A conversation with Azhar Abidi

2008-10-17T14:04:00.000-07:00

Questions and answers on Passarola Rising

How did the Passarola fly?

2008-08-22T18:31:00.000-07:00

Passarola was a flying machine, designed like a seagoing ship with two masts and three sails. It was fifty-nine feet long from stem to stern and fifteen feet wide. The forecastle was twelve feet long and nine feet wide. Two leeboards extended on either side of the hull. A ladder from the deck led into a small room used as the armory and wardrobe. A narrow passage amidships opened into a tiny galley at the rear of the ship. Also inside the hull, there were two small cabins in the forecastle, measuring approximately eight feet by six feet. At the bottom was a hold for stores and provisions.

The only difference between an ordinary ship and this craft was that the deck was suspended underneath four large copper spheres. These were vacuum spheres that weighed less than similar spheres filled with air. They rose in air because the vacuum inside them had no density compared to the air outside. Each sphere was seven feet in diameter, with a thin copper shell less than one-tenth of an inch thick. Four such spheres displaced enough air to take account of the ship's weight and a small payload. They resisted atmospheric pressure in the same way that an air bubble resists the pressure of water around it.

The craft, designed and built by Bartolomeu Lourenco, was based on principles developed by Francesco Lana-Terzi, a Jesuit professor of physics and mathematics, in his work Prodrome dell'Arte Maestra (1670).