# Eppler E817 hydrofoil section

> What is the exact shape of the Eppler E817 hydrofoil airfoil?

- Category: Airfoils › Other airfoils
- Kind: Standard part
- Basis: Coordinates from the UIUC Airfoil Coordinates Database; thickness, camber and section by Xem Studio
- Page: https://xemstudio.com/objects/eppler-e817-airfoil/ · JSON: https://xemstudio.com/api/geometry?object=eppler-e817-airfoil · Plain text: https://xemstudio.com/objects/eppler-e817-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 | 10.98 |

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

## Notes

- Eppler E817 hydrofoil: Richard Eppler (Eppler airfoil series; the UIUC file is titled 'Eppler 817 hydrofoil'). Maximum thickness 10.98 % of chord at 32.9 % chord; maximum camber 2.88 % of chord at 68.9 % chord.
- Coordinates from the UIUC Airfoil Coordinates Database (M. Selig, UIUC Applied Aerodynamics Group), file e817.dat, titled 'EPPLER 817 HYDROFOIL AIRFOIL'. 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 | 10.98 % chord at 32.9 % chord | computed from the UIUC coordinates |
| Max camber | 2.88 % chord at 68.9 % chord | computed from the UIUC coordinates |
| Published points | 67 (35 upper, 33 lower, shared leading edge) | UIUC coordinates |
| Trailing edge as published | sharp (closed) | UIUC coordinates |
| y at x = 1.25 % chord | upper +1.210 / lower -1.144 % chord | linear between the published points (UIUC coordinates) |
| y at x = 2.5 % chord | upper +1.839 / lower -1.708 % chord | linear between the published points (UIUC coordinates) |
| y at x = 5 % chord | upper +2.729 / lower -2.489 % chord | linear between the published points (UIUC coordinates) |
| y at x = 7.5 % chord | upper +3.426 / lower -3.062 % chord | linear between the published points (UIUC coordinates) |
| y at x = 10 % chord | upper +4.010 / lower -3.510 % chord | linear between the published points (UIUC coordinates) |
| y at x = 15 % chord | upper +4.941 / lower -4.119 % chord | linear between the published points (UIUC coordinates) |
| y at x = 20 % chord | upper +5.669 / lower -4.409 % chord | linear between the published points (UIUC coordinates) |
| y at x = 25 % chord | upper +6.224 / lower -4.422 % chord | linear between the published points (UIUC coordinates) |
| y at x = 30 % chord | upper +6.655 / lower -4.263 % chord | linear between the published points (UIUC coordinates) |
| y at x = 40 % chord | upper +7.189 / lower -3.591 % chord | linear between the published points (UIUC coordinates) |
| y at x = 50 % chord | upper +7.322 / lower -2.636 % chord | linear between the published points (UIUC coordinates) |
| y at x = 60 % chord | upper +7.052 / lower -1.571 % chord | linear between the published points (UIUC coordinates) |
| y at x = 70 % chord | upper +6.294 / lower -0.546 % chord | linear between the published points (UIUC coordinates) |
| y at x = 80 % chord | upper +4.758 / lower +0.270 % chord | linear between the published points (UIUC coordinates) |
| y at x = 90 % chord | upper +2.604 / lower +0.651 % chord | linear between the published points (UIUC coordinates) |
| y at x = 95 % chord | upper +1.392 / lower +0.539 % chord | linear between the published points (UIUC coordinates) |
| Coordinates source | UIUC Airfoil Coordinates Database: e817.dat ('EPPLER 817 HYDROFOIL AIRFOIL') | UIUC Applied Aerodynamics Group (M. Selig) |

## Where the files are

- UIUC Applied Aerodynamics Group (M. Selig): [UIUC Airfoil Coordinates Database: e817.dat ('EPPLER 817 HYDROFOIL AIRFOIL')](https://m-selig.ae.illinois.edu/ads/coord/e817.dat) — web — UIUC Airfoil Coordinates Database, public research data; coordinates are facts, cited and linked, not rehosted
- UIUC Applied Aerodynamics Group (M. Selig): [UIUC Airfoil Coordinates Database (original: Richard Eppler (Eppler airfoil series; the UIUC file is titled 'Eppler 817 hydrofoil'))](https://m-selig.ae.illinois.edu/ads/coord_database.html) — web — UIUC Airfoil Coordinates Database, public research data; coordinates are facts, cited and linked, not rehosted

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

Index: https://xemstudio.com/files/hardware/eppler-e817-airfoil/index.json · license: https://xemstudio.com/files/hardware/eppler-e817-airfoil/LICENSE.md

- eppler-e817-airfoil-section-100mm-chord: [STEP](https://xemstudio.com/files/hardware/eppler-e817-airfoil/eppler-e817-airfoil-section-100mm-chord.step) · [STL](https://xemstudio.com/files/hardware/eppler-e817-airfoil/eppler-e817-airfoil-section-100mm-chord.stl) — Eppler E817 hydrofoil section, 100 mm chord × 20 mm span, 66 points from the published coordinates, single trailing-edge point (scale to your chord)

## Questions

**How thick is the Eppler E817 hydrofoil?**

Maximum thickness 10.98 % of chord at 32.9 % chord: 10.98 mm on a 100 mm chord (computed from the UIUC coordinates).

**How much camber does the Eppler E817 hydrofoil have?**

Maximum camber 2.88 % of chord at 68.9 % chord (computed from the UIUC coordinates).

**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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