Question

For an aircraft at a given altitude and velocity the induced drag is di. If the weight of the aircraft is increased by two times keeping altitude and velocity the same, what will be the new induced drag?

Answer 1

At higher altitudes, because of the less dense air, you need to fly at a higher angle of attack for a given true airspeed. And, if you're flying at a higher angle of attack, you're generating more induced drag. So, as you climb, your angle of attack for level flight increases and you generate moreinduced drag