Fly Like a Bird

Canadian researchers have achieved this ages old human dream in a 43 kg machine with a 32 metre wingspan.

A contemporary poet writes of Abbas ibn Firnas, a ninth century  Muslim Berber polymath living in Cordoba: ‘He flew faster than the phoenix in his flight when he dressed his body in the feathers of a vulture.’ A later historian, more prosaic than the poet, is slightly more informative: ‘Among other very curious experiments which he made, one is his trying to fly. He covered himself with feathers for the purpose, attached a couple of wings to his body, and, getting on an eminence, flung himself down into the air, when according to the testimony of several trustworthy writers who witnessed the performance, he flew a considerable distance, as if he had been a bird, but, in alighting again on the place whence he had started, his back was very much hurt, for not knowing that birds when they alight come down upon their tails, he forgot to provide himself with one.’ 

Firnas’ attempt counts as the first heavier-than-air flight recorded in human history. But even Firnas did not achieve what birds manage every day—taking off and flying by the flapping of wings. The dream has had to wait till our times, though it has long been perhaps the most natural of desires. 

Dozens of stories from various cultures attest to men who attempted to fabricate wings from wax and feather, only to plummet to a certain death. Of these, the Greek myth of Daedalus and Icarus is the best known. Daedalus, imprisoned in a tower for his skill at creating labyrinths, fabricates wings out of feathers, thread and wax for himself and his son Icarus. They escape, but Icarus does not heed his father’s warning and soars higher. The sun’s heat melts the wax and he plummets to his death, a warning forever for humans attempting to soar like birds.

A scientific understanding of the difficulty of human flight, as opposed to mythic caution, had to await the work of another genius. If Firnas was a poet and an inventor, designer of a water clock, discoverer of a way to make colourless glass and an elementary reading lens, his successor in the study of flight was one of the few who could outspan his range of interests: Leonardo da Vinci.

From his infancy, Da Vinci seems to have been fascinated by flight. But he also had analytic powers that were unique in their ability to encompass the world in all its diversity. For him, the answer to the problem of flight lay with birds: ‘A bird is an instrument operating through mechanical laws, which instrument it is in the capacity of man to be able to make with all its motions.’

His study of birds led to insights that were the beginnings of the scientific study of flight: ‘An object offers as much resistance to the air as the air does to the object. You may see that the beating of its wings against the air supports the heavy eagle in the highest and rarest atmosphere, close to the sphere of elemental fire. Again, you may see the air in motion over the sea, fill the swelling sails and drive heavily laden ships. From these instances, and the reasons given, a man with wings large enough and duly connected might learn to overcome the resistance of air, and by conquering it, succeed in subjugating it and rising above it.’

Among his sketches are a few for a flapping wing craft, an ornithopter, but he seems to have soon realised that it would be easier for man to fly by imitating other models. ‘Remember that your flying machine must imitate no other than the bat, because the web is what by its union gives … strength to the wing. If you imitate the wings of feathered birds, you will find [you need] a much stronger structure, because they are pervious.’

It remains a tantalising historical question whether Da Vinci himself built and flew any of his models; there is no evidence to suggest this, but the practicality of his advice and variety of his designs seem to at least hint at such a possibility. Many of his other sketches dealing with flight involve gliders with fixed wings. In doing so, Da Vinci set men on the path to flight, but the dream of flying much as birds do remained a challenge.

The most important of Da Vinci’s successors was Otto Lilienthal, a nineteenth century German flight enthusiast who also made extensive studies of birds in flight. A series of gliders that he himself made and flew paved the way for the Wright brothers. In 1896, Lilienthal’s glider plunged to the ground from a height of 50 ft. A broken spine (a fate not so different from Firnas’ or Icarus’) led to his death, but not before asserting, “Small sacrifices must be made!”

His work led to modern aviation, but human-powered flight had to wait for a considerable period. The power that human muscles produced seemed inadequate to get men off the ground. It also became clear that flapping wings were far less efficient than propeller-driven, fixed-wing crafts. The first human-powered, heavier-than-air flight was only achieved in 1976 in a pedal-powered propeller craft, the Gossamer Condor, which eventually flew across the English Channel. 

Finally, in August this year, Todd Reichert, an engineering PhD student at the University of Toronto, piloted the first continuous flight of an ornithopter  for about 20 seconds, covering 145 metres. The craft, The Snowbird, designed by Reichert along with his fellow graduate students, weighs just 43 kg with a 

wingspan of 32 metres. It works by pumping a set of foot pedals attached to pulleys and lines that control the wings in a flapping motion.

Describing  the ornithopter in detail, Reichert has written, ‘The construction methods and materials are similar in nature to previous human-powered aircraft, using custom carbon fibre tubes for primary structural elements, and using foam, balsa and bass wood for ribs and other parts of the secondary structure. Where the design differs most is in the leg-press-based drive mechanism which pulls the wings downward with each press of the pilot’s legs.’

Even so, Reichert had to undergo extensive training and weight loss to sustain the flight, which demands pedalling power close to that generated by top-class athletes, which is way beyond the capacity of most ‘normal healthy men’. 

Certainly, it doesn’t seem we can swap our bicycle for a flying machine anytime soon, even if we actually find parking for a 100 ft machine.

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