How Does Skywriting Work?

Ever since the 1939 movie The Wizard of Oz came out, with the wicked witch writing SURRENDER DOROTHY OR DIE in the sky with her broom, sky writing has fascinated people. (That film message was really done with special effects in a 6 foot by 6 foot glass tank.) Sky writing goes back further than that, to 1922 in England. That same year advertisers began using skywriting and it became famous by Pepsi-Cola who used it from 1931 to 1953.

Are the letters really formed by smoke? Yes, skywriting smoke is made by inserting paraffin oil into the exhaust of the plane. The oil vaporizes in the heat making an environmentally friendly white smoke that lingers in the air. Of course, the pilot only injects the oil into the exhaust when he is in a position to form part of a letter.

The letters are generally a mile tall and the full message sometimes fifteen miles long. The letters can only be seen for perhaps twenty minutes before they drift to deformity so the message must be written quickly. Many factors determine the success of the mission. First the pilot must be skilled. He at times must fly upside down to get his letters formed. Second, the plane must be powerful enough. Not only does the plane need to be very maneuverable, but it must also be hot enough to vaporize sufficient paraffin oil to make the smoke. To do this 1500 degrees must be reached. Some recommend 450 horsepower engines that 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.

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.

Remember too that the pilot is writing from the top, horizontally, that is, parallel to the earth. Therefore he must write the letters backwards so that they appear correctly to the readers below. They must also be relatively the same size and in a straight line so that the message is readable. All this takes great skill.

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 is the cost for skywriting? This depends on the company, and availability. If you must fly a skilled pilot from some distance, the cost of transportation could be greater than the message writing itself. Generally for local skywriting, prices start around 00 and multiple messages are discounted.