AP4ATCO - Lift/Drag Ratio, Forces Interaction and Use/Answer 3
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The only effect that weight has is to vary the time for which the aircraft will glide. The heavier the aircraft is, the higher the airspeed must be to obtain the same glide ratio. If two aircraft have the same L/D ratio but different weights and start a glide from the same altitude, the heavier aircraft gliding at a higher airspeed will arrive at the same touchdown point in a shorter time. Both aircraft will cover the same distance but the lighter one will take a longer time to do so.