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About this Article
Written by: Albin Cheenath
Written on: October 1st, 2002
Tags: aerospace engineering, sports & recreation
Thumbnail by: Dembinski/SXC
About the Author
At the time of publication, Albin Cheenath was a junior majoring in Computer Engineering and Computer Science at the University of Southern California.
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Volume I Issue II > Engineering Kites Beyond Flight
Kites have existed for thousands of years, but even today, little is understood about them. While the aerodynamics of a kite are known in theory, in practice deformability makes its behavior highly unpredictable - yet, precise control of kites has rarely been a concern since kite flying has been relegated to the hobbyist's realm. The past decade has seen a revival of interest in kites due to new kite-based sports, novel commercial applications, and scientific uses of kites. As a platform for different activities, kites are attractive due to their low cost, portability, and easy maintenance. This renewed demand is pushing kite-makers to mass-produce and thus develop the science and engineering of kite production on a new level of sophistication. The role of engineering in kite making has led to several innovations and discoveries in aviation science and has shown that there is much to be grasped and many inroads to be made in this field.

Introduction

In 1826 an English schoolmaster named George Pocock patented an unusual invention: a carriage drawn by kites that could travel at about 20 miles per hour. Wherever it went, the carriage baffled and amazed people. A more significant perk resulted from the toll fee conventions of the time - since a carriage was charged according to the number of horses pulling it, Pocock paid nothing for his kite-drawn vehicle [1]. Such innovative kite usage contrasts with the conventional image one envisions of young children tugging at their little kites.
Kites are highly complex, belonging to the class of deformable flying structures that are more difficult to control than rigid flying structures, such as airplanes. The deformation of such objects alters the flying characteristics, thus leading to difficulties in maneuvering. Consequently, the way in which the flying object is controlled needs to be continually readjusted. Currently, one cannot predict the way in which the object will deform in response to continually changing factors in the environment, like wind and temperature. There is much to be learned about kites, and the work of engineers reveals the potential possibilities.
Dembinski/SXC
Figure 1: Although most commonly seen in recreational settings, kites also have relevant commercial applications in other fields.
Despite the prevalence of kites through the centuries and in many cultures, not much is understood about them. Even when kites were used for highly sensitive or important work, their ability to soar and cover long distances was the main focus; precision control was unimportant. Though human lives often depend on other deformable objects, such as sails and parachutes, such was not the case concerning kites, so proper research was rarely conducted. While most commonly seen in recreational settings, kites are capable of and have been used in much more influential endeavors, serving as the launching pad for several revolutionizing discoveries and technologies (Fig. 1).

A Short History Lesson on Kites

If it weren't for kites, Wilber and Oliver may never have invented the airplane - the brothers originally explored the idea of creating a flying machine by testing many kite designs. Their final airplane design was based on the box kite invented by an Australian scientist, Lawrence Hargrave [2]. Their belief that successful human flight could utilize the elements of kite design set them apart from the numerous would-be inventors. Benjamin Franklin's famous lightning experiment using a kite also exemplifies the way in which kites allowed scientists to conduct experiments at high altitudes.
Kites also played an important role during World Wars I and II, in which the French used them to quickly detect enemy movements, and the U.S. Navy implemented them for target practice. A Chinese general in the Han Dynasty used a kite to measure the distance into an enemy's fortress and built a tunnel that led him to a quick victory in battle; even the ancient Egyptians used kites to lift heavy loads when building structures [3]. Despite all this, kite usage has been limited in scope, and little scientific research has been done on them.