IṢẸ́ ỌNÀ
ẸWÀ ÀTI ÌLERA
IṢẸ́ ỌWỌ́
ÀṢÀ ÀTI ÌTÀN
ÌṢERÉ
ÀYÍKÁ
OÚNJẸ ÀTI OHUN MÍMU
REVERSE ENGINEERING
SÁYẸ́ǸSÌ
ERÉ ÌDÁRAYÁ
ÌMỌ̀-Ẹ̀RỌ
ÀWỌN OHUN WÍWỌ̀
The Savonius Rotor: Two Hollow Vanes, Any Wind, Always Starts
Cut a cylinder in half lengthwise, slide the halves apart so they overlap, and stand them on a vertical shaft: that is the rotor Sigurd Savonius of Finland patented in 1924–29. The wind pushes harder on the hollow of one vane than on the back of the other, and air flowing through the overlap from one hollow into the other helps it along.
It turns in wind from any direction without steering, starts itself in the lightest breeze, and gives strong torque at low speed — for pumping water, ventilating, or driving a current meter. It is also slow and inefficient, because it is pushed by drag.
This rung works out the drag machine's ceiling and builds a Savonius rotor from a PVC pipe, measuring its torque with a string brake.
Olùbẹ̀rẹ̀
About 4 hours
Ìlànà
1
1
Read Savonius's overlap
Read Savonius's overlap
US 1,697,574, 'Rotor Adapted to be Driven by Wind or Flowing Water', Sigurd J. Savonius. The vanes are *"hollow-shaped"* and *"overlapping"*, so that the space between them forms an air passage *"from the hollow side of the vane d, to the hollow side of the other vane c"*. His text compares it with the rotating cylinder then being studied at the Aerodynamische Versuchsanstalt in Göttingen, which it cites.
The overlap is the detail that separates a Savonius rotor from two cups on a stick.
2
2
The drag machine's ceiling
The drag machine's ceiling
Ń ṣí ìwé Jupyter…
3
3
Build it from a PVC pipe
Build it from a PVC pipe
Cut a 300 mm length of 110 mm PVC pipe in half lengthwise with a saw. Cut two plywood end discs 240 mm across. Screw the two half-pipes between the discs, hollow faces opposite, each shifted towards the centre so they **overlap by about a fifth of a half-pipe's width**, leaving the air passage Savonius describes.
Run a threaded-rod shaft through the centre of both discs, held by nuts, and carry it vertically in two skateboard bearings in a plywood frame.
Àwọn ohun èlò fún ìgbésẹ̀ yìí:
Páìpù PVC1 ẹyọ
Àwo igi tí a lẹ̀ pọ̀1 ewé
Ọ̀pá oníṣọ̀kan1 ẹyọ
Bearing Skateboard2 ẹyọ
Skurú ẹ̀rọ12 ẹyọÀwọn irinṣẹ́ tí a nílò:
Ẹ̀rọ Ìlùkòkò Aláìlókùn
Àkójọ Orí Ìlùkòkò
Kọ́kọ́rọ́ tí a lè ṣàtúnṣe
Ìdíwọ̀n
Ohun ìgé páìpù4
4
Measure torque with a string brake
Measure torque with a string brake
Wrap fishing line once round the shaft. Tie one end to the spring scale fixed to the frame, and hang a small weight on the other end, so the line rubs on the turning shaft as a brake. The braking torque is **(weight − scale reading) × shaft radius**.
Put the rotor in front of the box fan. Start with a light weight: the rotor spins fast. Add weight step by step, reading the speed with the tachometer and the scale each time, until it stalls. Power = torque × angular speed.
Turn the rotor to face the wind at a different angle: it does not care. Start the fan at its lowest setting with the rotor stopped: it starts by itself. Those two facts are why Savonius rotors exist.
Àwọn ohun èlò fún ìgbésẹ̀ yìí:
Okùn ìpẹja (okùn kan ṣoṣo)1 ìyípo
Ìwọ̀n1 ìtòÀwọn irinṣẹ́ tí a nílò:
Àbẹ̀bẹ̀ àpótí (ìwọ̀n tí ó ń yípadà)
Òǹwọ̀n atẹ́gùn olówọ́
Ìwọ̀n Ìyípo Dígítà
Ẹ̀rọ Ìwọ̀n Agbára (Òṣùwọ̀n Ìsúnkì)
Òṣùwọ̀n Kálípà Díjítà Ìnṣì 65
5
History and context
History and context
**US 1,697,574, 'Rotor Adapted to be Driven by Wind or Flowing Water', Sigurd J. Savonius; filed 13 August 1925 (Serial 49,985), claiming a Finnish filing of 12 December 1924; granted 1 January 1929.** The title names water as well as wind: the same rotor turns in a current.
**Honest limits.** Low efficiency — a drag machine cannot beat the notebook's ceiling by much. Heavy for its power, because the whole swept area is solid vane. Its torque pulses twice per turn, which is why many are built as two stages twisted 90° apart, or with helical vanes.
Àwọn ohun-èlò
7- 1 ẹyọÀyè
- 1 ewéÀyè
- 1 ẹyọÀyè
- Bearing Skateboardìdá 10%2 ẹyọÀyè
- 12 ẹyọÀyè
- 1 ìyípoÀyè
- 1 ìtòÀyè
Àwọn irinṣẹ́ tó nílò
10- 1 vendor sell this, none ship to you yetÀyè
- Àyè
- Ohun ìgé páìpùìdá 10%Àyè
Blueprint tó jọra
Àwọn blueprint wọ̀nyí pín ìmọ̀ — ọ̀nà, ohun-èlò tàbí ìlànà
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CC0 Àgbègbè Gbogbogbò
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