A glide with an L/D ratio of 20:1 implies what?

A glide with an L/D ratio of 20:1 implies what?

• A. Travels 20 units forward for every 1 unit of altitude lost
• B. 1 unit forward for 20 units altitude lost
• C. 2 units forward for 1 unit altitude lost
• D. 40 units forward for 2 units altitude lost

Answer: (A)

Glide ratio expresses how far you can travel forward for each unit you lose in altitude. An L/D of 20:1 means you cover 20 units of forward distance for every 1 unit of altitude you descend. In still air and at the best glide speed, this is the efficiency you can expect: for every 1 unit of altitude dropped, you glide 20 units horizontally. So, if you lose 1,000 feet, you’d glide about 20,000 feet forward under those ideal conditions. Wind affects this in the real world: a headwind reduces the ground distance, while a tailwind increases it. The most straightforward way to express this ratio is exactly 20 units forward for every 1 unit of altitude lost, which is why that option is the best match. The alternative of 40 forward for 2 altitude lost is mathematically the same ratio but is not the conventional way to present the Glide ratio.

Glide ratio expresses how far you can travel forward for each unit you lose in altitude. An L/D of 20:1 means you cover 20 units of forward distance for every 1 unit of altitude you descend. In still air and at the best glide speed, this is the efficiency you can expect: for every 1 unit of altitude dropped, you glide 20 units horizontally.

So, if you lose 1,000 feet, you’d glide about 20,000 feet forward under those ideal conditions. Wind affects this in the real world: a headwind reduces the ground distance, while a tailwind increases it.

The most straightforward way to express this ratio is exactly 20 units forward for every 1 unit of altitude lost, which is why that option is the best match. The alternative of 40 forward for 2 altitude lost is mathematically the same ratio but is not the conventional way to present the Glide ratio.