These are the cosines according to the angles. I did not notice any difference with the values given in the pdf. But as you know (see the quote from your comment below) the cosine losses are cubed. I am providing the rounded cosine values in decimal form for only angles of 60 degrees and 80 degrees to more easily give the values in cubed cosine.
Cosines for elevation angles of 60 and 80 degrees:
60 degrees: 0.5
80 degrees: 0.173.
Power after cosine cubed losses:
60 degrees: 0.125 (not much power)
80 degrees: 0.00517 (so almost no power).
AWE systems. HAWT = horizontal axis wind turbine. For the rest, see above, but to summarize, considering the power, losses are cubed. So what you indicate is true, excepted “In addition”.
Indeed the cubed cosine loss is applicable for all AWE systems, without any exception, even for Kiwee where the horizontal axis of the propeller corresponds to a cosine of 1 (for an elevation angle of 0 degrees), leading to an absence of cosine losses, whatever the angle of elevation of the lifter kite.
So there is a difference between AWES that carry a wind turbine and AWES that constitute the wind turbine.
A lot of AWES constituting the wind turbine work at a low elevation angle, 30 degrees for example. As the cosine is 0.8660, the power after cosine cubed losses is about 0.65: it’s a lot losses (35%) but still acceptable.
Essentially, I agree that Kiwee is a good option, and surely the best, and not just because of the absence of cosine loss (which is actually offset by the requirement for a relatively large lifter kite in relation to the greatness of the elevation angle of the said kite, which limits the advantage of no loss): the rope drive transmission allows for high lengths of rope while maintaining efficiency, unlike TRPT and similar like Tiira.
But tilted rotary devices, including Tiira, The Pyramid, Daisy, SuperTurbine™, could perhaps compensate with other advantages, taking into account that these devices are different each other.