An aviation technique in which an oil-based liquid is added to an airplane’s exhaust system, creating words or images with the resulting bright white smoke against a clear blue sky.
British war pilot J. C. Savage was the first to write an aerial message in the skies over England, in 1922. In the fall of that year, Captain Allen J. Cameron brought skywriting to the United States when he wrote “Hello U.S.A.” in the sky over New York City. An advertising executive for the American Tobacco Company saw the message and signed Cameron to a $1,000-per-day contract to promote the cigarette company.
Since the early days of aviation, one of skywriting’s biggest advertising advantages has continued to be the attention it attracts. After people on the ground see a skywriting message begin to form, they are driven by curiosity to stop and watch. Advertisers hire skywriters to create messages over beaches, fairgrounds, racetracks, and anywhere else they are guaranteed a large audience for their messages.
In skywriting, both timing and planning are crucial. Paraffin or some other nonpolluting oil-based fluid is vaporized in the 1,500-degree heat of the aircraft engine to create white smoke, which is then discharged under pressure. Letters are drawn at slightly different altitudes, which allows pilots to see what they have already drawn as they proceed. This method also allows pilots to complete their message without disrupting the letters already in place. Pilots will often use roads or railroad tracks to ensure that their skywriting follows a straight line. Letters average 1 mile high, and, on a clear day, they can be seen from a distance of up to 30 miles away. Depending on the weather conditions, skywriting messages will remain in the sky for up to twenty minutes.
Skywriting is performed at altitudes ranging from 7,000 to 17,000 feet, depending on temperature. On warm days, skywriting must be done at higher altitudes, because the temperature drops 3.5 degrees for every 1,000 feet of altitude. Each letter takes approximately twenty seconds to create. Skywriting works best in a cloudless sky with no more than a moderate wind.
A modern version of skywriting is called skytyping, in which five to seven planes fly in parallel across the sky in perfect unison. The message is written as smoke generators in each plane produce short, sharp puffs that expand after they are released, leaving a continuous line of dots in the sky. Using a master control panel in the lead plane to synchronize the smoke generators, the vapor is released in specific sequences, creating the letters in much the same manner in which dot-matrix printers create images on paper.
Brown, David. “Big Ads in the Sky.” Westways 78, no. 1 (January, 1986): 34-37. A brief article on the modern use of skywriting in advertising. Klemin, Alexander. “Handwriting on the Sky.” Scientific American 128 (May, 1923): 323. A classic article about early use of skywriting in advertising, describing the chemical processes and techniques involved. McConnell, B. M. “Story of Skywriting.” St. Nicholas 55 (April, 1928): 439-441. An early article about the history and technique of skywriting. Patiky, Mark. “Smoke Signals.” Air Progress 46 (April, 1984): 41-49. An illustrated article about skywriting.
High-altitude flight
Weather conditions
A skywriter leaves a reminder of the holiday, Valentine’s Day, above downtown Los Angeles, California. Skywriters use a special paraffinbased additive in their exhaust to create long-lasting smokelike letters or shapes in the sky.