{
 "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": "forward-swept-wing",
 "name": "Forward-swept wing",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Wing planforms",
 "year": null,
 "question": "What are the pros and cons of a forward-swept wing?",
 "tags": [
  "vehicle design",
  "wing planforms",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "forward swept wing",
  "forward sweep",
  "x-29 wing",
  "forward swept wing rc",
  "forward swept wing advantages",
  "swept forward wing divergence",
  "su-47 wing",
  "negative sweep wing",
  "forward swept glider"
 ],
 "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/forward-swept-wing/",
 "sheet_txt": "https://xemstudio.com/objects/forward-swept-wing/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": [
   "Leishman describes forward sweep as aeroelastically unstable and rarely used, because aerodynamic load twists the tips to higher incidence (ERAU).",
   "NASA's X-29 used composite aeroelastic tailoring, letting the wing bend but limiting twist to prevent divergence; reversed spanwise flow kept the tips and ailerons from stalling at high angle of attack, with good control to 45 deg (NASA FS-008).",
   "Forward sweep gives an unstable dihedral effect, so it needs more geometric dihedral than straight or swept-back wings (Kitplanes, Wainfan). The X-29 did not show the drag reduction earlier studies predicted (NASA).",
   "Used on: Grumman X-29.",
   "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": [
    [
     "X-29 span / length",
     "27.2 ft / 48.1 ft",
     "NASA FS-008"
    ],
    [
     "X-29 controllable AoA",
     "excellent to 45 deg; limited at 67 deg",
     "NASA FS-008"
    ],
    [
     "X-29 wash",
     "washin toward tip (forward-swept)",
     "ERAU (Leishman)"
    ],
    [
     "Reference build sweep",
     "-30 deg LE (illustrative; no published angle fetched)",
     "illustrative"
    ]
   ]
  }
 },
 "sheet_text": "Forward-swept wing — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/forward-swept-wing/  (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- Leishman describes forward sweep as aeroelastically unstable and rarely used, because aerodynamic load twists the tips to higher incidence (ERAU).\n- NASA's X-29 used composite aeroelastic tailoring, letting the wing bend but limiting twist to prevent divergence; reversed spanwise flow kept the tips and ailerons from stalling at high angle of attack, with good control to 45 deg (NASA FS-008).\n- Forward sweep gives an unstable dihedral effect, so it needs more geometric dihedral than straight or swept-back wings (Kitplanes, Wainfan). The X-29 did not show the drag reduction earlier studies predicted (NASA).\n- Used on: Grumman X-29.\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\nX-29 span / length  27.2 ft / 48.1 ft  NASA FS-008\nX-29 controllable AoA  excellent to 45 deg; limited at 67 deg  NASA FS-008\nX-29 wash  washin toward tip (forward-swept)  ERAU (Leishman)\nReference build sweep  -30 deg LE (illustrative; no published angle fetched)  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 Armstrong: X-29 Fact Sheet FS-008 — web — Publisher's page; dimensions are facts — https://www.nasa.gov/wp-content/uploads/2021/09/fs-008-afrc.pdf\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\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/forward-swept-wing/index.json\nAPI: https://xemstudio.com/api/geometry?object=forward-swept-wing\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 Armstrong",
   "title": "X-29 Fact Sheet FS-008",
   "url": "https://www.nasa.gov/wp-content/uploads/2021/09/fs-008-afrc.pdf",
   "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
  }
 ],
 "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",
  "delta-wing",
  "cranked-double-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": "Why aren't forward-swept wings common?",
   "a": "They tend toward structural divergence and need stiff, tailored structure (ERAU; NASA X-29)."
  }
 ],
 "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": "forward-swept-wing-wing",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/forward-swept-wing/forward-swept-wing-wing.step",
   "stl": "https://xemstudio.com/files/hardware/forward-swept-wing/forward-swept-wing-wing.stl",
   "note": "swept planform: span 1000, root 250, tip 120 mm, LE sweep -30°, dihedral 0°, NACA 2412"
  }
 ],
 "markdown": "https://xemstudio.com/objects/forward-swept-wing/index.md"
}