Xem Studiomeasured geometry

Library › Airfoils › Airfoils ·

Selig S1223 airfoil

What is the S1223 high-lift airfoil? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: s1223, selig s1223, s1223 airfoil, s1223 coordinates, high lift airfoil, s1223 cl max, sae aero design airfoil, heavy lift rc airfoil, low reynolds high lift airfoil, s1223 dat

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

sizes
7 in table

Notes

  • S1223 was designed to exceed CLmax 2 at Re 200,000 for small UAVs; wind-tunnel tests gave 2.2 clean (Selig & Guglielmo, J. Aircraft 1997), 25% above the FX 63-137's 1.75.
  • The design uses concave pressure recovery with aft loading, giving a strongly nose-down moment (Cm c/4 about -0.29 predicted) (Selig & Guglielmo).
  • Stall is moderate when clean; a 1% Gurney raised CLmax to 2.3, while vortex generators made the stall abrupt with hysteresis (Selig & Guglielmo).
  • Used on: Pointer UAV (target class).

Selig S1223 airfoil size chart

parametervalue or rangesource
Design targetCLmax > 2 at Re 2e5Selig & Guglielmo 1997
Measured CLmax (clean)2.2 (Table 1: 2.23)Selig & Guglielmo 1997
Cm c/4 (predicted)-0.29Selig & Guglielmo 1997
With 1% Gurney flapCLmax 2.3Selig & Guglielmo 1997
Design Re range2e5-5e5Selig & Guglielmo 1997
FX 63-137 / M06-13-128 CLmax1.75 / 1.52Selig & Guglielmo 1997
Coordinates sourceTable 2 of the paperSelig & Guglielmo 1997

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

University of Illinois (Selig & Guglielmo), Journal of Aircraft 1997High-Lift Low Reynolds Number Airfoil Design (S1223)webPublisher's page; dimensions are facts

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Let your AI pull this. Add 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.
Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=selig-s1223-airfoil

Schematic, not to scale.

Fits with

Clark Y airfoil4 sizes★ sheet
Eppler E387 airfoil3 sizes★ sheet
MH 32 airfoil6 sizes★ sheet
AG35 airfoil (Drela AG series)5 sizes★ sheet

Questions

Why is S1223 popular for heavy-lift RC?

It reaches CLmax about 2.2 at Re 200k (Selig & Guglielmo), far above typical sections, at the cost of a large nose-down moment.