Up, Up, and Away?

“Around 1000 years ago, the Turkish scholar Ismail al-Jawhari strapped feathered wooden frames to his arms and torso, and leapt from the roof of a mosque”

Credit: Danielle Crowley[br]Could humans ever achieve independent flight? Ellen Nugent investigates.OVER 5000 years ago, the mythological Babylonian King Etana flew to heaven on the back of an eagle. In the 16th century, artist and inventor Leonardo da Vinci designed his flying machines and parachute prototypes; the Wright Brothers flew the first “heavier than air” aircraft for a sustained flight in 1903. Humans have always been fascinated by the concept of flight; our history rich with invention and experimentation in flight technology.One of the most famous stories of human flight, however, makes no mention of complicated machinery, or even helpful eagles: the myth of Daedalus and his ill-fated son, Icarus, who flew from Crete with nothing but wings of bird feathers, wood and wax.Humans have been trying to recreate this particular Greek legend for hundreds of years. Around 1000 years ago, the Turkish scholar Ismail al-Jawhari strapped feathered wooden frames to his arms and torso, and leapt from the roof of a mosque. Much like the Portuguese nurse Joao Torto, who in 1540 jumped from a cathedral tower with a pair of cloth wings and a beaked helmet, his subsequent “flight” (and life) ended rather abruptly.So is it possible, with the technology and knowledge available today, that we could succeed where these early experiments failed?Unfortunately, the work of Renaissance mathematician and physicist Giovanni Borelli indicates that Daedalus’ invention is still an impossibility. Borelli concluded in 1680 that human muscle was inadequate for independent flight – we would be incapable of generating sufficient energy to lift ourselves off the ground, and staying aloft for an extended length of time.It’s not just about lift force, however. Humans have evolved to walk upright, a feature reflected in our skeletal structure. Some of these features include our legs, which are longer than our arms, to support our striding gait. Our distinctive ‘s-shaped’ flexible spinal column also accommodates our upright stance and high center of gravity. In order to facilitate independent flight, we would require longer arms, to allow for a greater wing surface area, and short legs, to reduce body weight.An inflexible, shorter spine would also be required to prevent our lower half from hanging down and generating resistance, among other morphological features. We also lack supplementary respiratory organs (for example, avian air sacs) that would allow for extra air intake at high altitudes, or further oxygen metabolism to support the energy expended on flying.All of this would be very difficult to evolve and it is unlikely that humans could ever achieve independent flight. Our brains may have allowed us to transcend the limits of our bodies with the advent of aviation technology, but independent flight remains no more than a fantasy.