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Guide Index

The Eternal Wing

Taking to the Air

Cockpit Confusion

Bird Man


Viewer Challenge
in the classroom


As you see on Frontiers, Dr. Ken Dial and other researchers at the Flight Laboratory of the University of Montana are experimenting with new and novel techniques to better understand bird flight. Earlier studies of bird flight had to rely on dissections and external examinations, but current research may ultimately lead to improvements in aircraft design.

Though most schools do not have access to the high-tech equipment Dial uses, some of his experiments can be simulated using an inexpensive ornithopter model called Tim Bird. The bird is powered by a rubber band and is said to be capable of flights of 150 feet. The first two activities for "Bird Man" make use of the model.

Materials for Activities 1 & 2:

  • Tim Bird (see ordering information below)
  • video camera
  • paper
  • pencil

Materials for Activity 3:

  • rubber-band-powered balsa wood gliders
  • sandpaper
  • glue/hot glue gun


These activities will help students understand and demonstrate principles of flight.

To Order the Flying Tim Bird:

Contact the Edmund Scientific Company, 101 East Gloucester Pike, Barrington, NJ 08007; phone 609-547-8880. Stock number is S42,720. The cost is $8.95 plus shipping and handling.


Dr. Ken Dial and his associates have studied European starlings using cineradiographic (movie x-ray) equipment as the birds flew in a variable speed wind tunnel. Among other findings, they discovered the important role the wishbone (the fused collar bones or clavicles) plays in a starling's flight. The bones act like a spring, capturing part of the energy of a wing's down-stroke to help with the following upstroke.

bones Procedure:

  1. Wind up Tim Bird and, while holding it, observe the flapping movement of the wings. Draw a hypothetical model of the mechanism inside the toy bird that makes the wings flap and explain how it works in writing.

  2. A hole in the neck of the bird provides a view of the workings of the wings. Draw these workings and compare to your drawing in No. 1. If it is different, analyze whether or not the hypothesized model would have worked.


Beginning with Leonardo da Vinci, scientists have tried to analyze how birds fly and to design machines that imitate this movement. Although da Vinci observed birds carefully and made many drawings, he never totally understood how birds use their wings to lift and propel themselves through the air.

Around the year 1500, da Vinci sketched a design for a flying machine with flapping wings, which he called an ornithopter (from two Greek words: "ornithos," or bird, and "pteros," meaning wing). Bird flight was much more complicated than even da Vinci realized, and he lacked the materials and technology needed to make the machine leave the ground.

Not until 1870 was the first successful flight of an ornithopter reported, when Gustav Trouve flew a model powered by exploding cartridges for 60 meters. An earlier version of Tim Bird (an inexpensive ornithopter; see ordering information in "Understanding Bird Flight") was sold as a toy in Paris in 1879.


  • Wind up Tim Bird and examine how it works by allowing its wings to flap while it is being held. Note any air movement around the bird.

  • Use a video camera to tape the motion of the wings as they flap while the bird is being held. Make sure to get front, side and back angles.

  • Videotape the bird flying in an open area. Make views of the bird as close up as possible.

  • Play back the videotape at slow speed, perhaps one frame at a time.

  • Analyze the motion of the wings, especially the movement of the mylar material of the wings, to determine where the bird gets its lift and forward movement.

  • Remove the tail to determine what role it plays in Tim Bird's ability to fly.

  • The upward movement of an ornithopter's wing uses less energy than its downward movement, which results in an uneven movement of the wings. Attach a small rubber band under the bird's belly that connects the base of each wing, to assist with the downward movement of the wings. Fly the bird to compare flights with and without the assist. The rubber band should make the downward movement more efficient.

  • Tim Bird's instructions show that an adjustment to the tail will cause the bird to turn in different directions. Experiment with adding weights to the wings or the body to see their effect on the bird's flight.


Computer-assisted flight control makes it possible for pilots to fly planes capable of much more sophisticated flight maneuvers, imitative of the complex flight movements of birds. The shape of the airplane and its wings may even change in the future.


  1. Divide into teams. Each team should have a rubber-band-powered balsa wood glider, available at most toy and discount stores.

  2. Add hot glue to the body or wings of the plane, or remove materials by sanding parts of the plane in order to construct a plane that can do one or more of the following: make accurate long flights; fly in a loop; make a banked turn and a smooth landing; and/or make other acrobatic maneuvers.

  3. Demonstrate the flight to others in the class.

  4. Write a report describing the changes that were made and their effects on the plane's flight.


For more information about ornithopters...
  • Watch the short NASA film "Aeronautical Oddities," available from NASA CORE, 216-774-1051, for $15 plus $4.50 s/h.


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.