High lift coefficient and biplane kite

I realize that power is Cl^3 and Cd^2, BUT:

Cl and Cd are connected. Increasing Cd will most likely also increase Cd. Cd will probably increase relatively more in the process. Look at that last foil in the series of four: the lift is pointing very much backwards.

Next, we realize that increasing Cl above 1.5 is not really that easy. You need multi profile or other tricks, and with these tricks your wing may not fly as well as the simpler normal wing profiles (eg stalling and nonlinearity issues, as a software guy I wouldn’t know the details?).

If we assume that Cl/Cd is fixed, the power is only proportional to the Cl. So if you can increase the Cl from 1.5 to 4.5, you will get 3x the power. In reality I expect for these profiles, Cd will scale relatively faster than Cl, and in effect we are perhaps only getting 2x the power, and a wing that is difficult to produce and control in addition.

Now there is another option that would also give us the same effect. Increase the wing area by 2x. I think if you are seriously considering going for a wing like this, you might consider that option as well. Perhaps even the wing with twice the area will weigh less, after all structural weight has been added

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