I feel your pain. Had to fight messed up trims a few times.
Some tips I discuss when I am working with new folks in my club

1. On any problem, reduce throttle immediately to just enough to maintain minimum climb.
This will take a lot of the urgency out of the problem. Of all things, this is most often forgot, but simplest fix

2. Once slowed down, anaylize the problem step by step. What is the airplane doing? Roll? Pitch? Yaw?
I realize on a high wing trainer type rudder also gives roll. So what was likely happening was you were holding
opposite aileron to counter the trim induced yaw, causing the airplane to side slip as it climbed. This would give the mushy feeling.
Hopefully with the speed off you could tell if it is trying to toll or yaw and input correct trim.


3. Preflight! Cannot stress this one enough. In my days of non computer radios and manual trims I finally forced
myself into a prefight routine to verify control direction and overall centering. More part of an overall "get my brain in
flying mode" than a case of expecting controls to have reversed, etc....
Now I have a larger issue that preflight takes care of. Using a computer radio such as my Futaba 9CAFS, I have the capability
to store 36 models. I actually have about 14 that are flight capable. Add in pretty much everything I fly has dual aileron servos and sometimes flaps
that must be properly plugged in.
After losing a brand new U-Can-Do to reversed aileron travel (I mislabled the aileron extensions I leave plugged into receiver when
I finished initial setup and disassembly), and catching myself with the start shaft in my Raptor heli with the radio set on Funtana90, I
now have a pretty rigid preflight routine.
Before every flight
- check that radio is on correct channel assignment before turning on, and I have frequency pinned on freq. control board
- Power up radio and verify model name matches what I am planning to fly
- Verify elevator, rudder and ailerons move in correct direction. (This sounds too stupid to actually need to be checked, but doing this
would have saved my U-Can-Do, as the reversed servo plugs caused opposite aileron travel). For heli, add in check throttle/collective mixing working and
gyro coming up in heading hold mode
- Verify all contols are centered, or have correct offset for trimming that model
- Verify low rates/take off rates are set on radio, and any other mixes I do not want on take off are de-selected, such as elevator/flap,
rudder/elevator and such.
- verify throttle in proper start position
- Start engine and hopefully not have to tune.
- Verify control movement while engine running, just to sort out vibration induced issues.


4. Protecting your radio. Does not matter if it is a non computer 4 channel, or a high end computer radio, a transmitter case saves a lot of problems.
My Dad has been flying as long as I have, and still throws his radios in back of the Yukon with the planes. I have watched him fight trim issues
just like you.

5. Digital trims! Someone else already mentioned, but as you progress, go to a computer radio with digital trims. I thgink the Hitec Optic 6
is a fantastic radio for the price, and these days the 9C is getting pretty affordable as well.

Glad you got it back in one piece


jim