There are some items I would check. If you have crashed one time or another you know that usually of of the motors takes a major hit. If you look at the motors you can see two cooling (if you will, vents) slots. When you are looking at the vents, see if a magnet has dropped to to where you can see it in the slot. If the magnet has dropped, the armature will not fully be in the magnetic field and subsequently will lose power. Two slots, two magnets. If they have dropped, just take a small screwdriver and push them back up into position. In my beginning flights (and crashes) I found this to be the case. Sometimes a motor in one location or another will begin to fail causing decreased lift to that plane. The Ti will try and compensate for this. It's basically cause and effect. The motor goes bad- the lift decreases. Some motors even though they all come off the same assembly line will have different outputs. If you crash into the ground you can jam dirt, grass, etc into the shaft bearing hole causing a motor shaft to have more friction-again, decreased lift is the result. I have found that if my motors get hot they react totally different to input as opposed to when they are cool. Try using quality heat-sinks on your motors.

Further, make sure that the connections between the capacitors and the motor teminals are solid. When you crash it is easy to dislodge these connections.

Make sure the motor pinion to main gear preload is appropriate. Sometimes the little mount that the rotor connects to can also get tweaked causing more friction between the pinion gear and main gear. Check this for both X and Y preloads.

Unless one half of a rotor is missing I suspect that this would not be something to worry about.

I agree, with scottslc. If the rotors are not perfectly on the same plane as the horizonal circuit board this would absolutely cause a control problem. I put the frame stiffener kit on mine to reduce this problem.

And finally when all else fails; you might consider the gyro for that particular plane (roll, pitch or yaw) could be going bad. One day I was flying my flyer perfectly. The next day it began to yaw really badly. I did everything I could to trim this out. Nothing worked. Finally I sent it back (again) to Spectrolutions and sure enough, the yaw gyro had gone south on me.

I hope this helps some.

C-ya

MJ