Wednesday, October 11, 2017

The World's Largest Signboard

When was the last time you read a Science and Mechanics magazine from 1937? Not lately? You missed an interesting article!

When was the last time you saw writing in the sky? Today, it seems to be more common to see planes towing banners.

Skywriting began after the First World War. A British war ace wrote DAILY MAIL over the Epson Downs racetrack during the running of the derby in 1922. In October of that year, an American wrote high above New York, HELLO USA CALL VANDERBILT 7200. That was the phone number of the Hotel Vanderbilt in New York. The switchboard was swamped for over five hours.
Skywriting is performed nearly three miles above the earth. Each letter is approximately one mile high, and writing a phrase may take eight miles. Each letter is written on either a higher or lower plane than its predecessor. When crossing a “T”, the cross bar is at least 50 feet higher. Otherwise, propeller wash blows away part of the work already completed.

Wind doesn’t break up skywriting. It carries the message along, intact. A message written over the Chicago loop was read in Michigan City an hour and a half later. Writing will be broken up by intermittent gusts or rising and falling air currents.

The pilot carries a chart showing him exactly where to turn on and shut off the smoke. The writing is done on a horizontal plane, rather than vertical, and is written backwards so it is readable from the ground.

In the days before computer assistance, skywriting seemed to be a sixth sense. Some pilots took to it like a duck to water. Others just didn't.


  1. Very interesting article. I'm still thinking through the fact that it was written backwards so people could read it from the ground. HMMM.