{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "selig-s1223-airfoil",
 "name": "Selig S1223 airfoil",
 "kind": "standard",
 "category": "Airfoils",
 "group": "Airfoils",
 "year": null,
 "question": "What is the S1223 high-lift airfoil?",
 "tags": [
  "vehicle design",
  "airfoils",
  "rc design",
  "aerodynamics",
  "guide"
 ],
 "aliases": [
  "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"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": false,
 "free_files": 0,
 "url": "https://xemstudio.com/objects/selig-s1223-airfoil/",
 "sheet_txt": "https://xemstudio.com/objects/selig-s1223-airfoil/sheet.txt",
 "sheet": {
  "basis": "Design rules and figures from the cited sources; example geometry by Xem Studio",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "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)."
  ],
  "table": {
   "columns": [
    "parameter",
    "value or range",
    "source"
   ],
   "rows": [
    [
     "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"
    ]
   ]
  }
 },
 "sheet_text": "Selig S1223 airfoil — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/selig-s1223-airfoil/  (sheet CC BY 4.0)\nBasis: Design rules and figures from the cited sources; example geometry by Xem Studio\nCatalog version: 2026-10-20\n\nSizes: see table below\n- 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.\n- The design uses concave pressure recovery with aft loading, giving a strongly nose-down moment (Cm c/4 about -0.29 predicted) (Selig & Guglielmo).\n- Stall is moderate when clean; a 1% Gurney raised CLmax to 2.3, while vortex generators made the stall abrupt with hysteresis (Selig & Guglielmo).\n- Used on: Pointer UAV (target class).\n\nparameter  value or range  source\nDesign target  CLmax > 2 at Re 2e5  Selig & Guglielmo 1997\nMeasured CLmax (clean)  2.2 (Table 1: 2.23)  Selig & Guglielmo 1997\nCm c/4 (predicted)  -0.29  Selig & Guglielmo 1997\nWith 1% Gurney flap  CLmax 2.3  Selig & Guglielmo 1997\nDesign Re range  2e5-5e5  Selig & Guglielmo 1997\nFX 63-137 / M06-13-128 CLmax  1.75 / 1.52  Selig & Guglielmo 1997\nCoordinates source  Table 2 of the paper  Selig & Guglielmo 1997\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- 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\n\nNo true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.\nAPI: https://xemstudio.com/api/geometry?object=selig-s1223-airfoil\n",
 "sources": [
  {
   "publisher": "University of Illinois (Selig & Guglielmo), Journal of Aircraft 1997",
   "title": "High-Lift Low Reynolds Number Airfoil Design (S1223)",
   "url": "https://m-selig.web.engr.illinois.edu/pubs/GuglielmoSelig-1997-JofAC-S1223.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "clark-y-airfoil",
  "eppler-e387-airfoil",
  "mh32-airfoil",
  "ag35-airfoil"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "Why is S1223 popular for heavy-lift RC?",
   "a": "It reaches CLmax about 2.2 at Re 200k (Selig & Guglielmo), far above typical sections, at the cost of a large nose-down moment."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/selig-s1223-airfoil/index.md"
}