{
 "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": "swept-wing",
 "name": "Swept-back wing",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Wing planforms",
 "year": null,
 "question": "Why do some wings sweep back?",
 "tags": [
  "vehicle design",
  "wing planforms",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "swept wing",
  "swept back wing",
  "wing sweep angle",
  "why are wings swept",
  "swept wing rc",
  "swept wing tip stall",
  "sweepback dihedral effect",
  "swept wing washout",
  "critical mach sweep"
 ],
 "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/swept-wing/",
 "sheet_txt": "https://xemstudio.com/objects/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": [
   "Sweeping the wing raises its critical Mach number, since Mcr for a swept wing scales with 1/cos(sweep) (TU Delft AE1101); sweep is mainly worth it at transonic and supersonic speed.",
   "Sweepback adds a stable dihedral effect that grows with lift coefficient, so swept high-wing designs may even need anhedral (Kitplanes, Wainfan).",
   "On a swept-back wing the local angle of attack rises toward the tip, so washout is needed to keep the tips from stalling first (R/C Soaring Digest). NACA tests of a 45 deg swept wing showed severe pitch instability without fences (NACA RM A53I21).",
   "Used on: B-1 (variable sweep), Boeing 737.",
   "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": [
    [
     "Sweep measured at",
     "quarter-chord line (or LE/TE angles)",
     "ERAU (Leishman)"
    ],
    [
     "Example",
     "sweep 40 deg with Mcr 0.7 (worked example)",
     "TU Delft AE1101"
    ],
    [
     "NACA test wing",
     "45 deg sweep, AR 5.515, taper 0.532, 10% thick",
     "NACA RM A53I21"
    ],
    [
     "Reference build",
     "span 1000, root 250, tip 120, LE sweep 40 deg",
     "illustrative (TU Delft example angle)"
    ]
   ]
  }
 },
 "sheet_text": "Swept-back wing — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/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- Sweeping the wing raises its critical Mach number, since Mcr for a swept wing scales with 1/cos(sweep) (TU Delft AE1101); sweep is mainly worth it at transonic and supersonic speed.\n- Sweepback adds a stable dihedral effect that grows with lift coefficient, so swept high-wing designs may even need anhedral (Kitplanes, Wainfan).\n- On a swept-back wing the local angle of attack rises toward the tip, so washout is needed to keep the tips from stalling first (R/C Soaring Digest). NACA tests of a 45 deg swept wing showed severe pitch instability without fences (NACA RM A53I21).\n- Used on: B-1 (variable sweep), Boeing 737.\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\nSweep measured at  quarter-chord line (or LE/TE angles)  ERAU (Leishman)\nExample  sweep 40 deg with Mcr 0.7 (worked example)  TU Delft AE1101\nNACA test wing  45 deg sweep, AR 5.515, taper 0.532, 10% thick  NACA RM A53I21\nReference build  span 1000, root 250, tip 120, LE sweep 40 deg  illustrative (TU Delft example angle)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- TU Delft OpenCourseWare: AE1101 Introduction to Aerospace Engineering, Aerodynamics 6 — web — Publisher's page; dimensions are facts — https://ocw.tudelft.nl/wp-content/uploads/AE1101-Aero-6.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- R/C Soaring Digest: Twist Distributions for Swept Wings, Part 2 (June 2002) — web — Publisher's page; dimensions are facts — https://new.rcsoaringdigest.com/2002/06/twist-distributions-for-swept-wings/[pdf].pdf\n- NACA Ames (Cleary & Boddy), RM A53I21: Wind-Tunnel Investigation of a 45 deg Sweptback Wing ... Including the Effects of Fences (1953) — web — Publisher's page; dimensions are facts — https://ntrs.nasa.gov/api/citations/19930088248/downloads/19930088248.pdf\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\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/swept-wing/index.json\nAPI: https://xemstudio.com/api/geometry?object=swept-wing\n",
 "sources": [
  {
   "publisher": "TU Delft OpenCourseWare",
   "title": "AE1101 Introduction to Aerospace Engineering, Aerodynamics 6",
   "url": "https://ocw.tudelft.nl/wp-content/uploads/AE1101-Aero-6.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
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  {
   "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": "R/C Soaring Digest",
   "title": "Twist Distributions for Swept Wings, Part 2 (June 2002)",
   "url": "https://new.rcsoaringdigest.com/2002/06/twist-distributions-for-swept-wings/[pdf].pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NACA Ames (Cleary & Boddy), RM A53I21",
   "title": "Wind-Tunnel Investigation of a 45 deg Sweptback Wing ... Including the Effects of Fences (1953)",
   "url": "https://ntrs.nasa.gov/api/citations/19930088248/downloads/19930088248.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "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
  }
 ],
 "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",
  "forward-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 does a swept wing tip-stall?",
   "a": "The angle of attack seen by each section rises toward the tip, so washout is needed (R/C Soaring Digest)."
  }
 ],
 "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": "swept-wing-wing",
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   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/swept-wing/swept-wing-wing.step",
   "stl": "https://xemstudio.com/files/hardware/swept-wing/swept-wing-wing.stl",
   "note": "swept planform: span 1000, root 250, tip 120 mm, LE sweep 40°, dihedral 0°, NACA 2412"
  }
 ],
 "markdown": "https://xemstudio.com/objects/swept-wing/index.md"
}