Flight studies with a pyramidal linen parachute
Man against the air, weighing a wing on a balance, human-powered flying machines, and a caulked-linen canopy
The sheet develops Leonardo's argument for human flight from the reaction of air: as much force is made by the thing against the air as by the air against the thing, shown by the eagle sustained on thin air and by wind rebounding from sails to drive a heavy ship. Figures test the idea mechanically — a man on a steelyard bracing shoulder and feet weighs 400 or more than 600 pounds, and a wing's lifting force is measured by balancing a man against an equal weight and cutting the rope that holds the wing. Human-powered flying machines are worked out for one or two operators taking turns, alongside a device with a crank. At upper right is a canopy sketch with its note: a man under a caulked-linen pavilion 12 braccia square and 12 high may throw himself from any great height without harm.
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Force against the air, from eagle and sail
As much force is made by a thing against the air as by the air against the thing. The beating wings sustain the heavy eagle in the thin upper air, and wind rebounding into swollen sails drives a laden ship, so a man with great contrived wings, forcing against the resisting air, might subdue it and raise himself above it.
The caulked-linen parachute
If a man has a pavilion of caulked linen 12 braccia wide on each face and 12 high, he will be able to throw himself from any great height without harm to himself. The note accompanies a small canopy sketched at the upper right of the sheet.
Weighing a man's downward thrust on a steelyard
If a man weighing 200 pounds mounts the steelyard, sets his shoulder against a beam and presses his feet on the balance, he registers 400 pounds or more; arranged as shown below, more than 600. The figure gauges how much thrust a flyer can bring to bear.
A flying machine worked by two men in turn
The machine can carry one or two at a time, so that when one rests the other keeps working: having pressed one head of the lever he takes a great step and mounts the other, achieving the same effect. A cranked version of the device is noted simply as sufficient.
Measuring the weight a wing would sustain
To find the lift of a wing, balance a man against an equal weight so the scales hang level, then attach him to the wing's lever and cut the supporting rope so it falls, forcing a two-beat fall into one. As much extra weight as restores equilibrium is what the wing would sustain in flight — and more, the harder it presses the air.