Crankcase flywheels: Ø44 × 12 disc and Ø42 pocket flywheel on a Ø3 shaft, inside a 2 in tri-clamp fitting — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/tri-clamp-crankcase-flywheel/  (CC BY 4.0)
Basis: Design values: Ø44 so the disc turns inside the 2 in bore (Ø47.5); Ø42 so the pocket flywheel turns in the bearing plate's Ø44 pocket inside the gasket lip (Ø45.3); inertia and the cycle's energy swing from the Schmidt estimate
Catalog version: 2026-10-20

Sizes: see table below
- Discs on the crankshaft between the crank and the bearing plates' spigots (one on +X, one on −X beside the crank gear), and a pocket flywheel on each shaft end in the bearing plate's pocket, 0.5 mm from the end cap. An M3 grub holds each.
- Why: nothing turns outside the vessel, so these, the crank gear and the generator's can (which turns 2.8 times faster, so counts 7.8 times its own inertia) are the whole flywheel. One cycle swings about 0.16 J against a steady load: a speed swing of 12–27 % at 900 rpm and 7–15 % at 1200 rpm for a disc density of 7.8 to 2.7 g/cm³ (the motor's turning part taken as 18 g at r 12.5).

file  size  bore  per engine
crank-flywheel-44x12-b3  Ø44 × 12  Ø3, radial M3 grub  2
pocket-flywheel-42x8-b3  Ø42 × 8 + Ø10 hub  Ø3, M3 grub  2

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Ohio University (I. Urieli): Stirling cycle machine analysis: the Schmidt (isothermal) analysis — web — university course pages [verify license at link] — https://www.ohio.edu/mechanical/stirling/isothermal/Schmidt.html
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 2 parts): https://xemstudio.com/files/hardware/tri-clamp-crankcase-flywheel/index.json
API: https://xemstudio.com/api/geometry?object=tri-clamp-crankcase-flywheel