The History: Wilbur replied to Chanute's letters from September 12th and September 18th. Wilbur communicated to Chanute that he and Orville have been extremely busy with last minute preparations to depart for Kitty Hawk next week. They shipped all of their remaining materials yesterday.

Captain Ferber wrote "a very nice letter" to Wilbur a few weeks ago before Ferber departed for the sandy hills on which he planned to glide. From Chanute's description, Wilbur is sure that the wings of Ferber's machine have too much curvature and the ribs used to define the shape of the wings' surfaces are not holding the needed shape. Wilbur also speculates that Ferber's front rudder may not be responsive or accurate in movement.

1902 Wright Glider Over Kill Devil Hills The Ribs Run From The Front To The Back Of The Wings

Wilbur is glad to hear that Patrick Alexander from England may be visiting. The Wrights will be extremely busy at their camp this year. Consequently, Wilbur and Orville have agreed that only Chanute and Dr. George Spratt will be invited to their camp this year. However, the brothers both like and enjoy Alexander and he will be welcome to visit their camp.

Wilbur thanks Chanute for the offer of using his cups and plates, but feels they have everything in order. If needed, they can buy supplies in North Carolina.

Examine the airfoil (wing shapes) in our gallery (Gallery 1, Gallery 2). Wilbur and Orville designed and tested these shapes for their 1901 wind tunnel tests. These tests determined the amount of lift and drag different wing shapes could obtain and subsequently the best wing shape for their flying machine. Some of the shapes are very curved like Airfoil #30. Others have a shape like a bird's wing (Airfoil #35). Other shapes, like Airfoil #12, have a smaller gradual curvature. (Airfoil #12's shape was used on the successful 1903 Wright Flyer.) Note that these small airfoils are made out of metal which retains its shape, even in wind.

Airfoils #30, #12 and #35.

In contrast, examine photos of the first flying machines. The wings' covers are made of fabric and the fabric retains its shape by wooden ribs and spars. In Ferber's case, Wilbur believes Ferber used too deep a curvature and in addition the ribs did not provide enough support to retain the proper wing shape.

The Wings Of Early Flying Machines Were Made Of Fabric And Wood

As manufacturing techniques for metals improved in the early 1900's, metal rods and pieces began to replace the wooden components in airplanes. Metal skins, rolled very thin, were used because they were less affected by weather than the fabric skins. The ribs and spars of the plane were made by riveting many pieces together. When aluminum alloys became available at the end of the 1920's, these pieces were often stamped out whole from aluminum sheets.

Quotation from the book The Papers of Wilbur and Orville Wright, Volume 1 by M. McFarland.