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Dr. Alexander Graham Bell.

When you ask most people what Alexander Graham Bell was most famous for they will probably be able to tell you that he was the inventor of the telephone, which would later become known and used as an everyday appliance, the home phone. Some people may even know that it was invented in 1876 and that he later invented the gramophone.

Very few people realise that Bell had a great passion for both aeronautics and kites. He used kites to further his knowledge of man assisted flight. Bell designed, made and tested many of his own man-carrying kites himself.

To begin with Bell concentrated on the lifting aspects of the kite and experimented with rotors and winged flying wheels. Some of these were able to reach a height of more than 150 feet.

Bell used a variety of geometrical shapes in his kite designs. Geometry is a branch of mathematics concerned with the relationship between points, lines, surfaces and solids.

The kite on the right is a huge twelve-sided giant radial-winged kite. A man is holding the tail or landing-line and is controlling the kite on the ground.

The Bell Family. Courtesy of the National Geographic society.

The image below shows Bell holding one of his kites. The kite is made up of two hexagons (a six sided shape).

Each hexagon has six radial divisions or wings. The two hexagons are held together with a centre pole having a moveable weight in the centre of it. The adjustable weight could slide along the pole in order to find the centre of gravity. At this point it is perfectly balanced.

The photograph is courtesy of the National Geographic Society.

The photograph below shows Bell with one of his tetrahedral structures. A tetrahedron is a four-sided solid, triangular pyramid. The two large tetrahedral shapes at the ends are attached together with a framework of smaller, hollow tetrahedrons.

This design was later made into a winged boat in 1902.

Bell found the tetrahedron to have a very good strength to weight ratio. This simply means that an object is structurally very strong but at the same time is very lightweight.

Metal girders and beams in most modern buildings are made of hollow steel beams. Centuries ago beams in houses were made of solid wooden beams. They were much heavier than the metal beams and were not as strong.

Bell continued to experiment with the tetrahedron. He built a kite called the Frost King, which was made up of 1,300 tetrahedron cells. The kite accidentally lifted one of its handlers some 30 feet above the ground.

The kite, including all of its tackle weighed just 125 lbs; the weight of the handler was 165 lbs. 10 miles per hour wind was recorded. The pull of the kites was measured using a standard spring scale. These can be found in most school science laboratories.

From this Bell concluded that a much larger kite, carrying an engine, providing a 10 m.p.h. thrust would easily carry a man.

The first controlled man-flight, in one of Bell's kites took place in 1907. The kite was named the Cygnet, a much larger version of the Frost King. This kite contained 3,393 cells and carried floats to enable it to land on water.

It was towed behind a steamship to a height of 168 feet. The pilot Lieutenant Thomas.E. Selfridge survived the seven-minute flight unfortunately because the winding crew onboard the ship were too slow to unwind the towrope the Cygnet hit the water and broke up on contact.

Selfridge died seven months later while flying as a passenger of Orville Wright. He became the first person to die in the history of powered flight.

Bell later created the Cygnet 11. This version of the Cygnet 1 carried an engine and a man unfortunately the engine did not have enough thrust to raise the kite and man.


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