TURIN
Engines located at the base of the wing create positive interference at the most complex aerodynamic point the joint between the low-hung wing and the fuselage.
What's positive interference and negative interference?
The effect of the Jetstream causes the formation of an "active fairing" here, i.e., an increase in the "regeneration" of the surrounding flow.
What is an active fairing?
However, this engine arrangement requires an increase in the relative thickness of the airfoil profile, which causes a decrease in the aircraft's high-speed characteristics.
So the wing does behave thicker even if the lips are thinner than the other portions of the wing?