{
 "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": "propeller-blade-count",
 "name": "Propeller blade count (2, 3 and 4 blades)",
 "kind": "standard",
 "category": "Aircraft design",
 "group": "Propellers",
 "year": null,
 "question": "Should I use a 2-, 3- or 4-blade propeller?",
 "tags": [
  "vehicle design",
  "propellers",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "3 blade vs 2 blade prop",
  "propeller blade count",
  "4 blade prop rc",
  "3 blade prop equivalent",
  "how many prop blades",
  "multi blade propeller",
  "scale prop blade count",
  "prop blade number efficiency",
  "3 blade prop diameter"
 ],
 "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/propeller-blade-count/",
 "sheet_txt": "https://xemstudio.com/objects/propeller-blade-count/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": [
   "Adding blades lets a smaller-diameter prop absorb the same power. APC's rule: with the same blade shape and pitch, a 3-blade prop equals about 90% of a 2-blade's diameter and a 4-blade about 84% (Model Aviation, APC Q&A).",
   "This is useful for ground or scale clearance. The FAA notes large power increases drove four- and six-blade propellers on full-size aircraft (FAA Powerplant Handbook).",
   "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": [
    [
     "3-blade equivalent diameter",
     "about 90% of 2-blade",
     "Model Aviation (APC)"
    ],
    [
     "4-blade equivalent diameter",
     "about 84% of 2-blade",
     "Model Aviation (APC)"
    ],
    [
     "Worked example (derived)",
     "12x6 2-blade -> ~10.8x6 3-blade -> ~10.1x6 4-blade",
     "computed from APC rule"
    ],
    [
     "Reference build",
     "10.8 x 6, 3 blades",
     "computed"
    ]
   ]
  }
 },
 "sheet_text": "Propeller blade count (2, 3 and 4 blades) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/propeller-blade-count/  (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- Adding blades lets a smaller-diameter prop absorb the same power. APC's rule: with the same blade shape and pitch, a 3-blade prop equals about 90% of a 2-blade's diameter and a 4-blade about 84% (Model Aviation, APC Q&A).\n- This is useful for ground or scale clearance. The FAA notes large power increases drove four- and six-blade propellers on full-size aircraft (FAA Powerplant Handbook).\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\n3-blade equivalent diameter  about 90% of 2-blade  Model Aviation (APC)\n4-blade equivalent diameter  about 84% of 2-blade  Model Aviation (APC)\nWorked example (derived)  12x6 2-blade -> ~10.8x6 3-blade -> ~10.1x6 4-blade  computed from APC rule\nReference build  10.8 x 6, 3 blades  computed\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Model Aviation (AMA), J. Smith with APC Propellers: Common Questions with APC Propellers (Mar 2021) — web — Publisher's page; dimensions are facts — https://www.modelaviation.com/node/2115\n- FAA: Aviation Maintenance Technician Handbook - Powerplant, Ch. 7 Propellers — web — Publisher's page; dimensions are facts — https://www.faa.gov/sites/faa.gov/files/09_amtp_ch7.pdf\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/propeller-blade-count/index.json\nAPI: https://xemstudio.com/api/geometry?object=propeller-blade-count\n",
 "sources": [
  {
   "publisher": "Model Aviation (AMA), J. Smith with APC Propellers",
   "title": "Common Questions with APC Propellers (Mar 2021)",
   "url": "https://www.modelaviation.com/node/2115",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "FAA",
   "title": "Aviation Maintenance Technician Handbook - Powerplant, Ch. 7 Propellers",
   "url": "https://www.faa.gov/sites/faa.gov/files/09_amtp_ch7.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": [
  "propeller-diameter-vs-pitch",
  "pitch-diameter-ratio",
  "propeller-helix-angle-blade-twist",
  "propeller-slip-efficiency",
  "apc-propeller-rpm-limits",
  "apc-propeller-naming"
 ],
 "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": "What 3-blade replaces a 12x6?",
   "a": "About 10.8x6 by APC's 90% rule (Model Aviation)."
  }
 ],
 "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": "propeller-blade-count-propeller",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/propeller-blade-count/propeller-blade-count-propeller.step",
   "stl": "https://xemstudio.com/files/hardware/propeller-blade-count/propeller-blade-count-propeller.stl",
   "note": "10.8×6 in propeller, 3 blades: each section set at the geometric pitch angle atan(P / 2πr); chord and section illustrative"
  }
 ],
 "markdown": "https://xemstudio.com/objects/propeller-blade-count/index.md"
}