I had a similar problem with a trainer once, I had so many landings that placed stress on the nosegear that it caused my rudder servo to develop a problem. When I would take off it would bank hard left. I determined the rudder was causing it to bank because the nosewheel was forcing it to turn. I replaced the servo and all linkages to the nosewheel and ruder and it was perfect again.

Could be a weak servo or control rods causing all of your problems.

let me know what you find out.

good luck