Hi OzExpat, it wasn't meant to be a cynical comment! As B2N2 said, these models are just about helping you understand the basics - it doesn't help you fly. All I was trying to say was that flying's about getting from A to B safely and that is far more about experience and training than technical discussions about forces. I'm a 200 hour PPL and I KNOW I have a huge amount to learn. Sorry if it appeared cynical.
You're right about the forces being out of equilibrium during the vertical acceleration stage between level and climbing at a constant rate. During the constant climb rate stage they are back in equilibrium.