Mechanical wing with horn and quill springs
Iron-wire, horn and quill springs for a flapping wing; a November reminder
A large drawing of a mechanical wing (n-r-m-o-f) built of membrane 'or of flying fish' dominates the sheet, with a schema showing that a is the first motion. Leonardo proposes replacing the spring with bundles of thin tempered iron wires of equal number, thickness and length so that the springs have equal power and resistance. Several spring studies follow, including a closed spring held by a thread and a feather-spring with a strong element b and a weak, bending element a, to be modelled from writing quills. A memorandum in the upper margin notes 'six Thursdays throughout November.'
On this page
A mechanical wing and its first motion
A large wing figure n-r-m-o-f is to be made of membrane or of flying fish (swallow-fish). A wing schema marks a as the first motion. In place of a spring, Leonardo would take thin, tempered iron wires of the same thickness and length between the bindings, so that with equal numbers of wires the springs have equal power and resistance.
Feather, horn and closed springs
A detail spring of feather has a strong element b and a weak, readily bending element a that can easily meet b, with a little leather between them to hold firm; the springs are to be of ox horn, and for the working model made of writing quills. A closed spring n-o is held by a thread so it does not straighten out.
Wing schema, first motion
A separate wing diagram is labelled a and annotated that a is to be the first motion, with a note to take apart a flying creature.
A November reminder
A jotting in the upper margin notes 'six Thursdays throughout November', an isolated calendar or scheduling memorandum unrelated to the flight studies.