Trimming
Much debate goes into this;
Are you trimming attitude or are you trimming speed? If you trim for attitude and before the speed is stable then within a short period of time, as the speed changes, you will become out of trim. You must be at the required speed to 'fine' trim.
Also remember the fixed pitch propellor rpm varies with speed and cannot be finally set until speed is stable.
So, you must achieve the required speed and have set the correct rpm before you can then fine trim. If you do not do this you will be always be chasing your tail.
You MUST therefore know the speed to be achieved, the power (RPM) required together with the correct attitude before a successful trim can be done.
Top of climb;
1) Adopt the correct S&L attitude and maintain height with elevator.
a) Maintain balance (ball in the middle).
2) achieve the correct speed.
3) Set RPM (maintain ball in the middle)
4) TRIM ( if you allow the attitude to change while trimming then the speed will change and you will therefore trim for the wrong speed and the wrong attitude - the RPM will also have changed. If this happens then stop trimming adjust attitude to re-establish the correct speed and retrim - re-check the RPM and adjust the trim as required)