Why Do Wind Turbines Have Three Blades?

Real Engineering
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There is a lot more to this subject than I have covered in this video, this is just the basics. I have used the Wind Turbine Handbook as my primary reference material, it covers pretty much everything you need to know about wind turbines. If you are studying this subject academically I highly recommend it. You buy it on amazon here: www.amazon.com/Wind-Energy-Handbook-Tony-Burton/dp/0470699752
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My Instagram: instagram.com/brianjamesmcmanus
Thank you to ruvid.net/u-Kristianpont
For allowing me to use his sound record of wind turbines
Stock footage sourced from videoblocks.com
Once again thanks to Bensound.com for the amazing royalty free music. This time I used Bensound - New Dawn
[1] Page 340 Wind Energy Handbook - Tony Burton

Published on


Apr 22, 2016




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Comments 1 372
Real Engineering
I plan to remake this video at some point. It's a really shallow explanation. I simply did not have the skill and experience to make a longer video when this was released. I could crank this video out in a single day now. The subject definitely deserves a more in-depth explanation.
Victor Gaiva
Victor Gaiva 14 days ago
Would love an update on this
ashish krishna
ashish krishna 2 months ago
You said it!
Michael Brink
Michael Brink 2 months ago
Not gonna lie I expected you to drop a skillshare promotion here, any time someone talks about learning I brace myself to hear about it.
Кирилл Хацько
why not talk about vertical turbines?
Yoshika Kehelpannala
Your explanations are not adequate. They sounds a little.
Speedy O
Speedy O 9 days ago
em wind turbines don't need and are not designed be next to houses so count that out
thebatmanover9000 13 days ago
This technology causes cancer!
sorry not you
sorry not you 5 days ago
Jason Jordan
Jason Jordan 25 days ago
what about smaller turbines for residential use? I live in central Kansas and I see the big ones up close but what design would work best around or on top of my farm house? I've always thought a different design would work better for closer to the ground wind generators. How does say a cylinder or cone shape compare if held in place with magnet bearings instead of traditional bearings? Use gravity to close openings if the speed becomes to great. I live where it's windy more days then not but I don't need a massive generator to power a 2 story farmhouse and a few out buildings.
McIntosh McDrone
McIntosh McDrone 25 days ago
If you have ever wanted to know how fast one of these wind turbines actually stand I made this video and it gives you a very close up look at that ruvid.net/video/video-vuZotgCqrUU.html
Justin M
Justin M 29 days ago
i always figured it was the same reason milking stools only have 3 legs
Him Bike
Him Bike Month ago
They have 3 blades to Kill more bald Eagles
Le Typ
Le Typ Month ago
Sadly no numbers to back the "conclusions"! so *vid in a nutshell* - more than 3 blades: not cost effective - less than 3 blades: too noisy
Flavius Nita
Flavius Nita Month ago
because it is not allowed with decimal point!
Mike Everett
Mike Everett Month ago
Good video, but hard to comprehend with that jungle music in the background. Would have liked to hear the upclose noise of the blades but the drum beat drowned it out.
Dragomir Ronilac
Rotational speed stability omitted... Shitty explanation
Slashed Nutts
Slashed Nutts Month ago
Here is some more modern day garbage. Wind Turbines , Wind Farms? The Kicker is if there is a wind they explode. They only work in a Breeze lol
manila goodmorning
was the video changed? i am a fan of this video. something was changed. i don't exactly know what...
Matt Denihan
Matt Denihan Month ago
Wow I’ve never seen a turbine explode like that
Tom Meyers
Tom Meyers Month ago
Why do illegal aliens have three blades?
Tony Idle
Tony Idle Month ago
Surprising then how many two-blade turbines are in use?
Brian newton
Brian newton Month ago
I didn't know that I wanted to know this information, until I saw the video pop up. Thanks for sharing.
Edward Haughney
Edward Haughney Month ago
Nice presentation. Right to the point.
brensasi Month ago
These damn things just on Vids give me Anxiety Man...they are so big they freak me out
nomercy0401 Month ago
Munich FX
Munich FX Month ago
Giants galore Sancho.
