# NREL S809 airfoil

> What is the exact shape of the NREL S809 airfoil?

- Category: Airfoils › Other airfoils
- Kind: Standard part
- Basis: Coordinates from NREL/SR-440-6918 Table 2; thickness, camber and section by Xem Studio
- Page: https://xemstudio.com/objects/nrel-s809-airfoil/ · JSON: https://xemstudio.com/api/geometry?object=nrel-s809-airfoil · Plain text: https://xemstudio.com/objects/nrel-s809-airfoil/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 100.0 | 20.0 | 20.96 |

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- NREL S809: D. M. Somers, for NREL (wind-turbine airfoil). Maximum thickness 20.96 % of chord at 38.2 % chord; maximum camber 0.96 % of chord at 82.3 % chord.
- Coordinates from Table 2 of D.M. Somers, 'Design and Experimental Results for the S809 Airfoil' (NREL/SR-440-6918, 1997). The table starts just after the leading edge; the chord-line origin (0, 0) is used as the leading-edge point. Thickness and camber are computed by Xem Studio from those points (vertical distance at equal x, linear between points).
- The published trailing edge is sharp, so the section uses it as printed.
- The file is a 100 mm chord section, 20 mm deep: scale it uniformly to your chord, or import the STEP and sweep or loft it into a wing. Thickness scales with chord; the shape is the same at any size.

## Sizes

| parameter | value | source |
|---|---|---|
| Max thickness | 20.96 % chord at 38.2 % chord | computed from NREL/SR-440-6918 Table 2 |
| Max camber | 0.96 % chord at 82.3 % chord | computed from NREL/SR-440-6918 Table 2 |
| Published points | 62 (32 upper, 31 lower, shared leading edge, the (0, 0) leading edge added) | NREL/SR-440-6918 Table 2 |
| Trailing edge as published | sharp (closed) | NREL/SR-440-6918 Table 2 |
| y at x = 1.25 % chord | upper +1.787 / lower -1.475 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 2.5 % chord | upper +2.705 / lower -2.254 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 5 % chord | upper +4.069 / lower -3.492 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 7.5 % chord | upper +5.104 / lower -4.569 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 10 % chord | upper +5.951 / lower -5.544 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 15 % chord | upper +7.300 / lower -7.230 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 20 % chord | upper +8.332 / lower -8.594 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 25 % chord | upper +9.114 / lower -9.665 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 30 % chord | upper +9.651 / lower -10.434 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 40 % chord | upper +10.106 / lower -10.804 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 50 % chord | upper +9.500 / lower -9.350 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 60 % chord | upper +7.724 / lower -6.819 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 70 % chord | upper +5.771 / lower -4.232 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 80 % chord | upper +3.900 / lower -2.014 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 90 % chord | upper +2.044 / lower -0.439 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| y at x = 95 % chord | upper +0.996 / lower -0.019 % chord | linear between the published points (NREL/SR-440-6918 Table 2) |
| Coordinates source | Design and Experimental Results for the S809 Airfoil, NREL/SR-440-6918 (1997), Table 2 (coordinates) | NREL (D.M. Somers) |

## Where the files are

- NREL (D.M. Somers): [Design and Experimental Results for the S809 Airfoil, NREL/SR-440-6918 (1997), Table 2 (coordinates)](https://www.osti.gov/biblio/437668) — web — US Government-sponsored report; coordinates are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/nrel-s809-airfoil/index.json · license: https://xemstudio.com/files/hardware/nrel-s809-airfoil/LICENSE.md

- nrel-s809-airfoil-section-100mm-chord: [STEP](https://xemstudio.com/files/hardware/nrel-s809-airfoil/nrel-s809-airfoil-section-100mm-chord.step) · [STL](https://xemstudio.com/files/hardware/nrel-s809-airfoil/nrel-s809-airfoil-section-100mm-chord.stl) — NREL S809 section, 100 mm chord × 20 mm span, 61 points from the published coordinates, single trailing-edge point (scale to your chord)

## Questions

**How thick is the NREL S809?**

Maximum thickness 20.96 % of chord at 38.2 % chord: 20.96 mm on a 100 mm chord (computed from NREL/SR-440-6918 Table 2).

**How much camber does the NREL S809 have?**

Maximum camber 0.96 % of chord at 82.3 % chord (computed from NREL/SR-440-6918 Table 2).

**How do I use it for my wing?**

Scale the 100 mm section to your chord (e.g. 180 mm chord = 180 % scale), then extrude or loft between root and tip sections. For a tapered wing, scale a root and a tip copy and loft between them.

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