# Stirling engine configurations: which type needs which parts on this shelf

> What are the different types of Stirling engine and what parts does each one need?

- Category: Stirling engines › Guide
- Kind: List / guide
- Basis: Standard taxonomy (alpha / beta / gamma by cylinder arrangement; drive mechanism; free-piston and non-mechanical variants) with the parts list for each drawn from this library
- Page: https://xemstudio.com/objects/stirling-configurations-guide/ · JSON: https://xemstudio.com/api/geometry?object=stirling-configurations-guide · Plain text: https://xemstudio.com/objects/stirling-configurations-guide/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

## Notes

- Three cylinder arrangements: alpha (two pistons, hot and cold cylinders), beta (displacer and piston in one cylinder), gamma (displacer cylinder plus a separate power cylinder). Then the drive: crank + con-rod, bell crank, rhombic, Ross yoke, Scotch yoke, swash plate, or none (free-piston, Ringbom, thermoacoustic, fluidyne).
- Every row's parts exist on the shelf as free STEP/STL except the rotary-displacer type. Pick the row, open the linked objects, print the calibration coupons first, and the parts fit each other: Ø3 pins, Ø5 shafts, 623/608 bearings, 10 mL syringes, 16 ga tri-clamp bores and 2020 frames are the common interfaces throughout.
- An agent asked to 'design a beta Stirling with a rhombic drive for a 2 in tri-clamp spool' should pull: rhombic-drive-kit, tri-clamp-displacers-and-heads (Ø46 × 90 displacer, crank head), tri-clamp-spool (2 in × 6 in), tri-clamp-ferrule, tri-clamp-end-cap gasket, regenerator-and-heat-materials, brass-tube-ks (5 mm tube rod), ball-bearings-metric (623), crank-conrod-flywheel-kit (flywheel), tea-light-candles or copper-pipe-type-l-m heat exchangers, and printer-calibration-coupons.
- LES: this is the index the LES videos point at: 'the parts for every engine type are on one page'.

## Sizes

| type | mechanism | shelf objects | note |
|---|---|---|---|
| Gamma (crank) | displacer + separate power cylinder, 90° crank | crank-conrod-flywheel-kit, tri-clamp-displacers-and-heads, plastic-syringes, can-engine-printed-kit | easiest; LES can and tri-clamp engines |
| Beta (bell crank) | displacer and piston coaxial, bell crank + links | motion-mechanisms (bell crank, links), tri-clamp-displacers-and-heads | compact |
| Beta (rhombic drive) | counter-rotating crank gears, yokes | rhombic-drive-kit, spur-gears-involute | balanced, Philips |
| Alpha (V-twin) | two pistons 90° apart | alpha-twin-crank-90, plastic-syringes | highest specific power |
| Alpha (Ross yoke) | parallel cylinders, triangular rocker | ross-yoke-kit | straight-line motion |
| Scotch yoke / swash plate | sinusoidal or multi-cylinder | motion-mechanisms | no con-rod |
| Ringbom | free displacer on stops, crank piston | free-piston-core (stops), crank-conrod-flywheel-kit | semi-free-piston |
| Free-piston | flexures, gas springs, linear alternator | spiral-flexure-bearings, free-piston-core, linear-alternator-kit, nasa-fpse-references | NASA / Sunpower |
| LTD (coffee cup) | wide thin displacer, tiny piston | ltd-coffee-cup-engine-kit | runs on 15 K |
| Thermoacoustic (standing wave) | stack in a resonator, no pistons | thermoacoustic-stacks-and-resonators, tri-clamp-spool | LES main line |
| Thermoacoustic-Stirling (travelling wave, TASHE) | looped regenerator + resonator | regenerator-and-heat-materials, thermoacoustic-stacks-and-resonators, linear-alternator-kit | NASA TASHE |
| Fluidyne | water columns as pistons | fluidyne-manifold, copper-pipe-type-l-m | no moving parts |
| Lamina-flow (thermal lag) | one tube, one piston, no displacer | borosilicate-test-tubes, plastic-syringes, crank-conrod-flywheel-kit | simplest moving-part engine |
| Rotary displacer | rotating displacer in a drum | — (not on the shelf yet) | rare |

## Where the files are

- Wikipedia: [Stirling engine](https://en.wikipedia.org/wiki/Stirling_engine) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Rhombic drive](https://en.wikipedia.org/wiki/Rhombic_drive) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Thermoacoustic heat engine](https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine) — web — CC BY-SA 4.0 (text)
- Ohio University: [Stirling cycle machine analysis (Urieli)](https://www.ohio.edu/mechanical/stirling/) — web — Author's site
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Questions

**What is the difference between alpha, beta and gamma Stirling engines?**

Alpha: two pistons in two cylinders (hot, cold). Beta: a displacer and a power piston sharing one cylinder. Gamma: a displacer cylinder and a separate power cylinder joined by a passage. Same cycle, different packaging.

**Which Stirling engine is easiest to build?**

Gamma with a crank: the can engine or the 2 in tri-clamp gamma. The LTD is next (runs on a warm hand but needs flat plates). Thermoacoustic has no moving parts but needs a heater and tuning.

**Which Stirling type is best balanced?**

Beta with a rhombic drive: the two mirror cranks cancel side loads and shaking forces; it is why Philips used it.

## Fits with

- [Rhombic drive kit (Philips beta Stirling): twin crank gears, links, yokes, frame](https://xemstudio.com/objects/rhombic-drive-kit/)
- [Ross yoke kit (alpha Stirling with parallel cylinders)](https://xemstudio.com/objects/ross-yoke-kit/)
- [Alpha V-twin: 90° two-pin crank discs, V block, transfer tee](https://xemstudio.com/objects/alpha-twin-crank-90/)
- [LTD (low-temperature differential, coffee-cup) Stirling kit: plates, chamber ring, displacer, top plate with syringe cylinder](https://xemstudio.com/objects/ltd-coffee-cup-engine-kit/)
- [Thermoacoustic stacks (slicer-infill blanks, spiral), resonator lengths and a speaker driver cap for tri-clamp spools](https://xemstudio.com/objects/thermoacoustic-stacks-and-resonators/)
- [Fluidyne (liquid-piston Stirling) manifold and tees for 1/2 in copper U-tubes](https://xemstudio.com/objects/fluidyne-manifold/)
- [Free-piston Stirling core: displacer, power piston, liner, gas spring, stops, clearance-seal and tuning tables](https://xemstudio.com/objects/free-piston-core/)
- [Crank discs, connecting rods and flywheels for model engines](https://xemstudio.com/objects/crank-conrod-flywheel-kit/)
- [Can-engine printed kit: can caps, diaphragm clamps, displacer guides, crank stands, CD/platter hubs, syringe cradles](https://xemstudio.com/objects/can-engine-printed-kit/)
- [Tri-clamp displacers and engine heads: 1.5, 2 and 3 in spools](https://xemstudio.com/objects/tri-clamp-displacers-and-heads/)
- [Motion mechanisms: Scotch yoke, swash (wobble) plate, eccentric + strap, Geneva, four-bar links, bell crank, rack](https://xemstudio.com/objects/motion-mechanisms/)