Leonardo watched birds and bats for years before drawing a frame a person could lie in and flap. Pedals and pulleys drove the wings. Human muscle was never strong enough, but his study of the wing was far ahead of its time.

1. i.Spar, ribs and membrane are inked
2. ii.Pulleys beat the bat wings
3. iii.Enough beats, and it leaves the ground

After Manuscript B, Institut de France.

A spiral of starched linen around a mast, turned by men pushing bars around a platform. Leonardo hoped it would grip the air the way a screw grips wood. It is often called an ancestor of the helicopter.

1. i.Platform and mast go down first
2. ii.The crew turns the linen spiral
3. iii.It climbs, at least on paper

After Manuscript B, folio 83v.

A sloped wooden shell to turn aside enemy shot, ringed with light cannons. Inside, the crew turned cranks that drove the wheels through a train of gears.

1. i.Shell, turret and cannons are inked
2. ii.Cranks roll it forward; the shell lifts away
3. iii.The cannons fire around the rim

After a sheet in the British Museum, London.

Some twenty-four metres across, on six splayed wheels. A winch at the back hauls the string to a trigger. The bow arms were built in thin layers so they could bend without snapping. It may have been meant to frighten an enemy as much as to hit one.

1. i.Carriage, wheels and the great bow
2. ii.The winch draws the string back
3. iii.Release

After the Codex Atlanticus, folio 149r.

A heavy box drops, a long arm whips over the top, and a sling flings the stone further still. Leonardo also sketched the curved paths that thrown stones and cannon shot follow through the air.

1. i.Frame, arm and counterweight
2. ii.The weight drops and the arm swings
3. iii.The stone traces its arc

After studies in the Codex Atlanticus.