Wind Turbines and Skydiving!

[Birdguy 0]

Hello All;

I am new here and have only 10 Jumps sofar on my Student Progression. I was wondering though if any Dropzones out there have had to Deal with Wind Turbines near their DZ's.
I ask this because they are thinking of putting a Wind Farm 4000' from my home DZ. The Turbulance that these can put out, potentially can be Hazerdous to Parchutists.Not to mention the Jump Planes Taking off and Landing.
Yes we all like the Idea of Renwable and Clean Energy, but it shouldn't risk peoples Lives
Any first hand knowledge on this would be Greatly Appreciated.

Cheer's Garth

[piisfish 135]

what do you know about turbulence caused by a wind turbine ?
seriously, I can't imagine that the turbulence is much greater than the hangar in which your plane sleeps...
the wind turbines do not create wind AFAIK.. they use the existing wind to create electricity... But what do I know about wind turbines ?? ...

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[howardwhite 3]

Ask the folks at Byron, CA. They seem to live with lots of wind turbines.
(Attached picture stolen from Flickr.)

HW

[TrickyDicky 0]

There is a DZ in the UK that has a couple of wind turbines about a mile from the DZ (I think they're 2-300' tall). no problems at all. What is a problem was when the factory on the edge of the DZ (its next to a village and industrial estate) tried to erect one, in reality for tax purposes. The DZ managed to get the planning permission rejected on the grounds of closing the DZ because of danger to aircraft and skydivers. But that was within 200' of the landing area.

I dont think 4000' is going to cause a problem. Thats between half a mile and a mile away.

UK Skydiver for all your UK skydiving needs.

[virgin-burner 1]

we have a company that produces fireworks right over the road from our dz. they sometimes test during the day. that worries me much more than any wind turbine ever would..

“Some may never live, but the crazy never die.”
-Hunter S. Thompson
"No. Try not. Do... or do not. There is no try."
-Yoda

[JohnRich 4]

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I dont think 4000' is going to cause a problem. Thats between half a mile and a mile away.

Think of it this way: 4,000' is about the length of a runway.

How often do jumpers have spots that land them at the wrong end of a runway? Not often, but it happens.

Sooner or later, when the winds are from the wrong direction, and someone gets a bad spot, they'll end up in those turbines.

Are these going to be built straight off the end of a runway, where it will create a hazard to take-offs and landings? I would think the FAA would have something to say about that - they regulate such things.

[riggerrob 558]

Yes, those wind mills near Byron and California City are a real nuisance!
Every time they crank up those wind mills, it gets too windy to skydive.

Re-phrase ... young guys get dragged through cacti while old tandem masters enjoy the entertainment from the balcony!

[billvon 2,380]

In terms of turbulence, they are akin to trees, not as bad as buildings, per pilots who have flown near them. (After all, wind does pass through them fairly effectively.)

There's a rule called the 10:1 rule that's generally good to follow. It basically means that if something is 100 feet tall, land at least 1000 feet from it to minimize turbulence. Thus, as long as the top of the rotor was less than 400 feet tall, and you land 4000 feet away - you _should_ be OK.

[kelpdiver 2]

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Ask the folks at Byron, CA. They seem to live with lots of wind turbines.
(Attached picture stolen from Flickr.)

HW

Those windmills are pretty far away. The main problem is the reason the mills are installed there at all - lots of wind holds.

A bit north at Skydance, the LZ is adjacent to a shooting range, and often the pattern takes you right overhead.

4000' isn't too far away, but unless this wind farm is highly elongated, it shouldn't be hard to have a jump run that results in no intersection. Obviously it becomes a don't go zone, like power lines.

[jose9878 0]

The windmills are a good 2.5 miles from the dropzone at Byron. They are not an issue unless Ego is spotting. It is windy, 30 mph+ winds at times but we get used to it. I stop jumping when the hangar doors start rattling, that's 28 - 35 mph winds. 4000' is a bit short of a mile, I wouldn't think they should be a factor unless you get target fixation.

[ficus 0]

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(Attached picture stolen from Flickr.)

Damn that's a sexy jumpsuit.

[stratostar 5]

It just looks better then normal because everything else around it is so UGLY!

you can't pay for kids schoolin' with love of skydiving! ~ Airtwardo

[pchapman 261]

I'm not sure about the whole issue.

At the original poster's DZ (mine too), the wind turbines would go up on a small hill that's right under the normal aircraft circuit, and would be close to directly upwind of the DZ for the most common wind direction.

The first issue becomes 300+ ft turbines on a 200 ft hill when the aircraft is on the crosswind climbing leg, flying not a whole lot higher than that. So it becomes an obstacle as well as a potential turbulence source during the climb. Taking the circuit in the other direction puts it closer to a small town. Circuits could be changed but it would be awkward.

The airfield is a small private airfield. While it is Registered and in the airport directory, it won't have the same legal protection against obstacles as a full Certified airport with IFR traffic might have.

Looking at Google Maps, it seems the nearest edge of the turbine field would be on the order of 4000' from the end of the DZ runway -- so it would be another 1500' or so to the main landing area.
(Putting it in skydiver terms, a long tandem spot could go right over the planned turbine field, but not a normal jumper spot.)

As for turbines in general:
One wind turbine study showed velocity deficits (reductions in wind speed) behind large farms extending 5 to 20 km before the wind speed returned to the original level. So the effect of turbines can extend a long way. However, we are talking about reductions in wind speed that might be 15% near the turbines, and 2% 5+ km way.

