4 ms·

Why do wind turbines have three blades?

55 points by greedo 1y ago

sema4hacker 1y ago
TL,DR: three blades (1) are a good balance of torque against drag at different speeds, (2) help reduce unbalanced forces compared to two-blade turbines, and (3) provide visual balance, smoother motion, and quieter operation to improve community acceptance.
jefurii 1y ago
Is it related to automobile wheels always seeming to have odd-numbered spokes?
- trenchpilgrim 1y ago
  There are plenty of six spoke wheels?
- potato3732842 1y ago
  That has to do with the physics of harmonic vibration. It's not that you can't make even numbers of spokes balanced, it's just marginally easier to do odd numbers. Back in ye-olden days when things sucked there were more manufacturing benefits to it too but these days (this century) that doesn't really matter because even the sloppiest casting factory in china has their stuff figured out.
brudgers 1y ago
The actual content, https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0 https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0
- throw0101c 1y ago
  > https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0 https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0 PSA: the si, as well as pp, parameter is used for tracking. If possible consider trimming them when copy-pasting.
  - brudgers 1y ago
    To the degree that kind of tracking significantly matters to you, there are alternatives that scale better and are more under your control. Personally, I doubt stripping the URL is going to meaningfully impact Google’s ability to track through Youtube. There are well paid, well funded, bonus motivated professionals who spend years throwing data science and computational expertise at the problem. They own search, the most popular browser, and handle a lot of DNS requests. Never mind that people tend to remain logged into their Youtube accounts, their Google accounts, and operate from the same handful of IP addresses through ISP’s who are happy to monetize data. Privacy theater is like security theater only less effective.
    - aendruk 1y ago
      It’s still a basic courtesy.
      - brudgers 1y ago
        BS. If you want to play make believe, that’s fine by me. However I don’t find it intellectually interesting.
miohtama 1y ago
There are companies working on two blade design, which has other benefits. You can try to get rid of balance problem with mechanical design and software: https://youtu.be/GbeFYLI8zYg?si=32wECCs05c4rRfs6 https://youtu.be/GbeFYLI8zYg?si=32wECCs05c4rRfs6
- weinzierl 1y ago
  We had the Growian two blade designs and its successor the Monopteros single blade design in the 80s. They were pretty famous back then and looked spectacular because of their sheer size and the unexpected asymmetry. Unfortunately they are almost forgotten now.
  - yread 1y ago
    There were a few 0.5MW NedWind 40/500 just out of Medemblik, decommisioned in 2016 though
- amelius 1y ago
  Reminds me of Dyson, who makes zero-blade fans. https://www.dyson.com/air-treatment/fans-heaters https://www.dyson.com/air-treatment/fans-heaters
  - 15155 1y ago
    These aren't zero-blade fans, they are normal multi-blade impellers that are piped into a duct.
  - rammer 1y ago
    Yes and this reminds me of Dyson fans vs the 15 $ fans video https://www.youtube.com/watch?v=dS0oFmzU06g https://www.youtube.com/watch?v=dS0oFmzU06g
    - amelius 1y ago
      Air purification would be a useful feature in windfarms, though.
HPsquared 1y ago
In some ways, a single blade is the most efficient. Not very good mechanically though!
rammer 1y ago
[flagged]
- Xss3 1y ago
  Imagine thinking the fossil fuel industry and politics had nothing to do with this utter bullshit report. What a wonderful world you must live in, ignorance is bliss.
- junto 1y ago
  The 2015 Australian Senate “wind turbines” report wasn’t neutral fact-finding, it was a politically driven hit job. The inquiry was stacked with senators openly hostile to renewables (John Madigan, Bob Day, David Leyonhjelm, Chris Back). At least one (Back) had direct ties to the oil & gas industry via Shell. Others were aligned with think tanks and lobbying groups that consistently push fossil-fuel interests. The report’s Chapter 7 hand-wrings about “subsidies” and “market distortions” while ignoring wind’s documented benefits: lower wholesale prices, emissions abatement, and diversification. It selectively cites contested modeling, downplays contrary evidence, and then leaps to prescriptive recommendations, like cutting subsidies, tightening planning laws, and federal overrides, which just happen to chill wind investment. Even Labor senators filed a dissent, accusing the majority of misrepresenting evidence and overreaching. Meanwhile, fossil-fuel lobbyists have long had privileged access to Australian policymakers through donations, revolving-door appointments, and consultancies (McKinsey, IPA, Barton Deakin, etc.). This wasn’t about “evidence”, simply it was about protecting fossil incumbents and kneecapping a competitor. Sources: - APH: Senate wind report, Chapter 7 - https://www.aph.gov.au/parliamentary_business/committees/senate/wind_turbines/wind_turbines/Final%20Report/c07 https://www.aph.gov.au/parliamentary_business/committees/sen... - Labor dissenting report: https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Wind_Turbines/Wind_Turbines/Final_Report/d01 https://www.aph.gov.au/Parliamentary_Business/Committees/Sen... - RenewEconomy critique - Chris Back’s oil/gas background: https://reneweconomy.com.au/senate-wind-report-slammed-as-reckless-biased-attack-on-renewables-14968/ https://reneweconomy.com.au/senate-wind-report-slammed-as-re... - InfluenceMap on fossil fuel lobbying: https://influencemap.org/pressrelease/Unearthed-Australia-Statement-13560 https://influencemap.org/pressrelease/Unearthed-Australia-St... - Guardian on McKinsey fossil fuel conflict: https://www.theguardian.com/australia-news/2024/dec/06/mckinsey-consultancy-firm-australian-climate-change-policy-fossil-fuel-companies-ntwnfb https://www.theguardian.com/australia-news/2024/dec/06/mckin...
imcritic 1y ago
AI slop produced by someone that needed to meet word count criteria.
- tentacleuno 1y ago
  Perhaps that's an overly cynical take? It doesn't read like AI slop to me, more like an overview of the video. As someone who finds it hard to get solid answers online anymore, I found this article genuinely informative (though, of course, the video provides the most value.)
  - em-bee 1y ago
    the point of the article/website appears to be to collect useful resources. as such it probably works better than trying to find and select useful videos directly.
  - imcritic 1y ago
    Parts of the article repeat other parts of that article. If you're saying that was done by a human, rather than by AI - then things are even worse.
BrandoElFollito 1y ago
I read this article two weeks ago (I would swear that it was on HN) and I was driving yesterday in the south of France, among plenty of wind turbines. I was recalling the article as I was driving and -- surprise -- a two-bladed one appeared suddenly (two, actually). This was the only time I saw two bladed wind turbines and could makr intelligent comments about why 3 and not 1 or 2 :) So thank you!

