Skywriting
Skywriting is the process of using a small aircraft, able to expel special smoke during flight, to fly in certain patterns to create writing readable by someone on the ground. The message can either be an advertisement aimed at everyone in the vicinity, a general public display of celebration or goodwill, or a personal message such as a marriage proposal writ large.
The typical smoke generator consists of a pressurized container holding a low viscosity oil such as Chevron/Texaco "Canopus 13" (formerly "Corvus Oil"). The oil is injected into the hot exhaust manifold causing it to vaporize into a huge amount of dense white smoke.
Skywriting is never a permanent process. Wind and dispersal of the smoke cause the writing to blur, usually within a few minutes. However special "skytyping" techniques have been developed to write in the sky in a dot-matrix fashion, and are legible for longer despite the inevitable blurring effect caused by wind.
Despite its transient nature, skywriting has an obvious visual impact and can be considered a form of visual pollution.
One of the earliest mass media exposures of skywriting appeared in the 1939 movie version of The Wizard of Oz, when the wicked witch of the West writes in the skies over Oz, "Surrender Dorothy".
The first use of sky writing for advertising purposes was in 1922.
See also
External links
 | This aviation-related article is a stub. You can help Wikipedia by expanding it. |