I hope everyone is enjoying their Monday holiday and if you are working, like me, then perhaps there will be some comp. time in your future. Today I have a quick look back at navigation for the Air Mail pilots and how they conquered the trans continental route from coast to coast.
The United States Postal Service first made the arrows in 1924. Why did they make the arrows? In the early 1920s, airplanes hadn’t been around for very long and the Postal Service was experimenting with using airplanes to deliver mail. The Postal Service established routes along which to fly airmail. They called the routes “airways.” The Postal Service decided that pilots needed to be able to fly during both day and night to deliver the mail quickly. So they came up with the idea of building arrows and beacons.
They built the towers in the middle of the concrete arrows. These giant arrows were the foundations for electrical beacons. The postal service hired people to turn on the beacons every night to guide airmail pilots flying airways in the dark. These people were a lot like lighthouse keepers. How far apart were the arrows? They placed the beacons about every ten miles along an airway. The beacons or lights sat on top of tall steel towers, between 20 and 87 feet high. The beacons were two, very bright lights (1,250,000 candlepower). They ran on electricity and rotated so that a pilot would see flashes. They were only 10 miles apart so that when a pilot arrived at one beacon, he could see the flashes of the next.
Did the arrows all point the same direction? No. The arrows pointed towards the next beacon along the airway, so pilots could use them to stay on course during daylight hours. The towers and foundations were painted with bright colors (yellow and black or orange and white) so pilots could see them easily.
January 19, 2015