How does total drag change from stall speed to maximum IAS during straight and level flight at constant mass?

In straight and level flight at a constant mass, total drag behaves in a specific manner as the aircraft transitions from stall speed to maximum indicated airspeed (IAS). Initially, as airspeed increases from stall speed, the induced drag, which is a component of total drag, decreases because it is inversely proportional to the square of the airspeed. During this phase, the aircraft becomes more aerodynamically efficient, leading to a reduction in drag.

However, as the aircraft continues to increase speed beyond a certain point, the parasitic drag, which includes form drag and skin friction, begins to dominate. This drag component increases with the square of the speed. Thus, after reaching an initial decrease in total drag, the total drag begins to increase again due to the rising impact of parasitic drag.

Consequently, the total drag initially decreases with increasing speed but then starts to rise again as the aircraft approaches maximum IAS, resulting in the observed trend of total drag first decreasing and then increasing. This behavior is critical for pilots to understand, as it affects fuel efficiency, performance, and aircraft handling.