Hot Air Balloon Book: Build and Launch Kongming Lanterns, Solar Tetroons, and More

Hot Air Balloon Book: Build and Launch Kongming Lanterns, Solar Tetroons, and More — page 7
Lana's airboat In 1663 Lana designed a lighter than air ship the details of which he later published in 1670 in his book Prodomo This design used four large floating copper spheres from which a boat is suspended The boat had a sail and hull as Lana intended it to be propelled by the wind and steered much as a boat on the sea Lana never tried to build his airboat and of course there would have been practical problems if he had To make the airboat fly I estimate that the copper skin of the big spheres would have to be less than 0 004 inches 0 1 mm thick This is about the thickness of a human hair and only about four times the thickness of household aluminum foil At this thickness the sphere would collapse under its own