Thanks a lot!!!

Here is what I understand:

So momentum = Mass*Velocity.
Momentum is always constant.*
Angular momentum = Mass*Velocity of a rotating object.
It is always equal.

When we pitch up, we create a torque so we tend to make the prop rotate ---> we change the velocity of the prop so the angular momentum. The prop tries to keep a constant velocity (mass won't change) and creates a yaw turn...

Am I right now?*

Thanks