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Sunday, 9 October 2011
Gliding Vine Seeds inspires aerodynamicists
Alsomitra macrocarpa, known as the Alsomitra vine or the Javan cucumber is “a type of climbing gourd.”
The vine is found mainly in the forests of Java, Indonesia. Where it grows truly remarkable seeds by the hundreds in “football-sized pods.”
What makes these seeds so remarkable is the fact that they are virtually aerodynamically perfect gliders. Each seed has a set of “paper-thin” wings that can support the seeds minimal weight with the slightest breeze. The wings allow the seeds to travel hundreds of meters through the forest and once the seed lands, the wings rot away.
This remarkable evolutionary adaptation allow the seeds to disperse all throughout the Indonesian forest. Each seed now has a greater chance to develop into a fully grown vine because they aren’t competing with other vines for nutrients and sunlight.
The excellent aerodynamic properties of these seeds invoked two Japanese engineers, Akira Azuma and Yoshinori Okuno, to study the plant over 20 years ago.
The engineers discovered that the seeds glided with an angle of 12 degrees. This means that the seeds fall only 0.4 meters per second. These seeds truly have the best aerodynamic capabilities of any winged seed.
Decades before the two Japanese engineers calculated these figures, the excellent aerodynamic properties of the seeds were noticed by a man named Igo Etrich. Igo Etrich was an Austrian born flight pioneer who specialized in fixed-wing aircrafts around the turn of the century. Igo was inspired by the seeds, not of the Alsomitra vine, but of a very similar plant called Zanonia macrocarpathat possessed very similar seeds. In 1903, Igo developed some of the worlds first gliders using a shape very similar to the Alsomitra seed.
It is also believed that the shape and aerodynamic properties of the Alsomitra seed also inspired the Horten Brothers to develop the first “flying wing” aircraft, known as the Ho 229 for Nazi Germany in 1944. It was the first tailless fixed-wing aircraft to be powered by a jet engine. The shape of the seed lent itself very well to the design of this aircraft because it cut down on parasitic drag, or the drag caused by moving an object through a gaseous or fluid medium. It cut down on drag because it eliminated the need for a tail and it had a very shallow wing design.
This is a case where nature greatly inspired pioneers of human flight and a few little seeds helped change the world. >>>>> courtesy Professor Lorena A Barba