NACA 0018 Airfoil
The NACA 0018 is a thick symmetric airfoil — 18% thick, no camber. That depth gives it plenty of internal volume and stiffness, so it is chosen where structure matters as much as aerodynamics: struts, pylons, vertical-axis wind-turbine blades and thick structural members.
What the numbers mean
In the code 0018, the first two digits 00 mean the section is symmetric — it has no camber — and the last two digits 18 are the maximum thickness as 18% of the chord.
Aerodynamic characteristics
Symmetric, so no lift and no pitching moment at zero angle. At 18% thickness the boundary layer separates a little earlier, so the maximum lift is slightly lower than a 15% section even though the stall is soft. Drag is higher — this is a structural and symmetric-use section, not a low-drag wing.
| Property | Typical value |
|---|---|
| Zero-lift angle α₀ | 0° |
| Lift coefficient at 0° | 0 |
| Lift-curve slope | ≈ 0.11 /deg |
| Max lift coefficient Cl,max | ≈ 1.3–1.4 |
| Stall angle | ≈ 15–16° |
| Pitching moment Cm,c/4 | 0 |
Conditions: Reynolds number Re = 1×10⁶, low speed (Mach ≤ 0.15), smooth surface. Values are representative figures from thin-airfoil theory and published XFoil / wind-tunnel data, rounded for reference.
Where it's used
- Struts and pylons — a stiff, high-volume symmetric shape.
- Vertical-axis wind turbines — thick Darrieus blades that need structural depth.
- Structural members and fairings — where internal room and stiffness lead the choice.
- Thick tail roots — symmetric surfaces blended into a fuselage.
Coordinates
Surface coordinates as fractions of the chord (x/c, y/c), generated from the standard NACA 4-digit equations with a closed trailing edge. For the full high-resolution coordinate file, use the DAT export inside the explorer.
| x/c (upper) | y/c (upper) | x/c (lower) | y/c (lower) |
|---|---|---|---|
| 0.000 | +0.0000 | 0.000 | +0.0000 |
| 0.024 | +0.0388 | 0.024 | -0.0388 |
| 0.095 | +0.0691 | 0.095 | -0.0691 |
| 0.225 | +0.0879 | 0.225 | -0.0879 |
| 0.389 | +0.0876 | 0.389 | -0.0876 |
| 0.545 | +0.0747 | 0.545 | -0.0747 |
| 0.717 | +0.0520 | 0.717 | -0.0520 |
| 0.846 | +0.0306 | 0.846 | -0.0306 |
| 0.929 | +0.0148 | 0.929 | -0.0148 |
| 0.982 | +0.0039 | 0.982 | -0.0039 |
| 1.000 | -0.0000 | 1.000 | +0.0000 |
Explore NACA 0018 in the interactive tool →
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Open the explorer →Frequently asked questions
NACA 0018 is a thick symmetric NACA 4-digit airfoil with no camber and 18% maximum thickness, used mainly for struts, pylons and wind-turbine blades.
The 00 means symmetric (no camber) and the 18 is the maximum thickness as 18% of the chord.
The large thickness gives internal volume and bending stiffness, which matters for structural members, struts and turbine blades more than minimum drag does.
Its peak lift is a touch lower than a 15% symmetric section because the thicker shape separates slightly earlier, though the stall itself is gentle.