Selig S1223 airfoil — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/selig-s1223-airfoil/  (sheet CC BY 4.0)
Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
Catalog version: 2026-10-20

Sizes: see table below
- 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).

parameter  value or range  source
Design target  CLmax > 2 at Re 2e5  Selig & Guglielmo 1997
Measured CLmax (clean)  2.2 (Table 1: 2.23)  Selig & Guglielmo 1997
Cm c/4 (predicted)  -0.29  Selig & Guglielmo 1997
With 1% Gurney flap  CLmax 2.3  Selig & Guglielmo 1997
Design Re range  2e5-5e5  Selig & Guglielmo 1997
FX 63-137 / M06-13-128 CLmax  1.75 / 1.52  Selig & Guglielmo 1997
Coordinates source  Table 2 of the paper  Selig & Guglielmo 1997

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- University of Illinois (Selig & Guglielmo), Journal of Aircraft 1997: High-Lift Low Reynolds Number Airfoil Design (S1223) — web — Publisher's page; dimensions are facts — https://m-selig.web.engr.illinois.edu/pubs/GuglielmoSelig-1997-JofAC-S1223.pdf

No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.
API: https://xemstudio.com/api/geometry?object=selig-s1223-airfoil