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Drive schematic of a wooden windmill (Dutch type) · Tokarnia

When the windmill works

The sails turn in plain view. Flour is made only at the end of the orange trace.

What else has to be connected?

The sails turn and the stones grind.

Schematic of the drive path in a Dutch-type windmill At top left, the wheel with sails. The windshaft leads to the great wheel; from there a stepped line runs down the upright shaft to the clutch, then horizontally under the millstones at bottom right. The orange trace shows how far the drive reaches; a black disc with a cross marks the break. Numbers 1 to 8 correspond to the links described in the section Three stops. This is a typological schematic, not a section of a specific historic building. 1 2 3 4 5 6 7 8 Schematic of the drive path in a Dutch-type windmill, vertical layout At the top, the wheel with sails, the windshaft and the great wheel. The upright shaft runs down to the clutch, then returns to the left under the millstones at the bottom. The orange trace shows how far the drive reaches; a black disc with a cross marks the break. Numbers 1 to 8 correspond to the links in the section Three stops. This is a typological schematic, not a section of a specific historic building. 1 2 3 4 5 6 7 8
End A · sails

Sails: turning (11 MU).

End B · stones

Stones: grinding (39 MU).

How to read the drawing. A typological schematic, not a section of a historic building. Figures in MU are model units, not measurements. Orange trace: how far the drive reaches. Disc with a cross: a break. Numbers 1–8: links from the section “Three stops”.

Showing the whole chain: the drive reaches through all 8 links.

Without JavaScript you see the starting state (working wind, cap facing the wind, optimal feed, clutch connected). The three cases calculated at once are described in the section “Same wind, three outcomes”.

Take the chain apart

Three stops along the drive path

The orange bar on the left shows how many links of a given stop receive the drive. Each decision has its result next to it; link numbers 1–8 are the same ones shown in the drawing at the top.

  1. Face the wind. The wind drives the sails with the part that hits their plane. In the model: thrust = wind level × cos² of the angle × 10 MU (an assumption inherited from V2, not a measurement).

    Wind (model level, not m/s)
    0°

    The slider works with the arrow keys, Home and End; the buttons are an alternative to dragging.

    Top view: wind and the plane of the sails Brown arrows on the left show the wind; the higher the level, the more arrows. The thick black line is the plane of the sails, the thin line is the axis of the windshaft. The orange section on the axis shows what part of the wind drives the sails; it shortens with the angle and disappears at 90 degrees.

    Top view. Arrows: wind. Thick line: plane of the sails. Orange section: the part of the wind that does the work (cos θ). Angle 0°: cos² = 1.00.

    • 1WindreachedWind level 2 (working); model scale 0–4, not m/s.
    • 2Cap into the windreachedCap at 0° to the wind: a thrust of 20 MU reaches the sails (cos² = 1.00).
    • 3Sails and windshaftreachedThe sails turn the windshaft: speed 11 MU.

  2. Connect the drive. The rotation of the sails passes through the great wheel on the windshaft, the pinion and the upright shaft to the stones. The brake holds the windshaft, so it stops everything; the clutch disconnects only the stones. The names of the parts and the way the stones are disengaged in a real building need confirmation.

    Clutch: connected

    Brake: released

    • 4Great wheel, pinion, upright shaftreachedThe rotation passes through the great wheel and the pinion to the upright shaft.
    • 5Stone clutchreachedClutch connected: the rotation continues on to the stones.
    • 6Runner stonereachedThe runner stone turns: speed 39 MU (model gearing ×3.5).

  3. Load with grain. Grain between the stones is a resistance that feeds back to the sails: a feed that is too heavy in weak wind chokes the whole chain. An empty hopper means the stones turn dry.

    Grain feed

    Thrust and resistance on one 0–72 MU scale

    Wind thrust20 MU
    Resistance16 MU

    Surplus +4 MU: the sails can turn.

    • 7Grain between the stonesreachedFeed 2 (optimal): grain reaches the space between the stones.
    • 8Flour in the binreachedFlour runs down into the bin.

