21 January, 2011 .

55 humpback wind turbine, external surfaces .

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This model is adapted from the 56aises humpback wind turbine, (posted 13 January 2011),

and the 55 wind turbine, (posted 8 and 13 May, 2010) .

The design is intended to sync with the wind when its wingtips are traveling at about 4.94 times the wind's speed .

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A change from the 56aises design is its smooth and shorter wings .

A change from the 55 design is its humpback sectional curvature .

This progressively adds material to the trailing edge, (moving away from the hub), making it stronger .

Near the hub, the change in geometry creates a characteristic 'humpback' profile, which should be more aerodynamic .

The amount of material so added can be varied, and here it is slightly heaver than it had been in the 67aises model,

(posted 26 August 2010, upon which the 56aises was based) .

I expect that using a heavier trailing edge through the fast-turning portions of the wings will create (comparatively) more operational noise,

as well as yielding a lower efficiency overall ; but the added durability is a positive consideration .

Likewise, this model does not offer the efficiency and low noise attributes hoped of the (serrated) #aises designs, but would be far simpler to produce .

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Another notable difference from the 55 model is the reshaped base of the wings, taking up less volume and offering a cylindrical cuff .

Giving up some of the low-speed lift area near the hub should make it easier to apply and hold a brake on the turbine during extreme conditions ;

and the cuff would provide a standardized grip-point for assembly and maintenance ~ especially useful in larger models .

However, i believe that the greatest hope for wind power is to complement the huge, high-output wind farm models with many smaller ones ~

more local to the consumer ~ in an integrated power capture, storage and distribution network .

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It is my hope that this will prove to be a reliable, reasonably quiet and efficient turbine ; particularly at the consumer-owned, roof-top scale .

As a five winged design in a field dominated by three winged turbines, it would have higher up-front costs ;

however, i feel there are at least two advantages to this approach worth considering .

First, i believe this turbine can yield more energy at its sync-speed than a three winged model ~ which could also mean more energy for the amount of noise produced,

as i believe the noise has greater dependence on the velocity of these surfaces than their area ~ or, (within limits), their number .

Second, i find slender five point symmetry to be far more natural looking than slender three point symmetry .

Thus the effect on the viewshed, (and ultimately the peace of mind of the viewers), from broad distribution of five winged turbines may be preferable .

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Most of the figures in the column at left show the full exterior surfaces of the turbine,

(the two at its bottom show end-on views from inside the base, and from the tip) .

The figures below show closer views of a single wing .

The green arc in the first of these, (and the gray arcs in the last), mark(s) where i expect ripple effects from other wings to be centered .

The outermost of these would be created when variable winds cause the tips to over-run sync-speed, (its location is approximate) .

The column at right provides a closer look at the hub area .

The banding on the mounting flanges is a display artifact .