If you have put in more than a little aileron or elevator trim on your transmitter, take it out of your transmitter and dial it in mechanically by changing length of control rods.
Reason:
When Ruby is first engaged, it assumes that the plane is trimmed with servos centered (1500 usecs). If this is not the case, it takes Ruby about 1-2 seconds of flight to determine the actual amount of trim that is needed. If much trim is needed, it will veer or pitch up/down during this time. This could be disconcerting during flight. Most importantly, these initial 1-2 seconds of misdirection can lead to failed launches in aided or autonomous mode.
If you've put in heavy trim on your transmitter during flight, land and take the trim out of your transmitter and dial it in mechanically as described above.
Reason:
Ruby assumes that the position of your aileron / elevator channels at the end of preflight represents "center". If you move aileron or elevator trim settings more than a little during flight, this might confuse Ruby into thinking that you're holding the stick away from center when it's actually centered. In aided or autonomous modes, this can cause the plane to fly endlessly in a circle that drifts downwind rather than hold desired course, or to fly faster or slower than normal cruise speed.
After you land and perform the next preflight, if you still have trim on your transmitter, Ruby will see the new correct "center" values that include the trim that you've put in and everything will work correctly other than possibly a brief "veer" and "dip" described above when Ruby is first engaged.
| 
