Thursday, June 1, 2017
The Art of Skywriting
The typical smoke generator consists of a pressurized container holding a low viscosity oil which is injected into the hot exhaust manifold causing it to vaporize into a huge volume of dense, white smoke. Wake turbulence and wind cause dispersal of the smoke causing the writing to blur and twist, usually within a few minutes.
However special "skytyping" techniques have been developed to write in the sky in a dot-matrix fashion with a new letter every 2–5 seconds instead of every 1–2 minutes which allows the message to remain legible for longer. In skytyping a computer program triggers the injection of fluid into the exhaust, not the pilot.
With skytyping there are no aerial acrobatics, but formation flying is required. The planes fly side by side, equidistant and at the same altitude. The letters are made up of individual dots that blend together at a distance. Emitting the dots is entirely automated. A message is loaded into a computer that controls the smoke and the program tracks the locations of each plane. Whenever a plane reaches a point where a dot should be placed the computer triggers a burst of smoke. The entire formation flies a predetermined distance, shifts position and then makes another pass to lay the next line of smoke dots. The passes continue until the message is complete. Obviously, this method is much more expensive.
The beginnings of skywriting are disputed. In a 1926 letter to The New York Times it was stated that skywriting was perfected in England in 1919 and used in the United States the next year. But stunt pilot Art Smith was known to do skywriting at the end of his exhibitions in 1915 when he wrote "Good night."
Skywriting dates back to World War I when a group of RAF pilots discovered that running paraffin oil through a plane's exhaust created a white smoke trail that would hang in the air. They used the smoke to signal ground forces when all other means of communication were unavailable and to create smoke screens for troops and ships.
After the war Captain Cyril Turner took what he knew about skywriting to the advertising world. The result was the first recorded use of skywriting for advertising purposes. It was over the Derby at Epsom Downs Racecourse in the United Kingdom in May 1922 when Turner wrote "Daily Mail" above the track.
Commercial skywriting in the United States was developed in the early 1930s by Sid Pike, president of the Skywriting Corporation of America in 1932. One of the first major clients was Pepsi-Cola, which used skywriting to reach a mass market. In 1940 Pepsi wrote some 2,225 skywritten messages over 48 states, Mexico, Canada, Cuba, and South America.
At one time skywriting was seen as the future of advertising and some claimed it was bound to be a bad thing. The New York Times called it "celestial vandalism" and claimed that in the future the skies would be so smoke filled that apartment dwellers on upper floors would have to keep their windows closed. There was even predictions of cloud slicing machines that would allow for skywriting in any weather and some engineers worked to develop smoke that would glow in the dark so messages could be written at night. Colored smoke was another prediction and some pilots tried it, but it never worked as well as white.
In 1946 the Skywriting Corporation had a fleet of surplus World War II planes and developed "dot matrix skywriting", or skytyping as it was called. Skytyping uses five planes in formation to choreograph puffs of smoke being released from each plane. The messages, written at 10,000 foot altitude, can be up to 1250 feet tall and over five miles long. Skywriting letters, on the other hand, are 3,000 feet high and take longer to write.
The rise of television in the 1950s put a damper on skywriting's ad appeal because television allowed companies to put their ads in customers' homes and match ads to target audiences regardless of the weather. Nowadays, it's just a novelty.
A single skywriting aircraft capabilities depend on the size of the smoke oil tanks. Usually up to 12 letters or characters. 30 gallon tanks are typical and it takes 2-3 gallons per letter. A six-plane digital skywriting formations can form up to 30 letters and can stretch four to six miles long. Usually though a single plane is used and the average message can be up to eight characters long.
How long the message remains visible depends. Winds are their nemesis. With no winds, skywriting is visible until the earth rotates away from the writing in about about an hour or so. If winds are strong, visibility of the skywriting can vary from a seconds to 5-10 minutes.
Costs typically start at about $3,500.00 per message, but ferry fees to move aircraft to the desired location will cost extra. The average cost for a personal message is $8,500.00 based on travel of one of the few aircraft that are located in the USA. Skywriters need blue skies and clients typically agree to pay rain or shine, so clients take a risk. One company advises that if you don't want to pay that much, or take the risk, then hire someone to tow a banner!
One source claims there are only four professional skywriters in the world. Skywriting is usually done at an altitude of 10,000 feet and requires looping, climbing and rolling all while releasing perfectly timed streams of smoke. In ideal weather conditions, skywritten messages can be seen for more than 2,800 square miles. If my math is correct, that would be a square about 53 miles by 53 miles.
The real question is how to they do it? In the past skywriting pilots were known to provide false information to throw off their competitors. The only way a pilot can learn how is from a current skywriter. Having all the right equipment, which includes a single-engine, high-horsepower plane and an $800 drum of liquid smoke, not to mention specific piloting skills isn't enough. Even skilled crop dusters and acrobatic pilots would hardly be able to learn it on their own.
Everything starts with a flight diagram that notes turns, where each letter begins and ends, how many seconds to count off from the top to the bottom of each letter and more. It requires split second timing down to how man degrees the turns must be. Because skywriters are writing horizontal to the ground they have to write backwards and are unable to track their progress visually - all they see is blue sky and smoke so the must trust their planning and their instruments. Headings have to be dead on...being even slightly off can make for a pretty bad looking letters that can ruin a message. They also have to be able to efficiently transition from one letter to another, knowing when to open and close the flow of smoke. They also have to ensure that each letter is proportionate to the others, evenly spaced and running along a straight line.