Beating-Wing Studies and the Four-Winged Dragonfly
Flapping-wing mechanisms, a screw and a winch, with notes on dragonfly flight
Across the sheet Leonardo studies flapping flight: linkages for a beating wing (marked B and A) in which one wing must fall as the other rises, so that a part is always pressing the air, and a schema of a dragonfly with its four wings open, where the front and rear pairs alternate and each pair must be able to carry the whole weight alone. Supporting mechanisms include a double-thread screw worked out in six turns, a reduction gear and a stout winch (burbera). A marginal note reminds him to go to the ditches to watch the black dragonflies fly with four wings.
On this page
Beating wing: part B rises as part A falls
For the wing linkage marked B and A, when part B rises the part A must lower, because there must always be a part that beats the air. Leonardo notes this arrangement is necessary here.
Dragonfly flying with four wings
The dragonfly flies with four wings: as the front pair rises the rear pair falls, and the reverse. Each pair on its own must be sufficient to sustain the whole weight.
Double-thread screw in six turns
A screw with a double thread is set out in six turns. It belongs to the driving gear that powers the flapping mechanism.
Winch (burbera) geared one-third
A stout winch is one-third thick, so that for every turn it advances from one braccio to one-third. Its stops are marked fixed and fixed.
Go to the ditches to watch dragonflies
To study flight with four wings, Leonardo tells himself to go to the ditches, where he will see the black dragonflies. It is a reminder to observe living four-winged flight directly.