# Thermoacoustic burner drum: one torch heats one or three vertical 2 in tubes

> How do I heat the middle of a vertical tri-clamp tube with a propane torch?

- Category: Stirling engines › Thermoacoustic & fluidyne
- Kind: Hardware
- Basis: Hole and tube positions from the engine layouts in tools/gen_ta_power.py; Ø66 holes pass over a 2 in ferrule (Ø64)
- Page: https://xemstudio.com/objects/thermoacoustic-burner-drum/ · JSON: https://xemstudio.com/api/geometry?object=thermoacoustic-burner-drum · Plain text: https://xemstudio.com/objects/thermoacoustic-burner-drum/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## 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.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| tube holes | Ø66 | 2 in tube Ø50.8 (7.6 annulus, passes a Ø64 ferrule) | designed | all |
| tab holes | Ø4.5 | M4 clearance (ISO 273 medium) | designed | all |
| flue | Ø40 / Ø35 | torch flame (no contact) | designed | drum-ring-lower* |
| flue | Ø40 / Ø35 | torch flame (no contact) | designed | drum-single-lower* |

## Sizes

| file | diameter_mm | flue_mm |
|---|---|---|
| drum-ring-lower | 256.0 | 480.1 |
| drum-single-lower | 130.0 | 403.8 |

## Where the files are

- Xem Studio: [tools/gen_ta_power.py: the network model and every dimension on this page](https://xemstudio.com/) — code — CC BY 4.0
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (4 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/thermoacoustic-burner-drum/index.json

- drum-ring-lower: [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) — 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
- drum-ring-upper: [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) — ring drum upper half: three Ø66 tube holes, 8 × Ø8 and Ø12 vents over the centre, 3 tabs
- drum-single-lower: [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) — single drum lower half: Ø130 centred 22 in front of the tube, Ø66 tube hole, flue 403.8 down at y 64
- drum-single-upper: [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) — single drum upper half: tube hole, vents over the flue

## Questions

**Why a flue down to the bench?**

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.

## Fits with

- [Thermoacoustic fin sleeve: clamp-on, 2 in tube, 34 mm (optional)](https://xemstudio.com/objects/thermoacoustic-fin-sleeve/)
- [Torch stand for a horizontal tri-clamp hot leg](https://xemstudio.com/objects/tri-clamp-torch-stand/)
- [Thermoacoustic hot-head shroud: flame shroud and flue for a vertical 2 in tri-clamp core](https://xemstudio.com/objects/thermoacoustic-hot-shroud/)
- [Build list: Thermoacoustic-Stirling ring generator, three 2 in units, pressurised](https://xemstudio.com/objects/list-ta-ring-3x2in/)