55 points by greedo 1y ago

TL,DR: three blades (1) are a good balance of torque against drag at different speeds, (2) help reduce unbalanced forces compared to two-blade turbines, and (3) provide visual balance, smoother motion, and quieter operation to improve community acceptance.

jefurii 1y ago

Is it related to automobile wheels always seeming to have odd-numbered spokes?

trenchpilgrim 1y ago
There are plenty of six spoke wheels?
potato3732842 1y ago
That has to do with the physics of harmonic vibration. It's not that you can't make even numbers of spokes balanced, it's just marginally easier to do odd numbers. Back in ye-olden days when things sucked there were more manufacturing benefits to it too but these days (this century) that doesn't really matter because even the sloppiest casting factory in china has their stuff figured out.

brudgers 1y ago

The actual content, https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0 https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0

throw0101c 1y ago
> https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0 https://youtu.be/pgqkti7yePk?si=stH2p71kNKy79WK0 PSA: the si, as well as pp, parameter is used for tracking. If possible consider trimming them when copy-pasting.
- brudgers 1y ago
  To the degree that kind of tracking significantly matters to you, there are alternatives that scale better and are more under your control. Personally, I doubt stripping the URL is going to meaningfully impact Google’s ability to track through Youtube. There are well paid, well funded, bonus motivated professionals who spend years throwing data science and computational expertise at the problem. They own search, the most popular browser, and handle a lot of DNS requests. Never mind that people tend to remain logged into their Youtube accounts, their Google accounts, and operate from the same handful of IP addresses through ISP’s who are happy to monetize data. Privacy theater is like security theater only less effective.
  - aendruk 1y ago
    It’s still a basic courtesy.
    - brudgers 1y ago
      BS. If you want to play make believe, that’s fine by me. However I don’t find it intellectually interesting.

