See my other question here for the background context.
Consider this simple plane. I have applied the 4 basic forces: lift, drag, weight, and thrust. My question is, where, precisely, do I apply the lift force?
I've read through this which says it's at a quarter of the chord length. But where does that sit in 3 dimensional space? Most airliners have slightly swept wings. The chord length also changes along the wing. How can I model this mathematically?