# NACA 4421 airfoil

> What is the exact shape of the NACA 4421 airfoil, and what do the digits mean?

- Category: Airfoils › NACA 4-digit
- Kind: Standard part
- Basis: Computed from the NACA equations (Report 460 / Report 610, restated in NASA TM-4741)
- Page: https://xemstudio.com/objects/naca-4421-airfoil/ · JSON: https://xemstudio.com/api/geometry?object=naca-4421-airfoil · Plain text: https://xemstudio.com/objects/naca-4421-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 | 20.98 |

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

## Notes

- NACA 4421: 4 % camber at 40 % chord, 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.

## Sizes

| x (% chord) | upper x | upper y | lower x | lower y |
|---|---|---|---|---|
| 0 | 0.000 | 0.000 | 0.000 | 0.000 |
| 1.25 | 0.620 | 3.500 | 1.880 | -3.008 |
| 2.5 | 1.657 | 4.982 | 3.343 | -4.013 |
| 5 | 3.928 | 7.065 | 6.072 | -5.190 |
| 7.5 | 6.321 | 8.614 | 8.679 | -5.895 |
| 10 | 8.784 | 9.854 | 11.216 | -6.354 |
| 15 | 13.840 | 11.719 | 16.160 | -6.844 |
| 20 | 19.001 | 12.991 | 20.999 | -6.991 |
| 25 | 24.222 | 13.805 | 25.778 | -6.930 |
| 30 | 29.476 | 14.238 | 30.524 | -6.738 |
| 40 | 40.000 | 14.150 | 40.000 | -6.150 |
| 50 | 50.206 | 13.137 | 49.794 | -5.360 |
| 60 | 60.353 | 11.505 | 59.647 | -4.394 |
| 70 | 70.423 | 9.345 | 69.577 | -3.345 |
| 80 | 80.398 | 6.705 | 79.602 | -2.260 |
| 90 | 90.264 | 3.596 | 89.736 | -1.152 |
| 95 | 95.149 | 1.862 | 94.851 | -0.584 |
| 100 | 100.000 | -0.000 | 100.000 | 0.000 |

## Where the files are

- 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)](https://ntrs.nasa.gov/citations/19930091108) — web — Publisher's page; dimensions are facts
- NASA: [TM-4741: Computer program to obtain ordinates for NACA airfoils (Ladson, Brooks, Hill, Sproles, 1996)](https://www.pdas.com/refs/tm4741.pdf) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/naca-4421-airfoil/index.json · license: https://xemstudio.com/files/hardware/naca-4421-airfoil/LICENSE.md

- naca-4421-airfoil-section-100mm-chord: [STEP](https://xemstudio.com/files/hardware/naca-4421-airfoil/naca-4421-airfoil-section-100mm-chord.step) · [STL](https://xemstudio.com/files/hardware/naca-4421-airfoil/naca-4421-airfoil-section-100mm-chord.stl) — NACA 4421 section, 100 mm chord × 20 mm span, closed trailing edge, 160 points from the equations (scale to your chord)

## Questions

**How thick is the NACA 4421?**

Maximum thickness 20.98 % of chord at 30.3 % chord: 20.98 mm on a 100 mm chord.

**Where is the NACA 4421's camber?**

Maximum camber 4.00 % of chord at 40.0 % chord.

**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.

## Fits with

- [NACA 4409 airfoil](https://xemstudio.com/objects/naca-4409-airfoil/)
- [NACA 4412 airfoil](https://xemstudio.com/objects/naca-4412-airfoil/)
- [NACA 4415 airfoil](https://xemstudio.com/objects/naca-4415-airfoil/)
- [NACA 4418 airfoil](https://xemstudio.com/objects/naca-4418-airfoil/)
- [NACA 4424 airfoil](https://xemstudio.com/objects/naca-4424-airfoil/)