Aerodynamics Practice Test

Wing-fuselage interference occurs where the wing meets the fuselage, causing their pressure fields to interact and disturb the nearby flow. This changes the pressure distribution around the junction, often increasing form or interference drag due to unfavorable pressure gradients and possible local flow separation. It can also alter the lift distribution, particularly near the root, which can reduce or shift lift in a way that degrades overall aerodynamic efficiency.

Design features like fairings, fillets, and smooth junctions help by smoothing the pressure transition, reducing local separations, and preserving a favorable lift distribution along the wing-fuselage junction. As a result, they decrease interference drag while maintaining the intended lift characteristics.

So, the statement that best captures the effect is that interference alters pressure distribution and can increase drag, with fairings and smooth junctions reducing interference drag and preserving lift distribution. The other possibilities don’t fit because interference does not always reduce drag, it affects more than weight, and it certainly has aerodynamic effects.