now set your RCInput reversals on your ail and ele channel accordingly to provide correct movements in manual AND assisted modes. you can either use ardupilot’s RCn_REVERSED option OR set the reversals in your transmitter.

cheers, basti.

A little frustrated by the sounds of it.
Can you describe the specific problem you are having?
The community here are pretty helpful :slight_smile:

Well, I no longer have the option to load different firmware, i’m using 3.9 btw. But it does its own thing and no where can I downgrade or change the firmware. I’ve tried all of the steps listed 77, 78 and also 4 and 19 as servo function.Very confusing! I’ve tried reversing elevator, aileron etc. I’ve made sure that I do not have elevon mixing engaged in my transmitter but I don’t know how to engage it in software. I have tried hooking up my servos directly to my radio channels 1 and two, to make sure that they are going in the right direction but when I hook it up to my f.c. I just can’t get it to work right. The closest that I can get still isn’t right. My elevator and pitch controls are backwards. When I push right or left on my joystick control the elevators move,(both servos move up and down. When I push the control forward or down then the servos move opposite of each other. I’m fairly new to rc planes and after using apm 2.8 with firmware 3.1? this has really been a disgusting experience, I hate it. I wish I had just bought apm pro or apm 3.1. So difficult for me to explain and understand over internet. I really miss my Parrot Disco.

Well, I finally got my servos to respond correctly. however, they move very little, especially the elevator. Maybe 1/4" up and down. I made sure that my endpoints are at 100% in my transmitter, no expo but still the same. Any suggestions?

Sorry that you’re having a difficult time. I’ll try to help.

Do you know how to export a “.param” file from Mission Planner? That will let me see the configuration of your flight controller. (a pixhawk mini, right?)

It sounds like you have your elevators and rudders “doing the right thing”… did you use this page of the documentation? http://ardupilot.org/plane/docs/servo-functions.html

Thanks for your help hunt0r, I adjusted the Lim settings in Mission Planner and finally have proper movement on all controls and servos!


@greystone, will you please explain your confusion and what solved your problem? I’m not quite sure what Lim settings you are talking about. Maybe our documentation could have pointed you in a better direction. We could use your feedback.

1 Like