From Leonardo da Vinci, F Manuscript, f. 16v.
Heavy weight lifting.
The cylinder that makes a deflagration chamber is placed up high and thanks to a pipe the gases produced by powder deflagration pass in the expandable chamber underneath the platform with the load.
Dimensions: In Leonardo’s description of this machine he says that the “vase” should be empty by one fathom (Milanese fathom = 59.49 cm) and ten long. Nevertheless, this data is not easy to interpret because, if it refers to the cylinder in which the explosion takes places, meaning the diameter as empty and the length as the height, we would have a “cannon” about 6 meters high, which would make it extremely difficult to maneuver even as an experiment. It is more likely that the 6 meter length is the total height of the machine as the ratio between the cylinder diameter and machine height taken from the drawing (approximately one to ten) seems to conﬁrm. Even if only hypothetically, we can conclude that the cylinder height is about 1.8 meters, whereas the gas expansion chamber (the bellow at the bottom) seems to be able to dilate to reach a height of two meters.
Reconstruction: it is deﬁnitely an experimental device that was never realized. From the drawing it is unclear if the disc inside the cylinder on which the ignition starts is really a piston, and the cryptic description of Leonardo has open to various interpretations.