{
 "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": "anhedral",
 "name": "Anhedral angle",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Wing planforms",
 "year": null,
 "question": "Why do some aircraft have drooping (anhedral) wings?",
 "tags": [
  "vehicle design",
  "wing planforms",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "anhedral",
  "anhedral wing",
  "negative dihedral",
  "cathedral wing",
  "anhedral vs dihedral",
  "why anhedral fighter",
  "anhedral high wing",
  "drooped wings aircraft",
  "anhedral rc"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/anhedral/",
 "sheet_txt": "https://xemstudio.com/objects/anhedral/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": [
   "Anhedral (tips below root) reduces roll stability; it is used on swept and high-wing designs that already have too much stable dihedral effect, and on fighters for roll rate (ERAU; NASA Glenn).",
   "Jets like the Harrier, Jaguar and Alpha Jet combine high wings, sweep and anhedral to get a small stable net effect; on a straight-wing light airplane anhedral 'will almost undoubtedly' make it laterally unstable (Kitplanes).",
   "On ground-effect craft anhedral tips trap a high-pressure air tunnel; a reverse-delta study chose 15 deg anhedral (Frontiers 2022 review).",
   "Used on: C-5 Galaxy, Harrier, SEPECAT Jaguar, Alpha Jet, Wright 1903 Flyer.",
   "The file is a reference example built by Xem Studio from the numbers above. Sizes the sources do not fix are illustrative; scale the example to your own vehicle."
  ],
  "table": {
   "columns": [
    "parameter",
    "value or range",
    "source"
   ],
   "rows": [
    [
     "Wright 1903 Flyer",
     "slight anhedral",
     "NASA Glenn"
    ],
    [
     "WIG reverse-delta study",
     "anhedral 8-45 deg tested; 15 deg selected",
     "Frontiers 2022 review"
    ],
    [
     "Reference build",
     "high swept wing, -3 deg",
     "illustrative"
    ]
   ]
  }
 },
 "sheet_text": "Anhedral angle — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/anhedral/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\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- Anhedral (tips below root) reduces roll stability; it is used on swept and high-wing designs that already have too much stable dihedral effect, and on fighters for roll rate (ERAU; NASA Glenn).\n- Jets like the Harrier, Jaguar and Alpha Jet combine high wings, sweep and anhedral to get a small stable net effect; on a straight-wing light airplane anhedral 'will almost undoubtedly' make it laterally unstable (Kitplanes).\n- On ground-effect craft anhedral tips trap a high-pressure air tunnel; a reverse-delta study chose 15 deg anhedral (Frontiers 2022 review).\n- Used on: C-5 Galaxy, Harrier, SEPECAT Jaguar, Alpha Jet, Wright 1903 Flyer.\n- The file is a reference example built by Xem Studio from the numbers above. Sizes the sources do not fix are illustrative; scale the example to your own vehicle.\n\nparameter  value or range  source\nWright 1903 Flyer  slight anhedral  NASA Glenn\nWIG reverse-delta study  anhedral 8-45 deg tested; 15 deg selected  Frontiers 2022 review\nReference build  high swept wing, -3 deg  illustrative\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Embry-Riddle (Leishman), Introduction to Aerospace Flight Vehicles: Wing Shapes and Nomenclature — web — Publisher's page; dimensions are facts — https://eaglepubs.erau.edu/introductiontoaerospaceflightvehicles/chapter/wing-shapes-and-nomenclature/\n- NASA Glenn Research Center: Beginner's Guide to Aeronautics: Wing Geometry — web — Publisher's page; dimensions are facts — https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/wing-geometry\n- Kitplanes (B. Wainfan): Wind Tunnel: Roll's role in lateral stability (2008) — web — Publisher's page; dimensions are facts — https://www.kitplanes.com/wind-tunnel-135/\n- Frontiers in Aerospace Engineering (2022): Review of ground-effect experiments on rectangular, reverse-delta and delta wings — web — Publisher's page; dimensions are facts — https://www.frontiersin.org/journals/aerospace-engineering/articles/10.3389/fpace.2022.975158/pdf\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/anhedral/index.json\nAPI: https://xemstudio.com/api/geometry?object=anhedral\n",
 "sources": [
  {
   "publisher": "Embry-Riddle (Leishman), Introduction to Aerospace Flight Vehicles",
   "title": "Wing Shapes and Nomenclature",
   "url": "https://eaglepubs.erau.edu/introductiontoaerospaceflightvehicles/chapter/wing-shapes-and-nomenclature/",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NASA Glenn Research Center",
   "title": "Beginner's Guide to Aeronautics: Wing Geometry",
   "url": "https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/wing-geometry",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Kitplanes (B. Wainfan)",
   "title": "Wind Tunnel: Roll's role in lateral stability (2008)",
   "url": "https://www.kitplanes.com/wind-tunnel-135/",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Frontiers in Aerospace Engineering (2022)",
   "title": "Review of ground-effect experiments on rectangular, reverse-delta and delta wings",
   "url": "https://www.frontiersin.org/journals/aerospace-engineering/articles/10.3389/fpace.2022.975158/pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "rectangular-wing",
  "tapered-wing",
  "elliptical-wing",
  "swept-wing",
  "forward-swept-wing",
  "delta-wing"
 ],
 "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": "Should a straight-wing RC plane have anhedral?",
   "a": "No; it will almost certainly be laterally unstable (Kitplanes)."
  }
 ],
 "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": "anhedral-wing",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/anhedral/anhedral-wing.step",
   "stl": "https://xemstudio.com/files/hardware/anhedral/anhedral-wing.stl",
   "note": "swept planform: span 1000, root 250, tip 120 mm, LE sweep 30°, dihedral -3°, NACA 2412"
  }
 ],
 "markdown": "https://xemstudio.com/objects/anhedral/index.md"
}