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NACA 0021 airfoil
What is the exact shape of the NACA 0021 airfoil, and what do the digits mean? · Standard part · basis: Computed from the NACA equations (Report 460 / Report 610, restated in NASA TM-4741)
Also called: NACA 0021, NACA 0021 coordinates, NACA 0021 dat, NACA 0021 profile, NACA 0021 DXF, NACA 0021 STEP, NACA 0021 STL, perfil NACA 0021, Profil NACA 0021, naca0021, NACA 0021 wing section
Exact dimensions. True size, with no printing tolerance added.
- length
- 100.0 mm
- width
- 20.0 mm
- height
- 21.0 mm
Notes
- NACA 0021: symmetric, 21 % thick.
- NACA 4-digit: first digit = maximum camber in % of chord, second = its position in tenths of chord, last two = maximum thickness in % of chord (NACA Report 460).
- Ordinates are in % of chord from the leading edge, computed from the published equations with the closed-trailing-edge thickness coefficient (−0.1036, as in NASA TM-4741). The original reports use an open trailing edge (−0.1015); the difference is under 0.03 % of chord near the trailing edge.
- 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.
NACA 0021 airfoil size chart
| x (% chord) | upper x | upper y | lower x | lower y |
|---|---|---|---|---|
| 0 | 0.000 | 0.000 | 0.000 | 0.000 |
| 1.25 | 1.250 | 3.314 | 1.250 | -3.314 |
| 2.5 | 2.500 | 4.576 | 2.500 | -4.576 |
| 5 | 5.000 | 6.221 | 5.000 | -6.221 |
| 7.5 | 7.500 | 7.350 | 7.500 | -7.350 |
| 10 | 10.000 | 8.195 | 10.000 | -8.195 |
| 15 | 15.000 | 9.354 | 15.000 | -9.354 |
| 20 | 20.000 | 10.040 | 20.000 | -10.040 |
| 25 | 25.000 | 10.396 | 25.000 | -10.396 |
| 30 | 30.000 | 10.501 | 30.000 | -10.501 |
| 40 | 40.000 | 10.150 | 40.000 | -10.150 |
| 50 | 50.000 | 9.251 | 50.000 | -9.251 |
| 60 | 60.000 | 7.957 | 60.000 | -7.957 |
| 70 | 70.000 | 6.359 | 70.000 | -6.359 |
| 80 | 80.000 | 4.500 | 80.000 | -4.500 |
| 90 | 90.000 | 2.389 | 90.000 | -2.389 |
| 95 | 95.000 | 1.232 | 95.000 | -1.232 |
| 100 | 100.000 | -0.000 | 100.000 | 0.000 |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| NACA (NASA Technical Reports Server) | Report 460: The characteristics of 78 related airfoil sections from tests in the variable-density wind tunnel (Jacobs, Ward, Pinkerton, 1933) | web | Publisher's page; dimensions are facts |
| NASA | TM-4741: Computer program to obtain ordinates for NACA airfoils (Ladson, Brooks, Hill, Sproles, 1996) | web | Publisher's page; dimensions are facts |
Free files
★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json
| naca-0021-airfoil-section-100mm-chord | NACA 0021 section, 100 mm chord × 20 mm span, closed trailing edge, 160 points from the equations (scale to your chord) | STEP · STL |
https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.Plain text: sheet.txt · JSON: /api/geometry?object=naca-0021-airfoil
Fits with
Questions
How thick is the NACA 0021?
Maximum thickness 21.00 % of chord at 29.9 % chord: 21.00 mm on a 100 mm chord.
Where is the NACA 0021's camber?
None: it is symmetric (upper and lower surfaces mirror).
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.