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Spoked flywheels Ø50 to Ø150 × 10
What size flywheel does a small Stirling engine need? · Hardware · basis: Rim Ø D × 10, five spokes 5 wide, Ø5 (Ø50) or Ø8 bore, radial M3 tapped hole
Long Earth Society build part. The crank train from the LES tri-clamp Stirling builds, parametrized. The engines
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. Mating features
- sizes
- 5 in table
Notes
- A Ø D × 10 wheel with five 5 mm spokes and a Ø5 (Ø50 wheel) or Ø8 (Ø80–150) bore; a radial Ø2.5 hole (M3 tap drill) at mid-thickness locks it to the shaft.
- Between the spokes the wheel is hollow inside: the band from 0.18 D radius to 8 mm inside the rim is a closed void with 1.5 mm faces on both sides.
- On the Ø80–Ø150 files the spoke ends stand proud of the rim; the overall size is in the table.
- Energy stored at a given speed goes with the fourth power of diameter, so diameter does more than thickness.
Sizes
| file | rim Ø | thickness | bore | overall (spoke ends) |
|---|---|---|---|---|
| flywheel-50 | 50 | 10 | 5 | 50 × 50 |
| flywheel-80 | 80 | 10 | 8 | 83.6 × 84.5 |
| flywheel-100 | 100 | 10 | 8 | 106.0 × 108.1 |
| flywheel-120 | 120 | 10 | 8 | 128.4 × 131.7 |
| flywheel-150 | 150 | 10 | 8 | 162.0 × 167.0 |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| flywheel bore | Ø5 / Ø8 | crankshaft (M3 set screw) | slide | flywheel-* |
| flywheel set-screw hole | Ø2.5 | M3 tap drill | designed | flywheel-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Wikipedia | Crank (mechanism) | web | CC BY-SA 4.0 (text) |
| Wikipedia | Flywheel | web | CC BY-SA 4.0 (text) |
| Wikipedia | Stirling engine | web | CC BY-SA 4.0 (text) |
| Long Earth Society | Engine builds that use these parts (videos and write-ups) | web, video | LES site |
Free files
★ Free files 5 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| flywheel-50 | spoked flywheel Ø50 × 10 overall: rim 8 wide (ID Ø34), hub Ø18, five spokes 5 wide × 7 thick on the mid-plane, open windows between; Ø5 bore, M3 set screw | STEP · STL |
| flywheel-80 | spoked flywheel Ø80 × 10 overall: rim 8 wide (ID Ø64), hub Ø28.8, five spokes 5 wide × 7 thick on the mid-plane, open windows between; Ø8 bore, M3 set screw | STEP · STL |
| flywheel-100 | spoked flywheel Ø100 × 10 overall: rim 8 wide (ID Ø84), hub Ø36, five spokes 5 wide × 7 thick on the mid-plane, open windows between; Ø8 bore, M3 set screw | STEP · STL |
| flywheel-120 | spoked flywheel Ø120 × 10 overall: rim 8 wide (ID Ø104), hub Ø43.2, five spokes 5 wide × 7 thick on the mid-plane, open windows between; Ø8 bore, M3 set screw | STEP · STL |
| flywheel-150 | spoked flywheel Ø150 × 10 overall: rim 8 wide (ID Ø134), hub Ø54, five spokes 5 wide × 7 thick on the mid-plane, open windows between; Ø8 bore, M3 set screw | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=spoked-flywheels
How it fits
Goes in or on
Crankshafts Ø3, Ø5 and Ø8 with full-length D-flatØ5 / Ø8 bore, M3 grub on the flatConnects to
Shaft adapter Ø5 to Ø8 × 20Ø8 bore on a Ø5 shaft
Bolt-on counterweight arcs R15, R20 and R25arc bolted opposite the crank pinAlternatives
Flywheels Ø100–Ø200 with hex-nut rim pocketsrim pockets carry hex nutsQuestions
How big a flywheel for a 2 in tri-clamp engine?
The 2 in engines run Ø100 × 10 on an Ø8 shaft.
What bore are the spoked flywheels?
Ø5 on the Ø50, Ø8 on the Ø80–150; the 5 → 8 shaft adapter puts an Ø8 wheel on a Ø5 shaft.