Back Ground
The Renaissance was a time of great invention, idea and thought. This was the period of time that followed the Dark Ages and of hardcore Religious oppression, the horrors of the Black Plague, and a large population of impoverished, uneducated peasants. The Renaissance was started it the golden age of Italy, in which many inventors erupted into creation. During this time inventions, paintings and engineering was the main objective society, and among this society one man would rise to become the most famous innovator of the Renaissance. His name was Leonardo Da Vinci.
Flight Study
In his time Da Vinci posed many questions about how to make a device that allowed humans to fly. He had come up with several different ideas and blueprints to crafts of flight, including a "helicopter", glider, and even a parachute to be a
ble to fall from large heights. During his study of flighthe researched the wing structure of a bat. A bats wing structure is such that it is similar to the bone structure of a human arm.It is also more nimble than that of another type of bird's wing type, which would be heavier. But Da Vinci didn't necessarily need to completely mimic the structure of a bat wing. During his study he learned that the inner part of a wing moved slower than the outer part, so he would need to make wings that could sustain flight, not just to move in a forward motion. He used this idea to hep him make a contraption that would be adapted to the use of a human. This study would lead him to create the Ornithopter.
The Ornithopter
The definition of an Ornithopter, one of the many flight crafts that Da Vinci had imagined, is a heavier than air craft designed 
to be propelled through the air by flapping wings. It was designed around the year 1485, but it is unclear to whether Da Vinci actually build or tested this machine. Created by the idea of the study of bat wings, Da Vinci's device was designed so that a person could strap themselves in and use their lower torso and legs as the muscle for maneuvering during flight. He used this concept to create a simple drawing, in which the wings were directly attached to the person
His drawings of the Ornithopter were written in sanguine and a pen. There were three of them in a portfolio, known as Codex Atlanticus, Folio 846 v. Each sketch portrayed a different angle of the craft.
Modern Day Ornithopters
Da Vinci's Ornithopter was in fact an innovator of the way flight would be studied and continues to be an inspiration for flight machines created around the world. Many inventors and fans of Da Vinci's works decided to recreated his amazing machines into modern works. The top right picture is just one of the many examples of how people have interpreted his ideas. Todd Reichert, a student studying engineering at the University of Toronto, made this version of Ornithopter, which would be known as "Snow Bird". This machine could be called successful, because it was able to stay in the air for 19.3 seconds and covering a distance of 475.72 ft. It was made from the materials balsa wood, foam and carbon fiber, and it's weight totaled 92.59 pounds. In flight this machine moved at a rate of 15.91 mph. This is a real life example that Da Vinci's simple sketches in fact had the right idea in creating modern flight. The picture on the middle left is another version of the Ornithopter, known as "The Flapper". This was yet another creation by the University of Toronto's Institute for Aerospace Studies. This modern version of the flight machine was envisioned by James DeLaurier from the Institute of Toronto. Another picture of this same device is displayed at the bottom left. These modern examples prove that Da Vinci's studying and thought were in fact a possibility to be put into reality.
Comparing/Contrasting:
Of course the modern renditions of the Ornithopter aren't completely similar. Today we have stronger materials, more advanced scientific methods and tools that are at our desposal. While the modern "Snow Bird" or "The Flapper" mimic Da Vinci's design, they are all too different in that Da Vinci's design was on a much smaller scale, built with wood materials and weighed much less than these modern interpretations. So overall no modern replica has truly captured the vision of Da Vinci.
Bibliography
http://en.wikipedia.org/wiki/Renaissance
http://en.wikipedia.org/wiki/Leonardo_da_Vinci
http://cleantechnica.com/2010/09/27/leonardo-da-vincis-human-powered-flying-machine-flies-video/
