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Ornithopters - Realistic Appearance

From the beginning, ornithopter designs often followed the overall shape and appearance of a real bird. Perhaps it was thought that the functional requirements would be more easily met in this way. It wasn't long before the effort to achieve a more realistic appearance took on a life of its own.


  		         Erich von Holst experimented with various bird and dragonfly ornithopter configurations in the 1930s. His work included experimentation with biplane wing phasing and hinged outer wing panels. Some of his rubber-powered ornithopters achieved a very high level of realism. I don't think anyone, to this day, has equalled the accomplishments of this artist and inventor.
 

Percival Spencer's engine-powered Seagull ornithopters, built around 1958, had fiberglass body shells and wings decorated to make them look more like a real bird. These mostly cosmetic features went a long way to achieving a high level of realism in the air.

A toy flying bird has to look like a real one. The Tim Bird was developed by G de Ruymbeke of France and introduced in 1969. It is the most successful toy ornithopter of all time and still in production. It functions like other rubber-band-powered ornithopters. The realism in achieved, as in the Spencer Seagulls, through the use of a hollow body shell and decorated wings.
 

        


 


 


 
        

Ken Johnson's Butterfly is another example of realistic styling. It can be fun to decorate the wings of your ornithopter more a more colorful and lifelike appearance. (Robert Eskridge built this particular model from Johnson's plans.)

 

 

  		  Albert Kempf went beyond decoration with his dragonfly model pictured here. The wings are made of foam, departing drastically from the conventional construction methods for rubber-band-powered ornithopters. This functional change allowed a much more realistic-looking wing. Kempf also broke from tradition by using a gear reduction in this rubber-powered ornithopter.
 

  		  Erich von Holst achieved a more realistic flapping motion by incorporating a flexible wrist joint in his ornithopter wings. This was taken a step farther in Nathan Chronister's modified Tim Bird shown here. The outer portion of the wing actually overlaps the inner part, as feathers overlap in a real bird's wing. This allows the wing span and area to be decreased during the upstroke, in order to reduce air resistance. This seemingly desirable feature has not been widely used in ornithopters because it is difficult to implement. Most attempts result in decreased performance.
 

Paul MacCready's 1986 half-scale replica of the pterosaur Quetzalcoatlus northropi achieved new levels of realism. This ornithopter not only looked like a real pterosaur, it demonstrated active stabilization methods like those used by birds and other flying animals. An onboard computer had to keep adjusting the position of the head, to keep this ornithopter from going into a spin. With its large head acting as a forward rudder, the actual pterosaur must have made similar corrections to stay airborne. The ornithopter's flight path was controlled by radio.
 

        


 

  		        

Some applications for ornithopters rely on their resemblance to real birds. In 2000, Intercept Technologies began using radio-controlled ornithopters for bird control. Styled to look like birds of prey, the ornithopters were used to chase flocks of birds away from airports, where they pose a threat to aircraft. Known as the Robofalcon, this ornithopter was based on Sean Kinkade's 1998 Skybird radio-controlled ornithopter kit. Internal-combustion and electric versions were used.

Another RC ornithopter, painted to look like a hawk, was used by the Colorado Division of Wildlife. The biologists wanted to band individuals of the Gunnison Sage Grouse to learn more about their behavior and find out how to protect this endangered species. The birds will not take flight if a hawk is nearby. Flying the hawk ornithopter overhead caused the birds to remain on the ground so they could be captured for study.