How to get flaperons to work correctly?

Hi all,
I’m having trouble getting flaperons to work correctly, and hope that somebody can help me.

Firmware: ArduPlane 2.76
Board: Arduflyer 2.5.2
Radio TX: Turnigy 9XR
Radio RX: FrSky DR4-II set to 8ch PPM.

I’ve set a mix in Radio TX to add 20% to Ch 1 and Ch 5 when flap switch is toggled on.

I have two aileron servos.
Starboard servo connected to APM output 1.
Port servo connected to APM output 5
RC_5_FUNCTION set to 5 (Flaperons)
Setup like this the Port servo does not move with aileron input in any flightmode.
It is also not responding to attitude changes in any of the auto modes. (Loiter, Auto, Cruise)

If I change RC_5_FUNCTION to 18 (Aileron With Input), the Port servo respond aileron-wise as expected in Manual, Stab and FBWA, but in Stab and FBWA it seems that Radio input 5 is ignored.

The result of this is that the flaperons function as intended in Manual mode, but in FBWA and Stab the flaperon function on the Port servo is reversed causing the ailerons to be set for a roll.

Log-files and, hopefully, a video will be posted tomorrow.

[mf]Plane/Flight Modes, Radio Configuration, and Failsafes[/mf]

That has been a bug for a long time. I tried it over a year ago with an older version and it always gave me a hard roll when I put the flaps down.


I couldn’t find anything regarding this in the issues list?
Bad search by me perhaps?
I’d be happy to add one, but I don’t want to be redundant.

Anyway, as a work-around, I used a V-tail mixer, which seems to do the job in all flight modes in a bench test.
It’s not a very elegant solution, and I’d prefer having it as a function in ArduPlane.

Add one anyway, this has been a problem for a long time. Flaperon and spoileron functions need to be fixed/added.

I’m unable to create log-files and video due to ongoing build.
I can create dataflash-logs at a later time if it can be useful.

For now, I’m posting an issue on github.

Using a hw mixer and connecting one side to a pass-thru RC channel is really the only way to get flaperons right now.
You are absolutely right that we should support flaperons in software, and I do plan on adding that, I just haven’t done it yet, sorry!
Cheers, Tridge

This is now working in APM:Plane 3.xx and documented here: … pilot.html