Kerry Galway
Kerry Galway Month ago
The only part you did not explain is the part where the cost of the manufacturing and the energy used to make are more than the turbine will produce in it's lifetime
RZU 147
RZU 147 Month ago
Ok? What are you talking about? What your saying makes no sense.
The V164 is owned and produced by MHI-Vestas not Vestas, which is a separate company from MHI-Vestas with a different product line
T K Month ago
Because they don't have four ?
Bunnie Miller
Bunnie Miller Month ago
BTW : the shorter 4 blade design would also help to eliminate any stress (tho not sure why "an even number of blades" creates stress that an odd number of blades doesn't from one blade being higher) caused since it would be that 10% (or whatever) of its blade length lower than the current model thus reducing both the chance of, as well as any effect of, wind speed that may occur due to the difference in height of the blades. All this keeping in mind that there are 2 ways to increase torque...longer "wrenches"...or MORE "short wrenches".
Bunnie Miller
Bunnie Miller Month ago
Well explained, but brings a question...what happens to cost, wind noise and power production if the 4 blade design has the blade length reduced by 10-15 percent? And a second also comes to mind reference the brake failure/turning to fast......why couldn't a 4 blade design be equipped with a way of turning two of the blades "backwards" when high winds are expected in order to have the blade spin counter each other, thus stopping their spin no matter HOW strong the wind gets and eliminating the possible damage that can (as seen in your video) happen??
Thanks! This was very easy to understand. I've always wondered why they don't use more blades, so as to increase the available torque, and thus be able to spin a higher capacity generator. I've never really considered what these machines cost, and that they need to be able to recover that cost in a reasonable amount of time.
I’m boutta E
I’m boutta E Month ago
Wind turbines are creepy af
Ed R
Ed R Month ago
Don't you know that liberals do everything wrong ? lol
Gazr Gazr
Gazr Gazr Month ago
Three leg stool better than four leg stool, two leg stool would not work ,think there is more to it than cost and weight, like balance etc, cheers.
Lord K Glencoe
Lord K Glencoe Month ago
This is by far the worst "real engineering" video. Bad maths. Bad science. Bad engineering analysis. I know that you can do better!
Splag Yetsi
Splag Yetsi Month ago
Good explanation
agsn 2 months ago
why not have circular ones with blades only at the edge
Stephen Carpenteri
Stephen Carpenteri 2 months ago
I have been very near turbines for years. They are very loud and disconcerting, making a loud "huffing" sound that is impossible to ignore and very disturbing. They kill thousands of birds that try to fly between the blades. Also, owners of these turbines tell me that they have an electric motor that starts the blades but the amount of electricity generated in a day is not enough to replenish the starter. Not a good idea!
RZU 147
RZU 147 Month ago
Buildings kill birds. Who could have thought. Birds a dumb. IF they made less then they need WHY IN HELL DO WE BUILD THEM? AND WHY DO WE GET POWER FROM THEM?#!
panlomito 2 months ago
Waarom überhaupt windturbines... omwonenden worden helemaal gestoord van het geluid en slagschaduw van de wieken, en de windturbines maken onze energievoorziening onbetrouwbaar en onbetaalbaar voor de consument. Doe mij maar kernenergie!
kingz8ter 2 months ago
Why not a spiral spring design?
Take a Break
Take a Break 2 months ago
put the wind turbine in your ass lmao.
sagar panchal
sagar panchal 2 months ago
I think you didnt get the main and major point... Comparison between 2 and 3blades turbine.... Wind speed increases with height and if you use 2 blade turbine then you should have one device to balance blades... This phenomenon doesnt happen in 3 blade turbine.
Shahbaz Khan
Shahbaz Khan 2 months ago
Does wind have to blow in a specific direction for these to work or the design lends itself to work no matter which way the wind is blowing?
RZU 147
RZU 147 Month ago
You turn the thing into the wind.
John Mann
John Mann 2 months ago
Power an entire town... bahahaha!
Jay Dee
Jay Dee 2 months ago
@2:20 ... You're welcome...!!
