These are photos of rotor-kites in use during WWII. A rotor-kite is a unpowered “helicopter”, and the blades turn horizontal momentum into lift. (1st: observation rotor-kite which was towed behind U-boats. 2nd:
ArtStation - German rotor kite Focke-Achgelis FA 330 Bachstelze
PDF] Trial Production of Kite Wing attached Tricopter with Tilt Front Rotors | Semantic Scholar
BOXES AND 3D KITES
BEST BREEZES: Kites and Kite History - Journal / BLOG - Rotor Kites Move From Toy Novelty to High Tech Power Generation