ORIGINAL: Bax
This is not a "bug". What happens is that when you have a mix on, depending upon the mix, the trim on the primary will affect downstream mixes. It's not changing the "offset", but trimming. If you have rudder mixed to aileron, then adding aileron trim will affect rudder. If you use the pmixes, you can select in some of them whether the trim will affect the mixed-in channel. In some of the pre-made mixes, this feature may be on or off.
This isn't changed in the Super version.
We're sorry for the delay in response. This wound up on the second page and got lost for a bit.
Well, I bought a 9C Super and I don't agree with your assessment that this behaviour is not a bug. (In the glider modes the behaviour has been fixed in the 9C S).
In Acro mode if you set the airbrake so it is activated by the throttle stick a near the low throttle position you still get the behaviour :
1. Set airbrakes to be operated the throttle stick moving below (say) 25% and conditioned by a switch.
2. Leave programming mode and switch the airbrake off with the switch.
3. Trim the model, (say) aileron trim.
4. Activate the switch but keep throttle above 25% so the airbrake is not activated.
5. Trim model aileron some more.
6. Oops ! No effect ! I tried moving the trim all the way and nothing happened ! That's weird, I'd better land and investigate...
7. ... See what's coming ?...
8. Reduce throttle below 25% to land....
9. Oh, now I know where all that aileron trim went !
10. Walk to field carrying a bin bag.
This is so well known and so well documented that I'm surprised Futaba hasn't issued a product recall. What happens when someone discovers this defect when they're flying a 1/3rd scale Boeing 707 at an air display ? The product liability issues must be tremendous...
So what are Futaba going to do to fix it ?
Boo