Deviation from the best glide speed will lead to what effect on drag and glide distance?

Deviation from the best glide speed will lead to what effect on drag and glide distance?

• A. Drag decreases and glide distance increases
• B. Drag increases and glide distance decreases
• C. Drag decreases and glide distance unaffected
• D. Drag unaffected and glide distance decreases

Answer: (B)

Best glide speed is the speed at which the aircraft achieves its maximum lift-to-drag ratio, giving the greatest glide distance for a given altitude and weight. At this speed, the drag is minimized relative to the lift needed to sustain the descent, so you can travel the farthest before reaching the ground. If you fly slower than that speed, induced drag rises because the rotor (or wing) must produce more lift at lower speeds. The added induced drag makes the total drag higher, so the aircraft sinks steeper and covers less horizontal distance for the same altitude lost. If you fly faster than that speed, parasite drag (the drag from the airframe and components) increases with speed. The increase in total drag again reduces the glide ratio, so you don’t go as far horizontally for the same altitude lost. In short, moving away from the best glide speed worsens the glide ratio, so drag goes up and glide distance goes down.

Best glide speed is the speed at which the aircraft achieves its maximum lift-to-drag ratio, giving the greatest glide distance for a given altitude and weight. At this speed, the drag is minimized relative to the lift needed to sustain the descent, so you can travel the farthest before reaching the ground.

If you fly slower than that speed, induced drag rises because the rotor (or wing) must produce more lift at lower speeds. The added induced drag makes the total drag higher, so the aircraft sinks steeper and covers less horizontal distance for the same altitude lost.

If you fly faster than that speed, parasite drag (the drag from the airframe and components) increases with speed. The increase in total drag again reduces the glide ratio, so you don’t go as far horizontally for the same altitude lost.

In short, moving away from the best glide speed worsens the glide ratio, so drag goes up and glide distance goes down.