To not tamper with load carrying sail, it is a better idea to ‘roll out’ a largish ‘solar cape’ to charge batteries while flying steadily for long intervals
it could even be ‘rollable’
unrolled to flutter behind (like a submarine’s mile long antenna wire does)
I’m not a fan of Super Man or his solar powered Super Cape. When I want to extend my flight times, I use a really, really long extension cord. Just like Spider Man:open_mouth:
I’ve been paragliding with a small flag, less than 3 ft long, and it added a lot of drag. More drag than what a solar panel would compensate for. Your load carrying surfaces are designed to be highly aerodynamic.