{
 "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": "wig-anhedral",
 "name": "Anhedral on ground-effect wings",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Ground-effect design",
 "year": null,
 "question": "Why do ground-effect craft wings droop?",
 "tags": [
  "vehicle design",
  "ground-effect design",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "wig anhedral",
  "ground effect anhedral",
  "anhedral reverse delta",
  "drooped wing ekranoplan",
  "inverse dihedral wig",
  "lippisch anhedral",
  "wig wing angle",
  "ground effect wing droop"
 ],
 "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/wig-anhedral/",
 "sheet_txt": "https://xemstudio.com/objects/wig-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": [
   "Lippisch craft used inverse dihedral so the tips or sponsons touch the water while the hull stays above it, forming a high-pressure 'air tunnel' under the wing (Rozhdestvensky; Frontiers 2022).",
   "On a reverse-delta wing tested at 8-45 deg anhedral, 15 deg was selected; at h/c near 0 the anhedral configuration gave lift increases of 270% (8 deg) and 150% (45 deg) over free flight (Frontiers 2022 review).",
   "Used on: Lippisch X-113.",
   "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": [
    [
     "Anhedral tested / selected",
     "8-45 deg / 15 deg",
     "Frontiers 2022"
    ],
    [
     "Lift increase at h/c ~ 0",
     "270% (8 deg), 150% (45 deg)",
     "Frontiers 2022"
    ],
    [
     "Reference build",
     "span 700, root 400, anhedral 15",
     "Frontiers 2022"
    ]
   ]
  }
 },
 "sheet_text": "Anhedral on ground-effect wings — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/wig-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- Lippisch craft used inverse dihedral so the tips or sponsons touch the water while the hull stays above it, forming a high-pressure 'air tunnel' under the wing (Rozhdestvensky; Frontiers 2022).\n- On a reverse-delta wing tested at 8-45 deg anhedral, 15 deg was selected; at h/c near 0 the anhedral configuration gave lift increases of 270% (8 deg) and 150% (45 deg) over free flight (Frontiers 2022 review).\n- Used on: Lippisch X-113.\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\nAnhedral tested / selected  8-45 deg / 15 deg  Frontiers 2022\nLift increase at h/c ~ 0  270% (8 deg), 150% (45 deg)  Frontiers 2022\nReference build  span 700, root 400, anhedral 15  Frontiers 2022\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Progress in Aerospace Sciences (K.V. Rozhdestvensky, 2006): Wing-in-ground effect vehicles (review) — web — Publisher's page; dimensions are facts — https://www.hassanhameed.com/wp-content/uploads/2016/01/wingingroundeffectvehicles-130120003005-phpapp01.pdf\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/wig-anhedral/index.json\nAPI: https://xemstudio.com/api/geometry?object=wig-anhedral\n",
 "sources": [
  {
   "publisher": "Progress in Aerospace Sciences (K.V. Rozhdestvensky, 2006)",
   "title": "Wing-in-ground effect vehicles (review)",
   "url": "https://www.hassanhameed.com/wp-content/uploads/2016/01/wingingroundeffectvehicles-130120003005-phpapp01.pdf",
   "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": [
  "ground-effect-height-span-ratio",
  "ground-effect-height-chord-ratio",
  "lippisch-reverse-delta-wig",
  "ekranoplan-wing-tail-layout",
  "tandem-wig-configuration",
  "power-augmented-ram-par"
 ],
 "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 much anhedral for a WIG model?",
   "a": "One reverse-delta study chose 15 deg (Frontiers 2022)."
  }
 ],
 "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": "wig-anhedral-wing",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/wig-anhedral/wig-anhedral-wing.step",
   "stl": "https://xemstudio.com/files/hardware/wig-anhedral/wig-anhedral-wing.stl",
   "note": "Lippisch reverse delta: straight leading edge, trailing edge swept forward to the tips, span 700, root 400 mm, anhedral 15° (scale to your craft)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/wig-anhedral/index.md"
}