{
 "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": "lippisch-reverse-delta-wig",
 "name": "Lippisch reverse-delta ground-effect craft",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Ground-effect design",
 "year": null,
 "question": "Why does the Lippisch WIG use a reverse delta wing?",
 "tags": [
  "vehicle design",
  "ground-effect design",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "lippisch wig",
  "reverse delta ground effect",
  "x-113",
  "lippisch ekranoplan",
  "airfish wig",
  "reverse delta wing rc wig",
  "lippisch planform",
  "ground effect boat wing",
  "wig craft rc model"
 ],
 "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/lippisch-reverse-delta-wig/",
 "sheet_txt": "https://xemstudio.com/objects/lippisch-reverse-delta-wig/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's planform has chord decreasing linearly from root to tip, which limits the longitudinal shift of the centre of pressure with height, combined with moderate AR above 3, inverse dihedral to hold the hull above water, and a large high tailplane (Rozhdestvensky).",
   "The X-113 reached L/D around 25 (Rozhdestvensky). Experiments show the reverse delta has delayed stall and higher L/D than a regular delta, and in ground effect its tip-vortex circulation rose 65% (Frontiers 2022 review).",
   "Effective in-ground-effect height for reverse deltas is given as below about 40-45% of chord, and 15 deg anhedral was selected in one study (Frontiers 2022).",
   "Used on: Lippisch X-113, Lippisch X-114, Airfish-3.",
   "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-113 L/D",
     "about 25",
     "Rozhdestvensky 2006"
    ],
    [
     "X-114 weight",
     "1.35 t",
     "Rozhdestvensky 2006"
    ],
    [
     "Lippisch AR",
     "above 3",
     "Rozhdestvensky 2006"
    ],
    [
     "Selected anhedral (study)",
     "15 deg",
     "Frontiers 2022"
    ],
    [
     "Effective height",
     "< 40-45% chord",
     "Frontiers 2022"
    ],
    [
     "Reverse delta CLmax",
     "1.175 at 38 deg",
     "Frontiers 2022"
    ],
    [
     "Reference build",
     "span 700, root 400 (AR 3.5), anhedral 15 deg, endplates 40",
     "computed"
    ]
   ]
  }
 },
 "sheet_text": "Lippisch reverse-delta ground-effect craft — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/lippisch-reverse-delta-wig/  (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's planform has chord decreasing linearly from root to tip, which limits the longitudinal shift of the centre of pressure with height, combined with moderate AR above 3, inverse dihedral to hold the hull above water, and a large high tailplane (Rozhdestvensky).\n- The X-113 reached L/D around 25 (Rozhdestvensky). Experiments show the reverse delta has delayed stall and higher L/D than a regular delta, and in ground effect its tip-vortex circulation rose 65% (Frontiers 2022 review).\n- Effective in-ground-effect height for reverse deltas is given as below about 40-45% of chord, and 15 deg anhedral was selected in one study (Frontiers 2022).\n- Used on: Lippisch X-113, Lippisch X-114, Airfish-3.\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-113 L/D  about 25  Rozhdestvensky 2006\nX-114 weight  1.35 t  Rozhdestvensky 2006\nLippisch AR  above 3  Rozhdestvensky 2006\nSelected anhedral (study)  15 deg  Frontiers 2022\nEffective height  < 40-45% chord  Frontiers 2022\nReverse delta CLmax  1.175 at 38 deg  Frontiers 2022\nReference build  span 700, root 400 (AR 3.5), anhedral 15 deg, endplates 40  computed\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/lippisch-reverse-delta-wig/index.json\nAPI: https://xemstudio.com/api/geometry?object=lippisch-reverse-delta-wig\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",
  "ekranoplan-wing-tail-layout",
  "tandem-wig-configuration",
  "power-augmented-ram-par",
  "wig-endplates"
 ],
 "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 reverse delta for WIG?",
   "a": "It keeps the centre of pressure from moving much as height changes, easing pitch stability (Rozhdestvensky)."
  }
 ],
 "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": "lippisch-reverse-delta-wig-wing",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/lippisch-reverse-delta-wig/lippisch-reverse-delta-wig-wing.step",
   "stl": "https://xemstudio.com/files/hardware/lippisch-reverse-delta-wig/lippisch-reverse-delta-wig-wing.stl",
   "note": "Lippisch reverse delta: straight leading edge, trailing edge swept forward to the tips, span 700, root 400 mm, anhedral 15°, endplates 40 mm (scale to your craft)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/lippisch-reverse-delta-wig/index.md"
}