Just how long ARE wind-turbine blades?

[Wlfman13]

Since this is the General Discussion forum, I figured this question is fair game.

My car is at the bottom of the photo. The blades were definitely spinning!

So, if anyone can answer two questions, I would be very grateful:

1. How long are those blades?
2. How fast are those blades turning? (The video doesn't do the "whooshing" sound justice.). I now know how eagles die when they are hit by those things... (I just learned that I can't post video...)

I have to admit, my initial plan was to capture video at the very bottom of the blade travel, but I was completely fine where I was, and suddenly thought my camera angle would work out better. Call it chickening out, but the fact that I have a family suddenly became very important, and if I make the national news, I'd rather it not be because I won a Darwin Award.

That "cube" at the bottom of the photo? I estimate that it is 8 feet tall, and the posts around it are 5 feet tall. The box had "34,500 Volts" painted on it!

Lastly, no wind-turbines were harmed during the filming. There was no gate, and the only sign said, "Speed Limit 15MPH".

-Wlf

[Ikeo74]

https://en.wikipedia.org/wiki/Wind_t...n#Turbine_size

Wikipedia .org says and average tower is 65 meters high or a little more than 195 feet
each blade runs from smallest 40 meters or 120 feet to largest is 50 meters or 150 feet
the ones in your picture are probably 150 feet

The ones over water are larger.

[yqtszhj]

I know when I’ve seen them being towed by a tractor trailer that the trailer seems to go on for ever.

[Ken L]

Did a quick google search on the speeds. I knew it was fast, but I didn't know just how fast. WOW

The B75 turbine blade itself is 75 meters long, while the entire rotor assembly measures 154 meters in diameter. As it spins, the blades cover an area of 18,600 square meters—that's roughly two and a half soccer fields—at a brisk

80 meters per second

, or

180 MPH

at the tips

[CPTKILLER]

Correct, they vary in size.

[Bawanna]

Must be a full time job for a bunch of guys just to keep the bearings greased in one of those things.

I don't do well with heights so reckon it wouldn't be a job for me.

[Ikeo74]

I am only guessing but the rotation speed of the center hub looks like less than 60 RPM. So lubrication should not be a problem. I could be wrong but watching the blades turn from a distance, it takes a while for them to make 1 revolution. The tip of the blade is moving faster because of the giant circle it travels around.

[ltxi]

I am only guessing but the rotation speed of the center hub looks like less than 60 RPM. So lubrication should not be a problem. I could be wrong but watching the blades turn from a distance, it takes a while for them to make 1 revolution. The tip of the blade is moving faster because of the giant circle it travels around.

Point of order: Rotational speed is the same at any point along the rotating assembly.

[AIRret]

The left wants it both ways…..wind turbines mean good green energy… but what about the birds, especially when they are migrating.

Pipe line, no, no, no, you have to research wildlife migration and make sure there is no interference!

They can't have it both ways….it makes my head spin, and I'm not a turbine.

[Ikeo74]

Point of order: Rotational speed is the same at any point along the rotating assembly.

IT is still less than 60 rpm. Distance traveled in 1 revolution depends on the length of the blade.

Rotation Speed is less than 60 rpm. IMO

From the article the hub rotation is even less than I guessed. Hub turns at 15 to 20 RPM

Gearbox[edit]

In conventional wind turbines, the blades spin a shaft that is connected through a gearbox to the generator. The gearbox converts the turning speed of the blades 15 to 20 rotations per minute for a large, one-megawatt turbine into the faster 1,800 revolutions per minute that the generator needs to generate electricity.^[12] Analysts from GlobalData estimate that gearbox market grows from $3.2bn in 2006 to $6.9bn in 2011, and to $8.1bn by 2020. Market leaders were Winergy in 2011.^[13] The use of magnetic gearboxes has also been explored as a way of reducing wind turbine maintenance costs.^[14]