{
 "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": "sd8020-airfoil",
 "name": "SD8020 symmetric airfoil",
 "kind": "standard",
 "category": "Airfoils",
 "group": "Other airfoils",
 "year": null,
 "question": "What is the exact shape of the SD8020 symmetric airfoil?",
 "tags": [
  "airfoil",
  "wing section",
  "rc plane",
  "aerodynamics",
  "symmetric airfoil"
 ],
 "aliases": [
  "sd8020",
  "sd8020-010-88",
  "SD8020 symmetric airfoil",
  "SD8020 symmetric coordinates",
  "SD8020 symmetric dat",
  "SD8020 symmetric STEP",
  "SD8020 symmetric STL",
  "SD8020 symmetric profile"
 ],
 "overall_mm": {
  "length": 100,
  "width": 20,
  "height": 10.1
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/sd8020-airfoil/",
 "sheet_txt": "https://xemstudio.com/objects/sd8020-airfoil/sheet.txt",
 "sheet": {
  "basis": "Coordinates from the UIUC Airfoil Coordinates Database; thickness, camber and section by Xem Studio",
  "overall_mm": {
   "length": 100,
   "width": 20,
   "height": 10.1
  },
  "notes": [
   "SD8020 symmetric: Michael Selig and John Donovan (SD series). Maximum thickness 10.10 % of chord at 27.5 % chord; symmetric (no camber).",
   "Coordinates from the UIUC Airfoil Coordinates Database (M. Selig, UIUC Applied Aerodynamics Group), file sd8020.dat, titled 'SD8020-010-88'. Thickness and camber are computed by Xem Studio from those points (vertical distance at equal x, linear between points).",
   "The published trailing edge is sharp, so the section uses it as printed.",
   "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."
  ],
  "table": {
   "columns": [
    "parameter",
    "value",
    "source"
   ],
   "rows": [
    [
     "Max thickness",
     "10.10 % chord at 27.5 % chord",
     "computed from the UIUC coordinates"
    ],
    [
     "Max camber",
     "0 (symmetric)",
     "computed from the UIUC coordinates"
    ],
    [
     "Published points",
     "61 (31 upper, 31 lower, shared leading edge)",
     "UIUC coordinates"
    ],
    [
     "Trailing edge as published",
     "sharp (closed)",
     "UIUC coordinates"
    ],
    [
     "y at x = 1.25 % chord",
     "upper +1.448 / lower -1.447 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 2.5 % chord",
     "upper +2.111 / lower -2.111 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 5 % chord",
     "upper +2.964 / lower -2.964 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 7.5 % chord",
     "upper +3.549 / lower -3.549 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 10 % chord",
     "upper +3.977 / lower -3.977 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 15 % chord",
     "upper +4.554 / lower -4.554 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 20 % chord",
     "upper +4.863 / lower -4.863 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 25 % chord",
     "upper +5.012 / lower -5.012 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 30 % chord",
     "upper +5.042 / lower -5.042 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 40 % chord",
     "upper +4.841 / lower -4.840 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 50 % chord",
     "upper +4.383 / lower -4.383 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 60 % chord",
     "upper +3.737 / lower -3.737 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 70 % chord",
     "upper +2.946 / lower -2.946 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 80 % chord",
     "upper +2.052 / lower -2.052 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 90 % chord",
     "upper +1.100 / lower -1.100 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "y at x = 95 % chord",
     "upper +0.577 / lower -0.577 % chord",
     "linear between the published points (UIUC coordinates)"
    ],
    [
     "Coordinates source",
     "UIUC Airfoil Coordinates Database: sd8020.dat ('SD8020-010-88')",
     "UIUC Applied Aerodynamics Group (M. Selig)"
    ]
   ]
  }
 },
 "sheet_text": "SD8020 symmetric airfoil — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/sd8020-airfoil/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Coordinates from the UIUC Airfoil Coordinates Database; thickness, camber and section by Xem Studio\nCatalog version: 2026-10-20\n\nOverall (mm): length 100.0, width 20.0, height 10.1\n- SD8020 symmetric: Michael Selig and John Donovan (SD series). Maximum thickness 10.10 % of chord at 27.5 % chord; symmetric (no camber).\n- Coordinates from the UIUC Airfoil Coordinates Database (M. Selig, UIUC Applied Aerodynamics Group), file sd8020.dat, titled 'SD8020-010-88'. Thickness and camber are computed by Xem Studio from those points (vertical distance at equal x, linear between points).\n- The published trailing edge is sharp, so the section uses it as printed.\n- 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.