{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "thermoacoustic-burner-drum",
 "name": "Thermoacoustic burner drum: one torch heats one or three vertical 2 in tubes",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Thermoacoustic & fluidyne",
 "year": null,
 "question": "How do I heat the middle of a vertical tri-clamp tube with a propane torch?",
 "tags": [
  "burner",
  "shroud",
  "drum",
  "torch",
  "flue",
  "thermoacoustic",
  "tri-clamp",
  "long earth society"
 ],
 "aliases": [
  "burner shroud three tubes",
  "torch shroud vertical tube middle",
  "propane burner drum thermoacoustic"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 4,
 "url": "https://xemstudio.com/objects/thermoacoustic-burner-drum/",
 "sheet_txt": "https://xemstudio.com/objects/thermoacoustic-burner-drum/sheet.txt",
 "sheet": {
  "basis": "Hole and tube positions from the engine layouts in tools/gen_ta_power.py; Ø66 holes pass over a 2 in ferrule (Ø64)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A closed drum split across its height: the lower half carries a Ø40 flue straight down to a torch standing on the bench (the hot gas rises up it), the upper half the vents. The tubes pass through Ø66 holes, so each half slides over a 2 in ferrule; the halves join with three M4 × 20 through their tabs.",
   "Ring engine: one drum Ø256 round all three cores' hot zones, flue at the centre between them. Twin engine: a Ø130 drum with its flue in front of the core.",
   "Inside height 40: room for the optional fin sleeves. The annulus round each tube at the holes is a designed gap (3.6 mm).",
   "It runs at flame temperature; what it is made of is the builder's choice."
  ],
  "table": {
   "columns": [
    "file",
    "diameter_mm",
    "flue_mm"
   ],
   "rows": [
    [
     "drum-ring-lower",
     256,
     480.1
    ],
    [
     "drum-single-lower",
     130,
     403.8
    ]
   ]
  }
 },
 "sheet_text": "Thermoacoustic burner drum: one torch heats one or three vertical 2 in tubes — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/thermoacoustic-burner-drum/  (CC BY 4.0)\nBasis: Hole and tube positions from the engine layouts in tools/gen_ta_power.py; Ø66 holes pass over a 2 in ferrule (Ø64)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A closed drum split across its height: the lower half carries a Ø40 flue straight down to a torch standing on the bench (the hot gas rises up it), the upper half the vents. The tubes pass through Ø66 holes, so each half slides over a 2 in ferrule; the halves join with three M4 × 20 through their tabs.\n- Ring engine: one drum Ø256 round all three cores' hot zones, flue at the centre between them. Twin engine: a Ø130 drum with its flue in front of the core.\n- Inside height 40: room for the optional fin sleeves. The annulus round each tube at the holes is a designed gap (3.6 mm).\n- It runs at flame temperature; what it is made of is the builder's choice.\n\nfile  diameter_mm  flue_mm\ndrum-ring-lower  256.0  480.1\ndrum-single-lower  130.0  403.8\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Xem Studio: tools/gen_ta_power.py: the network model and every dimension on this page — code — CC BY 4.0 — https://xemstudio.com/\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 4 parts): https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/index.json\nAPI: https://xemstudio.com/api/geometry?object=thermoacoustic-burner-drum\n",
 "sources": [
  {
   "publisher": "Xem Studio",
   "title": "tools/gen_ta_power.py: the network model and every dimension on this page",
   "url": "https://xemstudio.com/",
   "formats": [
    "code"
   ],
   "license": "CC BY 4.0",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "thermoacoustic-fin-sleeve",
  "tri-clamp-torch-stand",
  "thermoacoustic-hot-shroud",
  "list-ta-ring-3x2in"
 ],
 "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": [
  {
   "feature": "tube holes",
   "exact": "Ø66",
   "mates": "2 in tube Ø50.8 (7.6 annulus, passes a Ø64 ferrule)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "tab holes",
   "exact": "Ø4.5",
   "mates": "M4 clearance (ISO 273 medium)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "flue",
   "exact": "Ø40 / Ø35",
   "mates": "torch flame (no contact)",
   "fit": "designed",
   "files": "drum-ring-lower"
  },
  {
   "feature": "flue",
   "exact": "Ø40 / Ø35",
   "mates": "torch flame (no contact)",
   "fit": "designed",
   "files": "drum-single-lower"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "Why a flue down to the bench?",
   "a": "The hot zones are half way up the cores, above the pistons; the flue brings the flame there while the torch stands safely on the bench."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "drum-ring-lower",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-ring-lower.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-ring-lower.stl",
   "note": "ring drum lower half: Ø256 × 22.5, walls 2.5, three Ø66 tube holes on r 80, Ø40 / Ø35 flue 480.1 down from the centre, 3 tabs"
  },
  {
   "file": "drum-ring-upper",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-ring-upper.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-ring-upper.stl",
   "note": "ring drum upper half: three Ø66 tube holes, 8 × Ø8 and Ø12 vents over the centre, 3 tabs"
  },
  {
   "file": "drum-single-lower",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-single-lower.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-single-lower.stl",
   "note": "single drum lower half: Ø130 centred 22 in front of the tube, Ø66 tube hole, flue 403.8 down at y 64"
  },
  {
   "file": "drum-single-upper",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-single-upper.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/drum-single-upper.stl",
   "note": "single drum upper half: tube hole, vents over the flue"
  }
 ],
 "markdown": "https://xemstudio.com/objects/thermoacoustic-burner-drum/index.md"
}