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Non-Tech : Alternative energy -- Ignore unavailable to you. Want to Upgrade?

To: No Mo Mo who wrote (5545)	11/14/2008 2:26:46 PM
From: Ira Player	Read Replies (1) \| Respond to of 16955

"The modern turbine blades are HUGE and move slowly enough for birds to get out of the way." Not completely accurate: The Gamesa G90-2.0 MW rotates between 9 and 19 RPM, which looks really slow when you view it from a distance. However, with a swept diameter of 90 Meters, the circumference at the blade tip is 283 Meters. At 9 RPM, thats 152.7 KPH or 95.4 MPH At 19 RPM, it's 322.3 KPH or 201.5 MPH Not slow to most birds I've seen. However, they are very tall and tend to be above the height at which most raptures hunt, so the death rate is very low compared to smaller turbines. Ira

To: No Mo Mo who wrote (5545)	11/15/2008 7:55:04 PM
From: Eric	Read Replies (2) \| Respond to of 16955

Well the nice thing about the bigger turbines that are manufactured today is the slower speeds. Tip speeds are still very fast though. The critical thing as these things get bigger is to keep the "tip speed" below the speed of sound. Drag coefficients go up significantly as they near the speed of sound. So in apparent terms as these things get bigger they will appear to turn slower. regards