Ricardo A. Bastianon
En mi libro Energía del Viento y Diseño de Turbinas Eólicas se explica en detalle porqué las turbinas tienen una, dos, tres o más palas con las ventajas e inconvenientes de cada una. bastianon2001@yahoo.com.ar
Anthony Ivanov
Anthony Ivanov 2 months ago
:D Stfuuuuuuuuuuup
adriaan van harrick
adriaan van harrick 2 months ago
It just occurred to me, that there is something distinctly off with that theory that 3 blades would help reduce the stresses that occur from one blade getting no wind when it passes the pole, or mast or tower or whatever it is and its name is, at the lowest point of the circle these blades describe, and that the idea that a 3-bladed design would involve a reduction in the distortion of balance (and with that extra vibrations and extra stresses that play onto several parts) simply can't be right. When you think about it, with a 3-blade setup, there are TWO blades getting full wind whilst one gets none each time, so now 2 put up full force against that one blade that produces less our none for a short while, instead of the one active blade that is oriented oppositive of the one that momentarily is inacive each time as it happens in the 2-blade design. The relative stresses are theoretically up to twice as big! I think it would be fair to conclude: 1 it may have got more to do with other variations and effects that might cause vibration, trembling and lack of balance, such as the fact that even over a distance of dozens of meters the force/speed of the wind might vary; 2 it might have got more to do with the actual surface of the blades (seems that although too long blades come with the problem of too high tip speed in up to several hundred kilometers/hour, blades that are constructed in a wider fashion like was done with the old (old-fashioned) wooden windmills, for some reason ALSO again is not favored by designers); 3 to overcome or at least significantly reduce the stress caused by the unbalance coming from one blade putting up no counter force for a short while each time, you would at least need 5 blades, and preferably even seven. In a setup that sports 5 blades, the blade that momentarily stops producing force (and therewith counterweight relative to the other blade or blades) is always accompanied by TWO other blades that ARE ACTIVE AT ITS OWN SIDE (halve if you will) of the axis so a construction like this puts up most of the oppositive forces that out takes to balance the two remaining active blades that are on the other side of the central point of rotation. As opposed to there being two active blades OPPOSITE to it on the axis and NONE on its own side in the 3-blade setup. This however gradually becomes much more difficult to mount to the central axis of the thing, supposedly might be pricier as there is some loss simply related to the scaling difference versus the effective surface created. And, ALL blades have a small part, near where they are mounted, where they catch little or no wind anyway, as the generator housing also blocks the wind
Adrian G
Adrian G 2 months ago
These statements just don't stack up, i was thinking. Then i saw others' commenting about the same thing. The video should be pulled. Sorry to say it but its a hopeless attempt at explaining the issues. Plus it makes one wonder if the author's other videos are based on fact and actual engineering, and worth anything. This video does him a disservice - it realy shouldn't be up here.
RZU 147
RZU 147 Month ago
Whats the problem?
raghavendra babu
raghavendra babu 2 months ago
No useful information. No explanation. Wasted my precious time😔
malcolm nicholls
malcolm nicholls 2 months ago
Well I liked it. Thanks.
jeroen waterschoot
jeroen waterschoot 2 months ago
So they can KILL more birds in one go
Aurobindo Ghosh
Aurobindo Ghosh 2 months ago
maybe because the three blade setup looks good
tiger TIGER
tiger TIGER 2 months ago
AstronautK3nny 2 months ago
Make them lower geared if its too fast with more blades
Shubham MishRA
Shubham MishRA 2 months ago
You are truly good in explaining contents 👍.
YouSurf 2 months ago
Wind turbines should be dedicated to either produce hydrogen, to then be shipped and used in fuel cells for clean production of energy when you need it, or should maybe charge Iron Flow batteries where a fleet of trucks could haul them around where the energy is needed cause people should not live NEAR such wind farms. Really.
YouSurf 2 months ago
the 3 blade safety failed devastatingly due to brake failure... so the sunk cost is now total loss at that point. SO... may be safer and more longevity to have a slower moving 5 blade setup, or 4... may be less chance for brake to fail and if fails, maybe slower rotation will not go outta control unless serious high wind, which one could manually lock it out with a signal sent prior to wind event rather than automatic braking. .
