# NACA 0009 airfoil

> What is the exact shape of the NACA 0009 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-0009-airfoil/ · JSON: https://xemstudio.com/api/geometry?object=naca-0009-airfoil · Plain text: https://xemstudio.com/objects/naca-0009-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/)
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## Overall (mm)

| length | width | height |
|---|---|---|
| 100.0 | 20.0 | 9.0 |

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

## Notes

- NACA 0009 is a symmetric 4-digit section 9% chord thick (designation per NASA TM-4741). Being symmetric it makes no lift at zero angle and has zero moment about its aerodynamic centre, so it behaves the same upright and inverted (Virginia Tech Appendix A, on symmetric sections).
- Thin symmetric sections are the natural choice for tails and fins, which must lift either way; Drela's Bubble Dancer uses its own thin ht21 for both tail surfaces (CRRC).
- NACA 4-digit sections have good stall behaviour, small centre-of-pressure movement and low roughness sensitivity, but a low CLmax, relatively high drag and high pitching moment (Aerospaceweb summary).
- NACA 0009: symmetric, 9 % 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.
- Max thickness: 9% chord (from designation) (NASA TM-4741)
- Camber: 0 (symmetric) (NASA TM-4741)
- Zero-lift angle: 0 deg (symmetric section) (Virginia Tech Appendix A)
- Moment about a.c.: zero (symmetric; c.p. = a.c.) (Virginia Tech Appendix A)
- 4-digit code: 1st digit max camber %c; 2nd digit camber position in tenths c; last two thickness %c (NASA TM-4741; Aerospaceweb)
- Thickness equation (t/c = 0.20 basis): y/c = 0.2969 sqrt(x) - 0.1260 x - 0.3516 x^2 + 0.2843 x^3 - 0.1015 x^4, scaled by (t/c)/0.20 (NASA TM-4741)

## Sizes

| x (% chord) | upper x | upper y | lower x | lower y |
|---|---|---|---|---|
| 0 | 0.000 | 0.000 | 0.000 | 0.000 |
| 1.25 | 1.250 | 1.420 | 1.250 | -1.420 |
| 2.5 | 2.500 | 1.961 | 2.500 | -1.961 |
| 5 | 5.000 | 2.666 | 5.000 | -2.666 |
| 7.5 | 7.500 | 3.150 | 7.500 | -3.150 |
| 10 | 10.000 | 3.512 | 10.000 | -3.512 |
| 15 | 15.000 | 4.009 | 15.000 | -4.009 |
| 20 | 20.000 | 4.303 | 20.000 | -4.303 |
| 25 | 25.000 | 4.456 | 25.000 | -4.456 |
| 30 | 30.000 | 4.501 | 30.000 | -4.501 |
| 40 | 40.000 | 4.350 | 40.000 | -4.350 |
| 50 | 50.000 | 3.965 | 50.000 | -3.965 |
| 60 | 60.000 | 3.410 | 60.000 | -3.410 |
| 70 | 70.000 | 2.725 | 70.000 | -2.725 |
| 80 | 80.000 | 1.929 | 80.000 | -1.929 |
| 90 | 90.000 | 1.024 | 90.000 | -1.024 |
| 95 | 95.000 | 0.528 | 95.000 | -0.528 |
| 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
- NASA Langley (Ladson et al.), NASA TM-4741: [Computer Program to Obtain Ordinates for NACA Airfoils](https://www.pdas.com/refs/tm4741.pdf) — web — Publisher's page; dimensions are facts
- Virginia Tech Pressbooks (data from Abbott & von Doenhoff, NACA): [Appendix A: Airfoil Data](https://pressbooks.lib.vt.edu/aerodynamics/?p=52) — web — Publisher's page; dimensions are facts
- Aerospaceweb.org: [NACA Airfoil Series](https://aerospaceweb.org/question/airfoils/q0041.shtml) — web — Publisher's page; dimensions are facts
- Charles River Radio Controllers (M. Drela designs): [Bubble Dancer 3m RES sailplane](https://charlesriverrc.org/articles/on-line-plans/mark-drela-designs/bubble-dancer/) — 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-0009-airfoil/index.json · license: https://xemstudio.com/files/hardware/naca-0009-airfoil/LICENSE.md

- naca-0009-airfoil-section-100mm-chord: [STEP](https://xemstudio.com/files/hardware/naca-0009-airfoil/naca-0009-airfoil-section-100mm-chord.step) · [STL](https://xemstudio.com/files/hardware/naca-0009-airfoil/naca-0009-airfoil-section-100mm-chord.stl) — NACA 0009 section, 100 mm chord × 20 mm span, closed trailing edge, 160 points from the equations (scale to your chord)

## Questions

**Is NACA 0009 good for a stabiliser?**

It is thin and symmetric, so lifts equally both ways with zero a.c. moment (Virginia Tech Appendix A on symmetric sections).

**How thick is the NACA 0009?**

Maximum thickness 9.00 % of chord at 29.9 % chord: 9.00 mm on a 100 mm chord.

**Where is the NACA 0009'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.

## Fits with

- [NACA 0006 airfoil](https://xemstudio.com/objects/naca-0006-airfoil/)
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