A thin-airfoil lift/drag model, not a scripted flight path: lift and drag are recomputed every step from the current angle of attack, so trim and wind genuinely change how the plane flies instead of following a fixed animation.
- Lift coefficient CL ≈ 2π·α up to a ~16° stall, then falls off sharply.
- Drag coefficient CD = CD0 + k·CL², i.e. parasitic + induced drag.
- Forces: Flift = ½ρv²SCL (⊥ to velocity), Fdrag = ½ρv²SCD (∥ opposing velocity), plus gravity mg.
- Nose-weight trim shifts the plane's natural pitch, changing its cruise angle of attack — too much and it stalls; too little and it noses in.
α = pitch − flightPathAngle
CL(α) = clamp(2π·α, stall model)
a = (Flift + Fdrag + Fgravity) / m