Vc speed is maximum continuous thrust (MCT) in level flight (determined by the balance between total drag and total thrust). Our predicted Vc speed is 189 m/s at 35km. However, I am only getting about 146 m/s.
Looking along the longitudinal axis (Z) it turns out the flight controls (FCDRAG) are creating 24,500 pounds of drag in level flight. The rest of the airframe (AFDRAG) is only 40,500 pounds!