10' blade power at 3 different wind speeds

[picmacmillan]

below i will use the formula given by hugh to demostrate how much more power can be made by increasing the wind speed....i will use 10' diameter blades, and 10,15, and 20 mph wind speeds.

  .the formula: blade power(in watts=0.15xblade diameter(squared)xwindspeed(cubed)

                                                 (in meters)  (in meters per second)

10 mph example    power in watts =0.15x3.05(squared)x4.5(cubed)

                                 =127.1 watts

15 mph example    power in watts = 0.15x3.05(squared)x6.71(cubed)

                                 =421.4 watts

20 mph example    power in watts = 0.15x3.05(squared)x8.9(cubed)

                                 =983 watts

      CONCLUSION: 10' blade x 10 mph wind =127.1 watts

                  10' blade x 15 mph wind =421.4 watts

                  10' blade x 20 mph wind =983   watts

There is a substantial increase of power created with a 10 mph increase of wind speed.........pickster

[johnlm]

Your right Pic, the power available at higher wind speeds is pretty impressive.  For my tastes, I enjoy watching my smaller 2 to 4 ft diameter units putting out like a banshee in 20 and up mph winds, but when watching my bigger unit in this kind of wind, I usually kinda wish the wind would drop down to 15 mph or so. Thats why I usually set the furling pretty low, to save stress on the hardware. Maybe I just havent made it strong enough.  This reminds me of the post a few days back where the company rated the output of their Hornet model in a 65 mph wind, and showed curves up to 100 mph or something like that. (One had to squint at the graph to see reality in the 5 to 20 mph range)  Sure hope the guy (on a recent post) asking for guidance on the camp trailer need doesn't (mistakenly) get a Hornet thinking he can light it (the camp trailer) up like a city.

John

[finnsawyer]

O. K. Pic, chew on this.  When air flows around a sphere it's speed increases by 50% near the sphere halfway around.  It then drops with distance from the sphere.  Similarly, when air flows around a cylinder it's speed doubles.

[ghurd]

I'm just getting my blades figured out and now you tell me I should add 8 cylinders around them!



G-

[finnsawyer]

No. But maybe you should put your blades around a sphere or a cylinder.  I just thought that since you were so impressed by the cubic wind power function, you might be interested in some other remarkable wind behavior.

[pyrocasto]

So then One BIG sphere in front of the genny, would make it do better?