The History: Orville's personal diary tells us the brothers each worked 10 hours today. They decided to straighten one end of the upper surface. The 1901 glider was dismantled and its uprights (the boards which separated the upper and lower surfaces) installed in the 1902 glider. Wires were stretched diagonally between the upper and lower surfaces to act like trusses.

Components of the 1902 machine were weighed. The upper surface weighed 36 pounds. The upper and lower surfaces including the uprights, wires and a few hinges weighed 87 pounds.

Below is a picture of Orville Wright flying the 1902 glider just above the sand at Big Hill. Do you see the uprights? The Wrights installed these today. (This picture was taken on October 10, 1902 - about a month from now.)

Orville Wright Flying In the 1902 Glider

Trusses are used to form a rigid framework. Trusses are a network of beams, wires or other materials which support, strengthen or stiffen a structure. Trusses are used in roofs, bridges and were used on the Wright's flying machines. Since the Wrights used thin wires for their trusses, the wires are difficult to see.

Truss Bridge Worcester, UK Photo Courtesy Dr. Derek Locke, Bridge Building (http://www.brantacan.co.uk/bridges.htm)

Here is a photograph of one of our Wright Again glider models. Do you see the wires? What do you think the glider's wings would look like without the wires? How do you think the glider would behave without those trusses?

Wire Trusses