miohtama 1y ago

There are companies working on two blade design, which has other benefits. You can try to get rid of balance problem with mechanical design and software: https://youtu.be/GbeFYLI8zYg?si=32wECCs05c4rRfs6 https://youtu.be/GbeFYLI8zYg?si=32wECCs05c4rRfs6

weinzierl 1y ago
We had the Growian two blade designs and its successor the Monopteros single blade design in the 80s. They were pretty famous back then and looked spectacular because of their sheer size and the unexpected asymmetry. Unfortunately they are almost forgotten now.
- yread 1y ago
  There were a few 0.5MW NedWind 40/500 just out of Medemblik, decommisioned in 2016 though
amelius 1y ago
Reminds me of Dyson, who makes zero-blade fans. https://www.dyson.com/air-treatment/fans-heaters https://www.dyson.com/air-treatment/fans-heaters
- 15155 1y ago
  These aren't zero-blade fans, they are normal multi-blade impellers that are piped into a duct.
- rammer 1y ago
  Yes and this reminds me of Dyson fans vs the 15 $ fans video https://www.youtube.com/watch?v=dS0oFmzU06g https://www.youtube.com/watch?v=dS0oFmzU06g
  - amelius 1y ago
    Air purification would be a useful feature in windfarms, though.

HPsquared 1y ago

In some ways, a single blade is the most efficient. Not very good mechanically though!

rammer 1y ago

[flagged]

Xss3 1y ago
Imagine thinking the fossil fuel industry and politics had nothing to do with this utter bullshit report. What a wonderful world you must live in, ignorance is bliss.
junto 1y ago
The 2015 Australian Senate “wind turbines” report wasn’t neutral fact-finding, it was a politically driven hit job. The inquiry was stacked with senators openly hostile to renewables (John Madigan, Bob Day, David Leyonhjelm, Chris Back). At least one (Back) had direct ties to the oil & gas industry via Shell. Others were aligned with think tanks and lobbying groups that consistently push fossil-fuel interests. The report’s Chapter 7 hand-wrings about “subsidies” and “market distortions” while ignoring wind’s documented benefits: lower wholesale prices, emissions abatement, and diversification. It selectively cites contested modeling, downplays contrary evidence, and then leaps to prescriptive recommendations, like cutting subsidies, tightening planning laws, and federal overrides, which just happen to chill wind investment. Even Labor senators filed a dissent, accusing the majority of misrepresenting evidence and overreaching. Meanwhile, fossil-fuel lobbyists have long had privileged access to Australian policymakers through donations, revolving-door appointments, and consultancies (McKinsey, IPA, Barton Deakin, etc.). This wasn’t about “evidence”, simply it was about protecting fossil incumbents and kneecapping a competitor. Sources: - APH: Senate wind report, Chapter 7 - https://www.aph.gov.au/parliamentary_business/committees/senate/wind_turbines/wind_turbines/Final%20Report/c07 https://www.aph.gov.au/parliamentary_business/committees/sen... - Labor dissenting report: https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Wind_Turbines/Wind_Turbines/Final_Report/d01 https://www.aph.gov.au/Parliamentary_Business/Committees/Sen... - RenewEconomy critique - Chris Back’s oil/gas background: https://reneweconomy.com.au/senate-wind-report-slammed-as-reckless-biased-attack-on-renewables-14968/ https://reneweconomy.com.au/senate-wind-report-slammed-as-re... - InfluenceMap on fossil fuel lobbying: https://influencemap.org/pressrelease/Unearthed-Australia-Statement-13560 https://influencemap.org/pressrelease/Unearthed-Australia-St... - Guardian on McKinsey fossil fuel conflict: https://www.theguardian.com/australia-news/2024/dec/06/mckinsey-consultancy-firm-australian-climate-change-policy-fossil-fuel-companies-ntwnfb https://www.theguardian.com/australia-news/2024/dec/06/mckin...

imcritic 1y ago

AI slop produced by someone that needed to meet word count criteria.

tentacleuno 1y ago
Perhaps that's an overly cynical take? It doesn't read like AI slop to me, more like an overview of the video. As someone who finds it hard to get solid answers online anymore, I found this article genuinely informative (though, of course, the video provides the most value.)
- em-bee 1y ago
  the point of the article/website appears to be to collect useful resources. as such it probably works better than trying to find and select useful videos directly.
- imcritic 1y ago
  Parts of the article repeat other parts of that article. If you're saying that was done by a human, rather than by AI - then things are even worse.

BrandoElFollito 1y ago

I read this article two weeks ago (I would swear that it was on HN) and I was driving yesterday in the south of France, among plenty of wind turbines. I was recalling the article as I was driving and -- surprise -- a two-bladed one appeared suddenly (two, actually). This was the only time I saw two bladed wind turbines and could makr intelligent comments about why 3 and not 1 or 2 :) So thank you!