Leaf-spring engine for flying machine

This flying machine was designed to be driven by the mechanical power produced by a leaf spring, which was to drive the wings. This model is most interesting, in that it testifies to the fact that Leonardo was trying to fit the leaf-spring mechanisms in use for land machines to his flying devices. Not only that. The use of a leaf spring in place of human strength bears witness to Leonardo's realization that human strength alone would hardly manage to make mankind fly. The Museum model combines this idea with Leonardo's Articulated wing study.
Codex Atlanticus, sheet 1007