YouSurf 2 months ago
they have three blades to ensure they produce a subsonic vibration at a frequency that drives people INSANE!!!!!!!!
Ultima Thule
Ultima Thule 2 months ago
Totally WRONG explanation. This video should be cancelled.
Mike Smith
Mike Smith 2 months ago
Engineers are dumb and cannot count past 3 I guess....... why 90% are a waste ot time and energy and never balance the energy books. The new cock sucker turbines west of my town sometime go days and not even do one blade revolution, let alone run in 37kph min. wind speed to make any power.
CaseOfThe Sniffles
CaseOfThe Sniffles 2 months ago
did you even watch the video retard?
KnightOfGaea 2 months ago
Whatever happened to helixical and double helix wind turbines?
Hi Bye
Hi Bye 2 months ago
I like this Irish guy He’s a smart Irish person Not very Irish
Tahoe Jones
Tahoe Jones 2 months ago
If you adjusted the angle of the blades, the 'sweet spot' could be a constant. Not rocket science.
Philip Price
Philip Price 2 months ago
But why not this? ruvid.net/video/video-I4JhkzmE9ug.html
adriaan van harrick
adriaan van harrick 2 months ago
tho in real life you for sure hear the blades woosh by when you are near such a giant wind turbine, the recording we get to hear here only contains audible sound from the gear box inside, that steps up the amount of rotations before it drives the generator, and that can be very loud (in these monster size mills)
William J.
William J. 2 months ago
Why do chicken coups have two doors? If they had four doors, they’d be chicken sedans! I’ll show myself out.....
Flambo One
Flambo One 2 months ago
Because they do not want copy the Dutch. And also four is one too many.
Chet Chamberlain
Chet Chamberlain 2 months ago
I thought additional blades would be better. The explanation for 4 blades not being cost efficient was quite shallow. If we’re making 12 blades, it would be cheaper to only make and anchor 3 bases rather than 4 bases. Obviously there’s more to it.
Ug0tmi1k 2 months ago
Civil engineering student here. Once tested different turbine configurations with different NACA airfoil shapes for a class. I was always taught that 4 blades would give you more power than a 3 blade turbine, but only marginally. Adding an extra blade at that size means you're adding on a huge amount of mass, so the extra energy produced is surprisingly small. Thus, if you did a simple cost-benefit analysis, you'd see that the cost of adding a single blade, which is massive, is not warranted by the amount of energy produced in the turbine's lifespan. Two blades, if I recall correctly, had a very high rate of failure. Thus three blades was the Goldilocks of all designs Also, the video mentioned "centrifugal force", and I'd always been under the impression that there was no such thing. I remember being told there's centripetal force, but centrifugal force was something that non-physics people made up. Was I the only one taught this? Is this notion wrong?
wanderley apparecido Vieira
More blades more drag,need more wind speed ,so more power to move it .
Gabriel Freitas
Gabriel Freitas 3 months ago
avfuels 3 months ago
Why Do Wind Turbines Have Three Blades? To kill more birds.
Rajat Poonia
Rajat Poonia 3 months ago
I have better reason for this , net centrifugal force of two blades cancel out the centrifugal force of third blade
赵是 3 months ago
You keep doing videos informative like this your channel goes down toilet.
paulla smith
paulla smith 3 months ago
One bladed fans are all that's needed. It just wobbles at high speed.
paulla smith
paulla smith 3 months ago
To determine what high speed is; install a stationary arm about 5 foot length perpendicular to the support post, near the top. Tie an eight foot long rope around the far end of the extended arm, and tie a large bell to the other end of the rope and let it hang there. If the bell begins ringing , the speed for the one blader is too fast.
Mohna Khan
Mohna Khan 3 months ago
Very Poor & Unmathematical Explanation 😡😡😡😡 You really raped the topic...
Michael Nablo
Michael Nablo 3 months ago
Coz it's not two😎
Astig Naepal
Astig Naepal 3 months ago
what is all these stats that says these wind turbines are a scam?
