Lenz2 wind turbine

Step 3 Revision: A change inthe shape of the wing

The original shape of the wing presented in this instructable is not quite according to the plan posted for the Lenz2. After consulting with Ed Lenz, I became aware of the mistake that I have made in interpreting his plans. The new design is illustrated in this step.

Notice that the angle labeled "Angle A" is 90 degrees. Side A is at a right angle to the diameter line of the rounded end of the wing. In the original design that I presented in this instructable, the two lines forming the pointed end of the were of equal length and their angles to diameter line were identical. That cone was symetrical whereas in the change being shown here, the cone is not symetrical. Making Angle A to be 90 degrees will give the wing more lift

I have resized the design so that I can drive a minigen generator that had been sold at windstuffnow.com (but is no longer available). The basic steps in fabricating the lenz2 are still valid.

Basic Calculation:
I now understand better how to determine the size and proportions of the wing. You first determine what the diameter of lenz2 will be. The easiest way to do this is to decide what the distance will be from the center axis of the lenz2 to the outside edge of a wing. This will be the radius of the lenz2. You double it to get the diameter.

In my new design, I made the assumption that the diameter of lenz2 will be 16 inches (that is, the distance from the center axis to the outside edge of a wing will be 8 inches).

To determine the diameter of the wing, multiply the diameter of the lenz2 times .1875. In my example, 16 inches * .1875 = 3.0 inches.

To determine the length of the wing, multiply the diameter of the lenz2 times .4. In this case, 16 inches * .4 = 6.4 inches. The length of Side A is 6.4 minus 1.5 or 4.9 inches.

I will be creating a new instructable that will include this design in a lenz2 that drives a minigen generator

Comments

[Robert_13]

Oops! That last part of the math expressions should have read:

1/2.618034 = .3819661, 1 - 0.3819661 = 0.618034

[Robert_13]

I wonder whether this design was arrived at empirically first and then tweaked to conform to the interesting mathematics of it, or the reverse. I notice that the proportion of outside degrees of arc corresponding to vanes and to the open spaces between them is right on the Golden Mean (1.618034 or its reciprocal, 0.618034). The angle of the vanes with respect to a tangent to the circumference has a tangent very close to 0.618034 (3/4.9 = 0.612, or a 0.9% difference).

I would think the rationale behind this is that the Golden Mean has very interesting self-referential and scale invariant properties. Since air is essentially scale invariant macroscopically at low wind speeds, I would expect the self-referential nature of the Golden Mean to produce a high probability of self-reinforcing aerodynamic behavior. (1/1.618034 = 0.618034, 1.618034^2 = 2.618034, 1/2.618034 = 0.381966 = 1 - 1.618034, etc.)

[conntaxman]

Isn't the width of the wing to wide for the length?when making a large wind turbine isn't the Diameter to large? say the diameter of the wind turbine is 8 foot. that would mean the dia. of the wing is 18 inches.and the length is only 38.4 inches.Isnt the "bucket" diameter of 18 inches too large to cut through the wind? Im wondering which is more important,the length or the bucket. tks Johnny I had made one that is Y i ask.very low rpm,.Mine was 3 blade,hight of blades were 54" length 46" Bucket diam was 19" Next I want to make a 5 blade one and trying to figure out a smaller diameter bucket so it would cut through the on comming wind. Yes it did have alot of tork