When we think of the first aircraft, many of us think of the hot air balloon. But the helicopter actually predated it by thousands of years. As early as 400 BC, people knew that rotary devices could fly.
Perhaps the earliest helicopter-like device was an ancient Chinese children's toy made out of bamboo. It consisted of a propeller attached to a stick in a T-formation. When the stick was rolled quickly between the palms and then released, it flew a short distance.
The ancient Chinese may have gotten the idea for their toy by watching nature. Many trees disperse "helicopter" seeds, which are single seeds with a stiff, membranous wing on one end. The wing has a slight pitch, causing the air to move beneath it in such a way as to make the seed spin as it falls. This causes the seeds to scatter more widely than they would if all the seeds on the tree simply fell straight down.
The Chinese bamboo-copter made its way to Europe via medieval and Renaissance trade routes, and undoubtedly inspired one of the greatest minds in history, Leonardo Da Vinci, to take the design to the next level.
In 1493, Da Vinci diagrammed an "aerial screw" with a single spiral blade attached to a platform. According to his own writing, Da Vinci never intended to design the device for practical flight; instead, he used it as a means to test a propeller's "tractive efficiency." He envisioned the blade to be constructed of linen coated in a layer of starch to make it airtight.
In theory, this early helicopter could be powered by four men standing on the platform and pumping bars in front of them. Da Vinci notes the possibility of building a paper model using a small spring as a power source.
Centuries later, two French inventors, Launoy and Bienvenu, designed a helicopter with two rotors on either end of a single shaft. This device had two contra-rotating blades that moved in opposite directions. This counteracts torque, which causes the body of the helicopter to rotate in the opposite direction as the rotor. With two contra-rotating blades, torque is canceled out. The blades are placed on the same shaft, making them coaxial.
In practice, however, helicopters needed adequate force to turn the propeller before a vessel large enough to carry a person could truly take flight. When the steam engine was developed, inventors at last saw possibility in the old designs of Da Vinci. The first to build a working helicopter with a motor was the French inventor Gustave de Ponton d'Amecourt. He designed a steam-powered flying device made from lightweight aluminum. While it never flew, the model was the first to use an engine.
It was the internal combustion engine, however, which gave the helicopter its real power. In the first decade of the 1900's, a series of inventors designed helicopters with contra-rotating propellers and internal combustion engines.
In 1907, the Gyroplane No. 1, invented by two brothers, Louis and Jacques, Breguet, lifted a person a few feet off the ground for a minute. This was considered the first manned helicopter flight, but it was not unassisted--the craft was extremely unstable, and required assistants on the ground to keep it steady.
In the 1920's, the helicopter as we know it today began to take shape. Inventors developed craft with cyclic pitch, which allows each blade to be angled individually to control the craft's movement forward and backward; a rotor hub that tilted, allowing the craft to move side to side without a separate propeller; and autorotation, which allows the propellers to be turned by the surrounding air if the engine fails, making a safe landing possible.
The helicopters of this time managed flights of up to fourteen minutes, and reached maximum heights of fifty feet. Mass production didn't occur until World War II. During this time, Nazi Germany developed the most high-tech helicopter of its time, used in limited quantities during the war.
In 1942, the U.S. Army began mass-producing a helicopter used for rescue missions. The British Royal Air Force set up a helicopter training school. The first helicopter approved for commercial use was the Bell 206, which was made available to the public in 1946.
Today, helicopters can hover, move forwards and backwards, and perform many other aerial maneuvers impossible to repeat in a plane. Their extreme maneuverability makes them ideal for military missions, dangerous rescue missions in varied and wilderness terrain, use as flying ambulances, and more. There's no question that ideas from thousands of years ago have given us one of our most useful and versatile flying machines.
