# Rant: Why is AWE maybe better than HAWT

So I see two possible benefits for utility scale AWE

• Less material use

I think only the second one makes much sense, the first one I consider a perk.

The power output of a wind power plant is very dependent on \frac{C_L^3}{C_D^2} (lift coefficient times glide ratio squared). For a HAWT, the same can be expressed by tip speed ratio TSR. But for windmills there is a max TSR possible because you will eventually be hitting the Betz limit (or in other words the wake of the blade in front).

This I believe is the biggest «break» for AWE, considering all added complications AWE entails. There is no max limit to glide ratio for AWE in terms of swept area diameter. because you can so easily just expand the diameter to accomodate a higher TSR/glide number.

This, if you are with me so far, means that utility scale AWE should focus on higher glide numbers. This is already quite difficult as HAWT have laid the bare really high. But maybe

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Yes. A high number can be achieved in two ways, possibly by combining them:

• The “usual” way, being a high lift-to-drag ratio

• A very high lift coefficient as for Flettner (until 8 at a spin ratio of 3 or 4) or Sharp (until 3) rotors, or as for High lift coefficient and biplane kite, the last being able to be combined with the previous (high lift-to-drag ratio).

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