Keyboard control erratic on takeoff

I read about Understanding Propeller Torque and P-Factor and Gyroscopic Precession, but I don't understand why this also has an effect on jets (like 767, SR-71 Blackbird) - could someone "please explain" or link me to some info? 
I'm using the keyboard for rudder control, but it's still a struggle, and surely it's not also this difficult to control with stick yaw.
Cheers!

I'm using the keyboard for rudder control, but it's still a struggle, and surely it's not also this difficult to control with stick yaw.
Cheers!