Tetrahedral kite

A tetrahedral kite is a multicelled rigid box kite composed of tetrahedrally shaped cells to create a kind of tetrahedral truss. The cells are usually arranged in such a way that the entire kite is also a regular tetrahedron. The kite can be described as a compound dihedral kite as well.

An early design of the tetrahedron kite from Alexander Graham Bell

A tetrahedral kite being flown

This kite was invented by Alexander Graham Bell. It came about from his experiments with Hargrave's box kites and his attempts to build a kite that was scalable and big enough to carry both a man and a motor. As such, it was an early experiment on the road to manned flight. He worked on the kites between 1895 and 1910.[1] Bell wrote about his discovery of this concept in the June 1903 issue of National Geographic magazine; the article was titled "Tetrahedral Principle in Kite Structure".[2]

From an initial one-cell model, Bell advanced to a 3,393-cell "Cygnet" model in 1907. This 40-foot-long (12.2 m), 200-pound (91 kilogram) kite was towed by a steamer offshore near Baddeck, Nova Scotia, on December 6, 1907, and carried a man 168 feet (51.2 metres) above the water.

Bell also experimented with a large circular "tetrahedral truss" design during the same period.[3]

The tetrahedral kite is stable and easy to fly, but is not a light-wind kite. The large number of structural spars makes it relatively heavy and it requires moderate to strong winds.