What happens to total drag when an aircraft changes its velocity away from L/Dmax AOA?

When an aircraft operates away from the lift-to-drag ratio maximum angle of attack (L/Dmax AOA), the total drag will generally increase. The L/Dmax AOA represents the point at which the aircraft achieves the most efficient lift-to-drag ratio, balancing the effects of induced drag and parasite drag.

As the aircraft's velocity changes from that optimal point, any increase or decrease in speed will shift the angle of attack away from the L/Dmax. If the aircraft is flying at a higher velocity, it is likely experiencing greater form drag due to increased skin friction and pressure drag. Similarly, if the aircraft slows down and the angle of attack increases, the induced drag will rise as well due to the larger lift being produced at lower speeds.

Therefore, moving away from the L/Dmax AOA leads to an increase in total drag because the aircraft is no longer operating in its most aerodynamically efficient range. Ultimately, this relationship emphasizes the importance of maintaining optimal airspeed and angle of attack for maximizing performance and minimizing drag during flight.