John Campbell
John Campbell 3 months ago
3 is a magic number in physics. 3 phase wiring is the most efficient way to transmit power. 3 phase motors are self starting. 2 phase motors would not be self starting. 4 phase wiring would just be too expensive for copper costs.
Bartok Loky
Bartok Loky 3 months ago
pseudo-scientific bullshit , the only reason is econometric. cost vs efficiency. the optimal value is currently at 3 blades. the gain you get from adding one more blade decreases with the number of blades, while the extra cost is generally the same.
Paul Keith
Paul Keith 3 months ago
Because they are very expensive- and three is the minimum to run effectively. Five blades would be more efficient- but would substantially increase manufacturing and maintenance costs. All successful concepts are an amalgam of engineering efficiency and cost.
Ali Z Syed
Ali Z Syed 3 months ago
wait, then why do plane propellers have two blades
Honestmicky 3 months ago
Excellent video, thanks for posting, much appreciated : )
Casey Klahn
Casey Klahn 3 months ago
Proponents of wind power think nothing of cost efficiency. If they did, they wouldn't put the money into wind, they'd put it onto hydro-electric or shale oil. It took me a while to find the data, but it turns out that all of the expensive wind systems in the Central Washington and Columbia Gorge areas, if finally implemented in full, would equal the output of one hydro electric generator (Grand Coulee Dam has 33). "Wind" is an enviro overreach, but who cares as long as we make renewables mandatory (except hydro, the best one...because: liberal!) ? Oh, I figured out how to solve global warming. Implement Marx in total. Peace/ out.
R Rad
R Rad 3 months ago
Wow! Great analysis!
Truth To Power
Truth To Power 3 months ago
Big energy is running a big smear campaign on wind energy. Like the campaign they ran to protect leaded gas. Trillions of infrastructure will be stranded. USA USA USA! 🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸
Joran Heij
Joran Heij 3 months ago
please say 2:22 is not in the dutch xD
fjandgoob 3 months ago
the use of only 3 blades is an economical issue as 4 blades would put a windmill at a MORE COSTLY endeavor, only to be passed to the taxpayer.
Dennis 3 months ago
Free advertising for Mercedes?
Korisniknovi 3 months ago
So, essentially, you're making this stuff up as you go along, right? interestingengineering.com/the-scientific-reason-why-wind-turbines-have-3-blades Literally the first result when one googles "Why Do Wind Turbines Have Three Blades" and completely the opposite of your explanation.
thearchitect27 3 months ago
How about the concept of strength versus stability as applied to the three-bladed wind turbine system? Don't three blades make the wind turbine that much more effective against the heavy wind loads, which can be quite destructive, as depicted at the end of your clip? Thanks mate! Happy 2019!
daffidavit 3 months ago
For the same reasons, some single engine airplanes have three blades instead of two. Two blades are more efficient. But three blades are shorter to produce a similar amount of thrust. BTW, I understand from a man whose company uses drones to inspect cracks in the windmill blades that each blade costs about one million per blade.
Marie BCFHS 3 months ago
also 3 blades look more elegant
Christopher Van
Christopher Van 3 months ago
So that they can kill the maximum number of birds.
Random autist
Random autist 3 months ago
infinite energy source idea: what if we build a bigass wind turbine that powers a giant ass wind generator that blows at the turbine?
nahmanini sithole
nahmanini sithole 3 months ago
The three blade design is obviously to smack the most birds.
vladimir ikic
vladimir ikic 3 months ago
Because 2 wouldnt work and 3 is most cheap to work. And modern turbines are massivly expensive. So that's why 3?
korelly 3 months ago
I read somewhere that the power of the wind turbine does not depend on the number of blades, but on the surface covered by the blades. That would explain why more blades does not mean more power.
clockwork org
clockwork org 3 months ago
The real question is .. why do I have 2 balls ?
Alan Strong
Alan Strong 4 months ago
Would be delighted to have a residential version of that.
Keith Lauder Jr
Keith Lauder Jr 4 months ago
Wind Power = Idiot Power Modern turbines will never replace power and resources it took to create. Big Scam
Nathan Frey
Nathan Frey 4 months ago
Why do they have 3 blades? Is it because they have more than 2 and less than 4?
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