{
 "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": "tandem-wing",
 "name": "Tandem wing",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Tail configurations",
 "year": null,
 "question": "What is a tandem-wing aircraft and how does it stay stable?",
 "tags": [
  "vehicle design",
  "tail configurations",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "tandem wing",
  "tandem wing aircraft",
  "tandem wing rc",
  "flying flea",
  "pou du ciel",
  "two wing in line aircraft",
  "tandem wing stability",
  "tandem wing drone",
  "quickie tandem wing"
 ],
 "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/tandem-wing/",
 "sheet_txt": "https://xemstudio.com/objects/tandem-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": [
   "A tandem wing uses two lifting wings in line. The front wing gives pitch control and should stall first, which naturally limits angle of attack, comparable to a Rutan canard (Kitplanes, Flying Flea analysis).",
   "The Mignet HM.14 Flying Flea suffered fatal tuck-under dives; Baynes argued c.g. positions 'farther aft than 40% chord of the forward wing' made it unstable, and the vertical c.g. position added nonlinearity (Kitplanes).",
   "Once the c.g. was moved forward the rear wing carried little load; the Abbott-Baynes Cantilever Pou had a front wing almost twice the rear's area and was better seen as 'a monoplane with a large tail' (Kitplanes).",
   "Used on: Mignet HM.14 Pou-du-Ciel (Flying Flea), Abbott-Baynes Cantilever Pou, Mignet HM.293.",
   "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": [
    [
     "C.g. limit cited for the Flea",
     "not aft of 40% chord of the forward wing",
     "Kitplanes (Baynes)"
    ],
    [
     "Cantilever Pou front/rear wing area",
     "front almost 2x rear",
     "Kitplanes"
    ],
    [
     "Fatal Flea accidents",
     "at least 7 (possibly 11)",
     "Kitplanes"
    ],
    [
     "Reference build",
     "rear surface 300 x 60 mm at 500 mm (front wing is main wing)",
     "illustrative"
    ]
   ]
  }
 },
 "sheet_text": "Tandem wing — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tandem-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- A tandem wing uses two lifting wings in line. The front wing gives pitch control and should stall first, which naturally limits angle of attack, comparable to a Rutan canard (Kitplanes, Flying Flea analysis).\n- The Mignet HM.14 Flying Flea suffered fatal tuck-under dives; Baynes argued c.g. positions 'farther aft than 40% chord of the forward wing' made it unstable, and the vertical c.g. position added nonlinearity (Kitplanes).\n- Once the c.g. was moved forward the rear wing carried little load; the Abbott-Baynes Cantilever Pou had a front wing almost twice the rear's area and was better seen as 'a monoplane with a large tail' (Kitplanes).\n- Used on: Mignet HM.14 Pou-du-Ciel (Flying Flea), Abbott-Baynes Cantilever Pou, Mignet HM.293.\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\nC.g. limit cited for the Flea  not aft of 40% chord of the forward wing  Kitplanes (Baynes)\nCantilever Pou front/rear wing area  front almost 2x rear  Kitplanes\nFatal Flea accidents  at least 7 (possibly 11)  Kitplanes\nReference build  rear surface 300 x 60 mm at 500 mm (front wing is main wing)  illustrative\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Kitplanes (B. Wainfan): Wind Tunnel: More Flying Fleas (2017) — web — Publisher's page; dimensions are facts — https://www.kitplanes.com/wind-tunnel-65/\n- NASA Langley (D. Satran): Wind-Tunnel Investigation of the Flight Characteristics of a Canard General-Aviation Airplane Configuration, NASA TP-2623 (1986) — web — Publisher's page; dimensions are facts — https://ntrs.nasa.gov/api/citations/19870000606/downloads/19870000606.pdf\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/tandem-wing/index.json\nAPI: https://xemstudio.com/api/geometry?object=tandem-wing\n",
 "sources": [
  {
   "publisher": "Kitplanes (B. Wainfan)",
   "title": "Wind Tunnel: More Flying Fleas (2017)",
   "url": "https://www.kitplanes.com/wind-tunnel-65/",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NASA Langley (D. Satran)",
   "title": "Wind-Tunnel Investigation of the Flight Characteristics of a Canard General-Aviation Airplane Configuration, NASA TP-2623 (1986)",
   "url": "https://ntrs.nasa.gov/api/citations/19870000606/downloads/19870000606.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": [
  "tail-volume-coefficient",
  "tail-moment-arm",
  "conventional-tail",
  "t-tail",
  "cruciform-tail",
  "v-tail"
 ],
 "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": "Where should the c.g. be on a tandem wing?",
   "a": "Forward enough that the front wing stalls first; Baynes put the Flea's limit at 40% of the front wing chord (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": "tandem-wing-tail",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/tandem-wing/tandem-wing-tail.step",
   "stl": "https://xemstudio.com/files/hardware/tandem-wing/tandem-wing-tail.stl",
   "note": "canard layout: horizontal span 600 × chord 100, vertical 120 × 90 mm on a 500 mm boom, NACA 0009 surfaces"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tandem-wing/index.md"
}