Digital Photography

by Paul Farrier

Sunday, October 7, 2007

180 MPH

On our way to Seneca Rocks one morning last week, we stopped on top of this mountain in West Virginia on US 219 to check out these wind driven generators.

The generator sits atop this pole. How high? I don't know. And not much of a breeze forces the these giant propellers to turn. How long are these propellers? 150' from tip to center.

There's not much there in the picture to indicate the relative size and show just how big these things are except for a truck parked near the base.

I've seen propellers like these being shipped westward on I-70, e x t r a l o n g loads on extended trailers. They dwarf the tractor that is pulling the load.

Anyway - standing on top of the mountain with a couple of engineers - they marvel at this creation. Ken Parks, an engineer formerly with GE who is familiar with wind turbines, said the diameter of the spinning blades is approximately 300'. David Barnes, an engineer visiting from England calculated in a matter of a few seconds that the speed of the tips was currently 180 mph. Yes, 300' diameter with a rotation just less than four seconds. That's 180mph +/- tip speed. Then I noticed a low noise that sounded like an aircraft on a quiet night 30,000 + feet up, but the pitch and volume never changed. It was the sound of the blade tips passing through the air.

The digital image has been rendered as if it were taken with infrared film to dramatically darken the deep blue sky and highlight the white wind turbine.

1 comment:

Anonymous said...

I'm sure you meant to write "quiet" night! Also, the tip speed at one revolution every four seconds would be: 3.14159 x 300 feet = 942.48 feet/revolution x 15 revolutions/ minute = 14,137.16 feet/minute x 60 minutes/hour = 848,229.3 feet/hour x 1 mile/5,280 feet = 160.65 miles/ hour. [I also was an engineer!] Although somewhat controversial, these turbines are very impressive machines.