Side-by-side comparison

Same wind, three outcomes

The same model calculated at once for three decisions of the miller, with the wind, cap and feed settings from the stops. Nothing needs to be saved or switched: the difference is visible in a single row.

Wind: level 2 (working) · cap: 0° · feed: 2 (optimal)

Clutch connected

The drive reaches through all 8 links.

Sails11 MU
Stones39 MU

The sails turn and the stones grind.

Clutch disconnected

The drive reaches link 4, break at link 5.

Sails21 MU
Stones0 MU

The sails turn. The stones do not grind: the clutch is disconnected.

Brake applied

The drive reaches link 2, break at link 3.

Sails0 MU
Stones0 MU

Nothing turns: the brake holds the shaft.

Common bar scale: 0–105 MU (model units, not revolutions per minute). In the model the stones turn 3.5 times faster than the sails (an assumption taken from V2), which is why their bars are longer. Disconnecting the stones takes load off the sails, so in the model they speed up. This is a property of the simplified model, not a risk assessment for a real windmill.

Explanation and limits

What this schematic shows and what it does not settle

This is a typological schematic

The drawing is not a section of the windmill from Grzymałków or a plan of its interior. The parts are arranged in steps and stretched so that the path of the drive can be seen; the number of wheels, the proportions and the way the stones are disengaged in a real building need confirmation from museum staff. The SVG drawing is the model's own work, with no third-party photographs.

The figures are model figures

Wind thrustwind level × cos²(cap angle) × 10 MU, rounded
Resistanceown friction 2 MU (when the wind blows) + feed 6 MU per level, +2 when there is grain in the hopper (only with the stones connected) + brake 50 MU
Sail speed0 when the surplus (thrust − resistance) ≤ 0 or the brake is applied; otherwise √surplus × 4.5 + 2, at most 30 MU
Stone speed3.5 × sail speed, only when the clutch is connected

Wind levels 0–4 are not speeds. V2 assigned them indicative m/s values; V3 does not repeat them, because the model gives no basis for thresholds. The page does not say when a real windmill may be started, braked or left unattended: that is a decision for museum staff.

Three questions for the guide

  1. With what, and from where, are the stones disengaged from the drive in this windmill?The schematic shows a “clutch”. In a real building it may be a different solution, and its name and operation need confirmation.
  2. Where does the brake rope converge, and from what level can it be pulled?A question from V2: it decides whether the miller could stop the shaft without going under the cap.
  3. Is the demonstration done dry or with grain, and how are the stones protected?A question from V2: turning the stones without grain makes them grind against each other, so it is worth asking about the museum's practice.

What remains of the V2 material (to be checked against the sources)

  • A wooden Dutch-type windmill from Grzymałków in the Ethnographic Park in Tokarnia; according to V2 it was built in 1931 in Pakuły and moved to Grzymałków in 1947. Octagonal body, three storeys.
  • The cap with the sails turns; the body stands still. V2 mentions a wooden tailpole for turning the cap and a steel rail with trolleys.
  • You cannot find out from this page when the windmill works: a demonstration depends on the Park's programme, staff, weather and the rules of monument protection. Check the organiser's calendar.

V2 embedded a photograph of the windmill (Dawid Galus, Wikimedia Commons, CC BY-SA 3.0 PL) from the internet. V3 does not load it, so that the page works offline; the link is kept with attribution, and the licence status needs checking at the source.

What was removed from V2 and why

  • The question notebook (saved in the browser) was replaced by three questions in the text; the page saves nothing.
  • The A/B comparator with saved scenarios gave way to three outcomes calculated at once. In V2, some comparison sentences searched the results for the text “0 rpm”, which the model never printed (the values carried the unit “MU”).
  • Four presets, a bar of four indicators and a +15° step were replaced by: a button for the starting state, two sentences about the ends of the system, a balance on one scale and the link-by-link mode.
  • The “New 30 attempts” link was removed as withdrawn.

Sources and links

The links were kept from V2 and from the reference catalogue; they were not opened at this stage, so we do not declare them verified. The model, units and drawing are a teaching illustration, not an operating manual or a conservation guide for the monument. The integration status (existence of the V1/V2 pages and the catalogue) is checked by the integrator.