The Ghost in the Gearbox: How White Etch Cracks Haunt the Wind Industry
Lubrication Explained
If you spend as much time on YouTube as I do, I am sure you have seen numerous videos of wind turbines catching fire, falling apart or otherwise failing. This guy gives us a good explanation of the root cause of these failures. The key point is that these bearings fail without any warning, no indication that there is anything wrong, and then boom! All of sudden the bearing fails and the whole thing disintegrates. The thing he doesn't talk about is just how big the loads are in wind turbine bearings and how much stress there is. I look at those things with those hundred foot long blades and I'm thinking that the loads on the bearings have got to be out of this world. So maybe we are actually going to learn something useful from this whole wind turbine / green-energy debacle.
Brian Potter points to a story on Clean Technica. They seem to be planning on deploying these things in the jet stream, umpteen thousands of feet in the air.
I like this picture because it shows just how big a wind turbine is. It's hard to show how big they are because there is never anything around them that you can use for comparison. A picture with a person doesn't work because by the time you zoom out far enough to get the whole turbine in the picture, the person is reduced to a single pixel, which doesn't really help.
Some people think this picture indicates that wind turbines are stupid. Time will tell. The rapid proliferation of wind turbines is due to government policy in the form of tax benefits. It's kind of like ethanol (from corn) that way. It might not be the most economical way to produce electricity, but it's a worthwhile experiment. Even with the vast numbers of them being installed, they still don't produce a noticeable percentage of the electricity we use.
The problem with icing might be due to the get-er-done mindset which ignored the possibility of ice being a problem. Or maybe they considered it, and de-icing by helicopter is the most economical solution. Or maybe it's a freak occurrence that wasn't worth worrying about, until it was.
Small
F2A World Record - Control-line model aircraft speed.
Raddaddy watanen comments:
Some facts for you fellas: Only one-inboard wing, as the drag of the 2 lines are the biggest drag factor. One line is forbidden by the rules (monoline) also longer than 1 m wings outruled. Engine turns at about 40.000 rpm so the two blade prop is ineffective ( other blade falls in the slipstream of the other). The one blade prop tip travels in excess of sound of speed (Tip speed is +1MACH!) and the counterweight is inside the spinner. The 2,5cc glo engine delivers more than 2,5 horsepower. so if it would be a 2,5 litre car engine, the power would be 2500 horsepower. Now you MAY understand these "toys" are actually VERY HIGH TECH scale racers...
Could the engine really be turning 40,000 RPM? That's pretty fast. It is very small. I ran the numbers just to see, and it seems reasonable. 800 MPH is a little more than Mach 1.
I had a couple of control-line model aircraft when I was a kid. Only flew them once or twice. Not sure why. Perhaps it was too big a production for such a small person.
MidAmerican Energy Company - From the Ground Up: Building our energy future, one turbine at a time
I don't know that I like these giant wind turbines. It's all very nice that we're getting electricity for 'free', but that is a big, expensive piece of equipment. You would need to generate a great deal of electricity to pay for such a big machine. I supposed they work out eventually, I mean once you set them up they don't require a great deal of attention, so in ten or twenty or a hundred years they should pay for themselves, assuming of course they generate enough electricity to pay for the interest on the loan. Interest rates are low these days, so maybe now is a good time to build them.
A second problem is you are still getting your electricity from a giant soulless corporation and you are going to be subject to all the problems you get with that arrangement, like blackouts and brownouts and getting your power shut off because you failed to pay your bill. On the other hand, all you have to do is pay your bill. No fussing with generators and wind storms and construction contractors.
The last problem is birds. There was some noise about birds getting killed by older, smaller wind turbines. Then we got these big ones and people said that it wouldn't be as big a problem because look how slow they are turning. Yes, the RPM's are low, but the speed of the tips of the blades is still very high, maybe even higher than the old ones, so I could see how there could still be a problem. But maybe all the stupid birds have been killed off so now we only have birds who are smart enough to avoid these things.
