🪂 Glide vs Wind Reference
A glider’s glide ratio does not change with the wind — only the ground distance it buys. This grid shows what that costs, computed by the same glide ratio calculator this site runs. Each cell gives the ground glide and, beneath it, how far that reaches from 500 m above the landing area.
| Wing (still-air glide) | 25 head | 20 head | 15 head | 10 head | 5 head | Still | 10 tail | 20 tail |
|---|---|---|---|---|---|---|---|---|
| School / low-airtime wing 30 km/h @ 1 m/s → 8.33:1 | 1.39:1 695 m | 2.78:1 1,390 m | 4.17:1 2,085 m | 5.56:1 2,780 m | 6.94:1 3,470 m | 8.33:1 4,165 m | 11.11:1 5,555 m | 13.89:1 6,945 m |
| Typical recreational wing 38 km/h @ 1.2 m/s → 8.8:1 | 3.01:1 1,505 m | 4.17:1 2,085 m | 5.32:1 2,660 m | 6.48:1 3,240 m | 7.64:1 3,820 m | 8.8:1 4,400 m | 11.11:1 5,555 m | 13.43:1 6,715 m |
| Efficient recreational wing 38 km/h @ 1.1 m/s → 9.6:1 | 3.28:1 1,640 m | 4.55:1 2,275 m | 5.81:1 2,905 m | 7.07:1 3,535 m | 8.33:1 4,165 m | 9.6:1 4,800 m | 12.12:1 6,060 m | 14.65:1 7,325 m |
| Higher-performance wing 45 km/h @ 1.4 m/s → 8.93:1 | 3.97:1 1,985 m | 4.96:1 2,480 m | 5.95:1 2,975 m | 6.94:1 3,470 m | 7.94:1 3,970 m | 8.93:1 4,465 m | 10.91:1 5,455 m | 12.9:1 6,450 m |
Reading the grid
The penalty is bigger than it feels. A 9.6:1 wing into 20 km/h has a ground glide of 4.55:1 — it keeps 47.4% of its still-air reach. From 500 m that is 2,275 m instead of 4,800 m. Nothing is wrong with the wing; the ground is simply not cooperating.
Slow wings suffer most.Read the leftmost column down and the same headwind takes a larger share from each slower wing, because it is subtracted from a smaller airspeed. That is what pilots mean by penetration, and it is why the question “can I get back?” has a different answer on different equipment.
The downwind leg lies to you. Tailwind cells look generous, and a flight that went out easily can be one that cannot come back. Plan the return leg on the headwind figure, not on how the outbound felt.
What this grid cannot see: sinking air, which degrades the glide further and is commonly found near lift; wind gradient near the ground; gusts and rotor; and speed-to-fly, which can recover some ground glide into wind and is a trained skill rather than an arithmetic one. Use a glide measured from your own logs rather than a polar figure, take the conservative end of the spread, and keep options that do not depend on any of this being right. Final-glide decisions are made in the air by trained pilots — see what these numbers cannot tell you.
❓ Frequently Asked Questions
Does wind change my glider's glide ratio?
No. Glide ratio is a property of the wing in the air it is flying through, and it is unchanged by wind. What changes is the GROUND distance that ratio buys you. A 9.6:1 wing is still 9.6:1 into a headwind — but at 18 km/h over the ground instead of 38, so the ground glide falls to 4.55:1.
How much reach does a headwind actually cost?
From 500 m, a 9.6:1 wing can cover about 4,800 m in still air and about 2,275 m into 20 km/h — 47.4% of it. A pilot applying a still-air figure into that wind is planning for more than twice the distance available.
Why do slower wings suffer more?
Because the headwind is subtracted from your airspeed, and the same subtraction is a bigger fraction of a smaller number. A 30 km/h wing into 20 km/h of wind keeps a third of its groundspeed; a 45 km/h wing keeps well over half. That is why penetration is discussed as a property of faster, more heavily loaded wings.
Can I use this to plan a final glide?
No. This is a table for understanding the shape of the problem on the ground. It assumes a steady wind, otherwise neutral air, and a glide ratio you supplied — and real flights break all three, with sinking air being the most common. Final-glide judgement is taught and practised under supervision, and this page is not a substitute for it.