Increasing airfoil camber at a fixed angle of attack typically causes:

• A. Lift coefficient and lift increase; drag increases; stall angle decreases.
• B. Lift coefficient increases; drag increases; stall angle decreases.
• C. Lift coefficient increases; drag decreases; stall angle increases.
• D. Lift coefficient decreases; drag increases; stall angle decreases.

Answer: (A)

Increasing camber adds curvature to the airfoil, which changes the pressure distribution around it for a given angle of attack. The more pronounced curvature strengthens the suction on the upper surface, boosting the net pressure difference between the upper and lower surfaces. That larger pressure difference raises the lift coefficient at the same angle of attack, so lift increases.

At the same time, the tighter curvature enhances the adverse pressure gradient the boundary layer experiences as the flow continues over the surface. This makes separation start earlier as the angle increases, so the stall tends to occur at a lower angle of attack. The altered pressure field also tends to raise drag (more pressure-drag components and greater viscous losses), so drag increases as well.

In short: more camber increases lift at a fixed angle, increases drag, and tends to reduce the stall angle.