I was looking at the chili factory in Fort Madison because I thought it belonged to Hormel, but it turns out that it belongs to Pinnacle Foods. But I'm looking at the map and on the other side of the main railroad line I see all these toothpick like things lying on the ground and I wonder what the devil could they be. Telephone poles, maybe? No! They are wind turbine blades. This here is the Siemens factory.
Dennis sent me this link about a week ago. It's kind of intriguing.
These guys are trying to outrun the wind, that is, they are going in the same direction as the wind, only faster. There is a wind vane and a anemometer mounted on top of the chase car. Notice that the vane is pointing toward the back when they start out, but that after they get up to speed it is pointing the opposite way: towards the front indicating that they are going into the wind. The wind hasn't changed direction, only their velocity has.
The cart has no engine, it is powered solely by the wind. The wheels are connected to the propeller through gears.
I read some of the stories, but nowhere did I find a clear explanation of how it works. I've been stewing about it, and I've come up with an explanation of sorts. It may not be the best, but it's all I've got so far, so I thought I would throw it out there and see if it floats.
First of all, you need to realize that the propeller is not working as a turbine. If it were then the wind would turn the propeller and the propeller would turn the wheels. That would work only as long as the wind was blowing faster than the cart, and that is not what they are trying to do. If you look at the way the propeller blades are pitched and the way the prop is turning when it first starts out you will see that the propeller is turning the wrong way for it to act like a turbine.
So the propeller is turning into the air as the cart moves forward. Pushing the cart forward in still air would take very little effort. The cart is light, the wheels have low rolling resistance, kind of like high pressure bicycle tires, and the propeller is basically freewheeling through the air. It is screwing through the air in the same direction and at roughly the same rate as the cart is moving over the ground. A guy could probably push it along at 5 or 10 MPH without too much difficulty. How long he could keep it up would depend on how fit he was, but that's really beside the point.
If the propeller was not turning, i.e. it was locked in place, it would take considerably more effort to push the cart along because you would be trying to push this propeller through the air.
With the wind blowing, it is going to be pushing on those propeller blades as if they weren't turning, but because the blades are turning as though they were in still air, but now we have wind pushing them, so now we are moving 5 or 10 MPH faster than the wind.
With no wind, there is virtually no force on the propeller blades, no matter what speed you are going. With the wind blowing, we've got the force of wind pushing on those propeller blades, and that is what is going to make it go. The only thing holding this thing back is friction, friction from the wheels, the bearings, and even the air. It is going faster than the air.
Talking to a Bob, a older guy that mows lawns in his spare time. A big time Cubs fan in a town where your either a Cubby or Cardinals fan.
Bob works at Pinnacle Foods, which everyone calls Armour, recalling its' earlier owner.
He receives 2,000 pound, pallets of frozen deboned beef and pork. Placed into a large pot heated with spices and other ingredients, voila Chili, Beef stew or something else.
Bob says he has never seen it so busy. They are running 12 hour shifts 7 days a week. The weak economy is good for them, people are buying up cheap food.
Pinnacle is owned by the Blackstone Group which is traded as BX on the NYSE.
Theoretically speaking, wind turbines seem like a pretty good idea. Free power, or at least power without any fuel. But each of these turbines cost around $2.5 million installed. How long is it going to take to pay that back? Evidently some people think the payback time is reasonable.
And then there's the feeling I get when I see these things. Mostly they are installed in open fields, and it just strikes me that there is something wrong with sticking these enormous spindly structures in the middle of the fields. Maybe it's just my attraction to "wide open spaces", and there is no real good basis for my feelings.
And then there are the birds. I came across one story that claimed most bird strikes happened with older, smaller and faster spinning turbines, and since the newer turbines spin slower, it shouldn't be a problem. Well, the rotational speed of these turbines is much lower, taking maybe six seconds to complete a revolution, but the diameter is much larger and so the linear velocity at the outer ends of the blades is much higher. For a turbine with 130 foot long blades, turning at ten RPM (six seconds per revolution), the linear velocity at the tip of the blade is over 90 MPH.