So while the effect of turbines can extend surprisingly far, the question then becomes whether those effects are significant for flight. I wonder how far any significant turbulence will extend behind turbines. There will be vortexes coming off the blade tips for example, drifting downwind. I don't know whether they would last as long as they can behind large aircraft with high speeds and high wing loadings. If vortexes did persist for a couple minutes at strong but jumpable wind speeds, they could go 4000'. Still, I'm guessing the major effects wouldn't go nearly that far. But I have no real evidence either way.

I'd really like to know more about turbulence downstream of wind turbines.

There was one parachuting fatality related to wind turbines, when a first jump student in Germany was struck and killed by a turbine blade in 2000, jumping in strong upper wind conditions. Sounds like they were a typical lost first jump static line student, for they ended up 3+ km from the DZ. It was on an island where pretty much every farm field has a turbine in it. While this an example of turbine hazards, hazards also exist from plain old buildings, powerlines, and trees.

[Birdguy 0]

Thanks to all that have replied. I don't know much on Prop Wash other than if you are standing behind a Harvard you may loose your footing as well as your Hat!
I am all for Green Energy and I am active Environmentally. Sometimes us with Good intentions on protecting the Planet should have to think twice before we cause an adverse effect on others.I was all for these Turbines before I started hearing about the effects of how far the Wash could Travel and the possible effect on Canopies as well as Jump Planes.
Hopefully this will be resolved quickly and effectively.

Once again thanks for your input it has been Helpful and I will try keep you informed on the Outcome!

Cheer's Garth

[Elisha 1]

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(Attached picture stolen from Flickr.)

Damn that's a sexy jumpsuit.

Oh, it's not the jumpsuit that's sexy.

[Armour666 0]

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what do you know about turbulence caused by a wind turbine ?
seriously, I can't imagine that the turbulence is much greater than the hangar in which your plane sleeps...
the wind turbines do not create wind AFAIK.. they use the existing wind to create electricity... But what do I know about wind turbines ?? ...

Turbulence off buildings is dirty and dissipates rapidly and close proximity to the ground disrupts them. The 10-1 rule fits well for static objects. The issue is wind turbines are located 2-300 meters off the ground and they are getting large, really large. The blades are designed to be very efficient and the surface area of the blades is equivalent of many airliner wings. With that in mind ask a small plane pilot or ATC what the flight separation behind a heavy is. Now you can start to see the potential problem is.

A large efficient wing X 3 X the number of wind generators located 100-300 meters of the ground creating clean efficient vortexes that have no obstructions.

The studies I have looked at for this issue almost all studies focus on Wind farm efficiency and the effects of the vortexes in the immediate area and how it impacts tower placement but none to date have looked in-depth at the long distance effects of the vortexes and their strengths.

The study Peter mentions was done by Risø National Laboratory using Synthetic aperture radar on ERS-2 and ENVISAT Satellites looking at the sites at Horns Rev and Nysted wind Farm off the coast of Denmark. This is the only study and it is limited in over all scope that looks at wind farm effects over a greater distance.

SO this one time at band camp.....

"Of all the things I've lost I miss my mind the most."

[MotherGoose 0]

DON'T FORGET ABOUT THE POOR BATS. What's next? Exploding skydivers?

Wind turbines make bat lungs explode

* 17:00 25 August 2008
* NewScientist.com news service
* Catherine Brahic


"Beware: exploding lungs" is not a sign one would expect to see at a wind farm. But a new study suggests this is the main reason bats die in large numbers around wind turbines.

The risk that wind turbines pose to birds is well known and has dogged debates over wind energy. In fact, several studies have suggested the risk to bats is greater. In May 2007, the US National Research Council published the results of a survey of US wind farms showing that two bat species accounted for 60% of winged animals killed. Migrating birds, meanwhile, appear to steer clear of the turbines.

Why bats - who echolocate moving objects - are killed by turbines has remained a mystery until now. The research council thought the high-frequency noise from the turbines' gears and blades could be disrupting the bats' echolocation systems.

In fact, a new study shows that the moving blades cause a drop in pressure that makes the delicate lungs of bats suddenly expand, bursting the tissue's blood vessels. This is known as a barotrauma, and is well-known to scuba divers.

"While searching for bat carcasses under wind turbines, we noticed that many of the carcasses had no external injuries or no visible cause of death," says Erin Baerwald of the University of Calgary in Canada.
Internal injuries

Baerwald and colleagues collected 188 dead bats from wind farms across southern Alberta, and determined their cause of death. They found that 90% of the bats had signs of internal haemorrhaging, but only half showed any signs of direct contact with the windmill blades. Only 8% had signs of external injuries but no internal injuries.

The movement of wind-turbine blades creates a vortex of lower air pressure around the blade tips similar to the vortex at the tip of aeroplane wings. Others have suggested that this could be lethal to bats, but until now no-one had carried out necropsies to verify the theory.

Baerwald and her colleagues believe that birds do not suffer the same fate as bats - the majority of birds are killed by direct contact with the blades - because their lungs are more rigid than those of bats and therefore more resistant to sudden changes in pressure.

Bats eat nocturnal insects including agricultural pests, so if wind turbines affected their population levels, this could affect the rest of the local ecosystems. And the effects could even be international. "The species being killed are migrants," says Baerwald. "If bats are killed in Canada that could have consequences for ecosystems as far away as Mexico."
Windy day

One solution could be to increase the minimum wind speed needed to set the blades in motion. Most bats are more active in low wind.

The study was funded by a number of bat conservation groups together with energy companies with a financial interest in wind energy, such as Shell Canada and Alberta Wind Energy.

Journal reference: Current Biology (vol 18 p R696)

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