\n\nparameter  value  source\nMax thickness  10.10 % chord at 27.5 % chord  computed from the UIUC coordinates\nMax camber  0 (symmetric)  computed from the UIUC coordinates\nPublished points  61 (31 upper, 31 lower, shared leading edge)  UIUC coordinates\nTrailing edge as published  sharp (closed)  UIUC coordinates\ny at x = 1.25 % chord  upper +1.448 / lower -1.447 % chord  linear between the published points (UIUC coordinates)\ny at x = 2.5 % chord  upper +2.111 / lower -2.111 % chord  linear between the published points (UIUC coordinates)\ny at x = 5 % chord  upper +2.964 / lower -2.964 % chord  linear between the published points (UIUC coordinates)\ny at x = 7.5 % chord  upper +3.549 / lower -3.549 % chord  linear between the published points (UIUC coordinates)\ny at x = 10 % chord  upper +3.977 / lower -3.977 % chord  linear between the published points (UIUC coordinates)\ny at x = 15 % chord  upper +4.554 / lower -4.554 % chord  linear between the published points (UIUC coordinates)\ny at x = 20 % chord  upper +4.863 / lower -4.863 % chord  linear between the published points (UIUC coordinates)\ny at x = 25 % chord  upper +5.012 / lower -5.012 % chord  linear between the published points (UIUC coordinates)\ny at x = 30 % chord  upper +5.042 / lower -5.042 % chord  linear between the published points (UIUC coordinates)\ny at x = 40 % chord  upper +4.841 / lower -4.840 % chord  linear between the published points (UIUC coordinates)\ny at x = 50 % chord  upper +4.383 / lower -4.383 % chord  linear between the published points (UIUC coordinates)\ny at x = 60 % chord  upper +3.737 / lower -3.737 % chord  linear between the published points (UIUC coordinates)\ny at x = 70 % chord  upper +2.946 / lower -2.946 % chord  linear between the published points (UIUC coordinates)\ny at x = 80 % chord  upper +2.052 / lower -2.052 % chord  linear between the published points (UIUC coordinates)\ny at x = 90 % chord  upper +1.100 / lower -1.100 % chord  linear between the published points (UIUC coordinates)\ny at x = 95 % chord  upper +0.577 / lower -0.577 % chord  linear between the published points (UIUC coordinates)\nCoordinates source  UIUC Airfoil Coordinates Database: sd8020.dat ('SD8020-010-88')  UIUC Applied Aerodynamics Group (M. Selig)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- UIUC Applied Aerodynamics Group (M. Selig): UIUC Airfoil Coordinates Database: sd8020.dat ('SD8020-010-88') — web — UIUC Airfoil Coordinates Database, public research data; coordinates are facts, cited and linked, not rehosted — https://m-selig.ae.illinois.edu/ads/coord/sd8020.dat\n- UIUC Applied Aerodynamics Group (M. Selig): UIUC Airfoil Coordinates Database (original: Michael Selig and John Donovan (SD series)) — web — UIUC Airfoil Coordinates Database, public research data; coordinates are facts, cited and linked, not rehosted — https://m-selig.ae.illinois.edu/ads/coord_database.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/sd8020-airfoil/index.json\nAPI: https://xemstudio.com/api/geometry?object=sd8020-airfoil\n",
 "sources": [
  {
   "publisher": "UIUC Applied Aerodynamics Group (M. Selig)",
   "title": "UIUC Airfoil Coordinates Database: sd8020.dat ('SD8020-010-88')",
   "url": "https://m-selig.ae.illinois.edu/ads/coord/sd8020.dat",
   "formats": [
    "web"
   ],
   "license": "UIUC Airfoil Coordinates Database, public research data; coordinates are facts, cited and linked, not rehosted",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "UIUC Applied Aerodynamics Group (M. Selig)",
   "title": "UIUC Airfoil Coordinates Database (original: Michael Selig and John Donovan (SD series))",
   "url": "https://m-selig.ae.illinois.edu/ads/coord_database.html",
   "formats": [
    "web"
   ],
   "license": "UIUC Airfoil Coordinates Database, public research data; coordinates are facts, cited and linked, not rehosted",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "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",
  "s7075-airfoil",
  "sd7037-airfoil",
  "naca-2412-airfoil",
  "naca-0012-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": "How thick is the SD8020 symmetric?",
   "a": "Maximum thickness 10.10 % of chord at 27.5 % chord: 10.10 mm on a 100 mm chord (computed from the UIUC coordinates)."
  },
  {
   "q": "How much camber does the SD8020 symmetric have?",
   "a": "None: it is symmetric."
  },
  {
   "q": "How do I use it for my wing?",
   "a": "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."
  }
 ],
 "files_license": {
  "name": "Xem Studio Design License",
  "holder": "Xem Studio",
  "url": "https://xemstudio.com/license/",
  "note": "Xem Studio's own design: free to use, print, modify and sell things made from it; not to be republished or redistributed as files."
 },
 "offers": [
  {
   "file": "sd8020-airfoil-section-100mm-chord",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/sd8020-airfoil/sd8020-airfoil-section-100mm-chord.step",
   "stl": "https://xemstudio.com/files/hardware/sd8020-airfoil/sd8020-airfoil-section-100mm-chord.stl",
   "note": "SD8020 symmetric section, 100 mm chord × 20 mm span, 60 points from the published coordinates, single trailing-edge point (scale to your chord)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/sd8020-airfoil/index.md"
}