The movie The Wizard of Oz, a smash hit when it came out in 1939, had a scene where the wicked witch wrote SURRENDER DOROTHY OR DIE in the sky with her broom. Ever since sky writing has fascinated people. (The witch’s message was actually just special effects, produced in a 6 foot by 6 foot glass tank.) But sky writing goes back further than that. It was first tried in1922 in England. Advertisers began using skywriting at the same time but Pepsi-Cola made it famous, using skywriting from 1931 to 1953.
Skywriting smoke is made by shooting paraffin oil into the exhaust of the plane. As it heats in the exhaust, it produces an environmentally friendly smoke that forms the letters. Of course, the pilot doesn’t want the smoke to appear continually. He must decide just when to turn it on or off so that part of a letter is formed.
The letters are about a mile tall and the message may be as long as fifteen miles. The drifting smoke only retains a letter for at most 20 minutes so the message must be written quickly and without mistakes. There is no such thing as a smoke eater to erase mistakes! The success of the mission is determined by several factors. First the skill of the pilot. He must be both skilled and artistic. Second, the plane must have sufficient maneuverability and power. The power is partly needed to produce sufficient heat (1500 degrees) to vaporize the paraffin oil. Some recommend planes with at least 450 horsepower engines because they are six times hotter than small plane engines.
Of course for flying weather is a major factor. The sky must be nearly clear to see the white letters against the blue sky. The wind cannot exceed three to five miles per hour. The letters are therefore formed somewhere between 7000 and 17000 feet, wherever it is cool enough and windless enough. The cooler air temperature is better for making smoke, but it cannot exceed 95 degrees. When all is just right, message can normally be seen for thirty miles on either side. These perfect conditions are most predictable in September or October.
Messages are usually four to six letters long and each one takes one or two minutes to form. A shorter message is more likely to be visible at once. When a message is longer than this, then the first part may be gone by the time the last part is formed. One remedy for this is to get multiple planes involved. When two or three pilots coordinate their maneuvers, they can produce the message visible in its entirety for a few minutes before it drifts away.
How large is the message? It is usually four to six letters and it takes one to two minutes to form each letter. A shorter message is more likely to be visible at once. Why not make it longer? When a message is longer than this, it will take too long to form so that it is seen all at once. One remedy is to hire multiple pilots. The two or three pilots coordinate their maneuvers so that, as they work together, they will produce the message visible for the minutes before it drifts away.
Who would benefit from using skywriting? After all, it is so unique that people would have a hard time NOT reading the letters as them form in the sky. Some who have benefited from skywriting are advertisements for websites, political candidates, motion pictures, soft drinks, and others. It is also used for novel announcements. Fifty marriage proposals are written in the sky each year by one company.
What does all this cost? The cost depends on the company, and on the availability. For example, if you must fly in a skilled pilot from some distance, that will add significant cost to the adventure. But for local skywriting, count on starting around $1000 and look for a discount if you get more than one message or the same message multiple times. Contact a company experienced in aerial advertising for more information.