There is quite a lot of miss guilded info flyin' around here.
This isn't about Pfactor. It exists but has absolutely no effect on our small models.
This isnt about Torque. Torque is a twisting, not a yawing effect and has very little (read non) effect on any, even high powered models.
This is about the spirelling propeller slip stream hitting the left side of the vertical fin causing it to move over, thus creating the left yaw.
It can't be fixed (unless you use a counter rotating prop/ ducted fan etc), but it can be compensated for. There are two methods.
1. As mentioned: RIGHT THRUST.
The wonderful thing about right thrust is that it's proportional... set it for high power... and it's good for middle and low power settings.
2. Right rudder to throttle mix.
Once airborn, find out how much right rudder you need to imput to hold the model in a straight vertical climb using full power, then mix that amount to full throttle, half that amount to mid throttle ect.
From my experience, even though it's a real easy fix, far simpler than moving an engine around, it isn't as proportional as physical right thrust and will need a mixture curve to get a good feeling across the throttle range.
That's it and thats that.
There is one other factor that you should be aware of ... your Chipmunk has it's UC very close to the CG which make it very sensitive to ANY yaw effect on the ground... whether because of to little (or to much) right thrust, over compensated rudder inputs, offset or dragging wheels, a small dump on the runway etc. The only way to correctly set the right thrust is once airborn.
BTW, somebody mentioned that pattern pilots fly with there thumbs. Not the ones I hung around with!
They are adding washers, tweeking thrust angles, adding little bits of lead to wing tips etc so the DONT have to fly with thumbs.