For millennia, men and women have studied birds, bats, and beetles, observing and experimenting, attempting to determine what humans must do to fly by flapping.
But people can’t fly by flapping: not with wings covering their arms; not with pedaled, chain-driven wings; and, so far, not with internal-combustion engines, either. Nonetheless, the concept of manned ornithopters continues to hover on the periphery of aeronautical engineering. This project shows you how to build a small, rubber band-powered ornithopter we call Orly.
There are many types of ornithopter designs. Orly is a simple monoplane, meaning there is a single wing mounted above the motor-stick, and its motion is similar to a bird in flight.
How do ornithopters fly? According to Nathan Chronister of the online Ornithopter Zone, “The ornithopter wing is attached to the body at a slight angle, which is called the angle of attack. The downward stroke of the wing deflects air down- ward and backward, generating lift and thrust.
“Also, the wing surface is flexible. This causes the wing to flex to the correct angle of attack we need in order to produce the forces that we want to achieve flight.”
The mechanics of flapping flight are far more complicated than that of fixed-wing flight. For an aircraft with fixed wings, only forward motion is necessary to induce aerodynamic lift. But for flapping flight, the wing not only has to have a forward motion, but also must travel up and down. This additional dimension means the wing constantly changes shape during flight.
Without doubt, even the earliest humans watched birds fly past and felt, well, rather envious. Thus when Thag, a Pleistocene caveman, looked up and saw flocks of ducks and geese soaring above, he might have gathered together a few palm fronds, lashed them around his arms with a vine, and leapt off a tree. Poor Thag never got airborne, or at least he didn’t live to record the episode in petroglyphs on his cave wall.
Later, from ancient Greece, comes the legend of Daedalus and Icarus. Daedalus was a skilled engineer who angered King Minos. Minos ordered him imprisoned in a tower.
According to Bulfinch’s Mythology, “Daedalus contrived to make his escape from his prison, but could not leave the island by sea, as the king kept strict watch on all the vessels.
“So he set to work to fabricate wings for himself and his young son Icarus. He wrought feathers together, beginning with the smallest and adding larger, so as to form an increasing surface. The larger ones he secured with thread and the smaller with wax, and gave the whole a gentle curvature like the wings of a bird.”
Unfortunately for Daedalus, the attempt at flight didn’t entirely work. His son, Icarus, flew too near the sun, melting the wax that held the wings together. Icarus fell out of the sky and drowned in the ocean.
To a large extent, that’s been the typical outcome of human flapping flight experiments, right up to modern times.
The New York Times has run many stories over the years:
Around 1490, Leonardo da Vinci was carefully studying the mechanics of avian flight. From his bird-watching came perhaps the first blueprint for a human-carrying ornithopter. More of a theoretician than a true maker, Leonardo never got his flying machine off the paper in his notebooks. Had it been built, it likely would not have flown. Still, experts say his design is clever, and embodies modern aerodynamic principles developed hundreds of years later.
Interest in flapping flight took off again in the 1870s. Building model ornithopters became fashionable in Europe, and a number of enthusiasts — among them Alphonse Penaud, Hureau de Villeneuve, and Gustave Trouvé — built internally powered birds that soared over the fields of France and Flanders. Soon, ornithopters powered by rubber bands, gasoline, electricity, and even gunpowder were flapping away, but as scale models, not people-carrying aircraft.
Since then, many people have tried to build a manned ornithopter, but none have yet succeeded. There are unconfirmed reports that the Germans made one during World War II and that the Soviets flew one during the Cold War, but solid evidence is lacking. Today the University of Toronto is making a game attempt.
Why bother with ornithopters at all? Because flappers can do things other aircraft cannot. They probably have the best maneuverability of any aircraft. Unlike fixed-wing drones, ornithopters, at least in theory, can stop and hover like a humming- bird, which makes them extremely versatile, and they need less space to maneuver than a helicopter. Couple all that with their ability to fly at very slow speeds, and ornithopters may be the perfect surveillance vehicles. The military applications for unmanned ornithopters are numerous.
Ornithopters have practical applications in civilian life, as well. For instance, the Colorado Division of Wildlife uses an ornithopter to research a hard-to-capture endangered species called the Gunnison sage grouse. This skittish bird flies away at the first sign of danger but will stay on the ground if it sees a hawk flying above. So state biologists use a motorized, radio-controlled ornithopter painted like a hawk to keep the flighty grouse on the ground long enough for them to capture it.