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Chapter
1
History of UAS: Where did they come from and where are they headed?
Although unmanned aircraft may seem like a relatively recent development, these systems have been in use for quite some time, dating back to as early as the late nineteenth century. Many of the technologies and principles required for operation of modern systems were first envisioned, uncovered, and developed by various scientists and inventors in these early eras. This chapter contains an examination and discussion of crucial pioneers of technology and aeronautics, periods of technological development and operational expansion, the changing role in the modern era, and the technological and regulatory landscape influencing application of unmanned aviation.
Early Predecessors
Early aeronautics pioneers and their precursor models and technologies eventually led to the development of early unmanned aircraft, which were used for a range of functions, such as aerial research platforms, weapons, and targets. While the list of contributors to the success of unmanned aircraft provided here is not exhaustive, it does highlight some of the significant research and experimentation that has led to the technologies necessary to successfully operate such unmanned systems.
Born in 1773, Sir George Cayley was an early pioneer of aeronautical vehicle design and aerodynamics research. In 1804, he designed a monoplane glider that appears sophisticated even by today’s standards. Cayley is credited with discovering that curved surfaces generate lift more effectively than flat ones. Also, he found that some modifications to wings, such as canting them upwards (commonly referred to as dihedral), added stability to his aircraft. In 1849, he created a glider with space for a pilot, which he successfully flew with a young boy as the occupant. Several years later, Cayley built a larger glider, which also successfully flew (see Figure 1-1). Cayley’s discoveries provided essential foundations for aircraft design and aerodynamics theory.
John Stringfellow, born in 1799, was fascinated with machinery, in particular with carriages and steam engines. Stringfellow experimented with light steam engines in an effort to propel aircraft designs developed by fellow aviation enthusiasts of the time. By 1848, he had worked to create an aircraft with counter-rotating “propellers” driven by a lightweight steam engine. After several failed attempts, he was able to properly balance the aircraft, resulting in a successful short-distance flight with the ship being guided by wires. Stringfellow’s work demonstrated the importance and utility of adding reliable propulsion to aircraft (see Figure 1-2). His foundational work would inspire those who followed his efforts.
By age 21, Alphonse Pénaud had established himself as an accomplished aviation inventor, demonstrating one of his early flying inventions in Paris in 1871. Credited with harnessing the power of rubber bands to power aircraft propellers and rotors, Pénaud’s designs reliably and successfully flew with ease (see Figure 1-3). Pénaud’s work is credited with inspiring the Wright brothers early in their lives. In 1876, he developed a sophisticated amphibious aircraft including seemingly modern flight controls and instrumentation with the help of other aviation enthusiasts, but this design never moved forward. The works of Pénaud certainly were influential to future aircraft experimenters.
Born in Prussia in 1848, Otto Lilienthal went on to study engineering, leading him to the design of numerous successful gliding aircraft. First experimenting with kites, Lilienthal began to work with different shapes of wings to determine which was the most utilitarian for flight. Most notably, in 1890, Lilienthal began working diligently on flying machines that allowed for the carriage of a pilot. The initial iteration of Lilienthal’s glider was flown in 1891 and achieved a flight of approximately 80 feet. By the next year, the distance capability of his revised glider was doubled, and Lilienthal began work on a derivative that used a motor to flap its wings. Lilienthal worked diligently to better understand flight through repeated tests of his works. He was able to successfully fly his numerous models in more than 1,500 total flights, eventually reaching distances of nearly a quarter of a mile (see Figure 1-4). By the time of his death in 1896, he had published numerous articles about flight and his endeavors, which were noted by the Wright brothers years later as inspirational to their work.
Nikola Tesla fulfilled a peripheral, yet critical, contribution to the advent of modern unmanned aircraft. While not directly associated with the development of aircraft as were Lilienthal, Cayley, and Stringfellow, Tesla developed electrical components essential to the creation of the modern radio. Born in 1856 in Smiljan (modern day Croatia), Tesla went on to study math and philosophy in Graz (Austria) and Prague (Czech Republic), respectively. At age 26, Tesla devised the concept of a brushless alternating current (AC) motor. Tesla then moved to New York and began to work with Thomas Edison, making improvements to Edison’s direct current (DC) designs. Within a few years, Tesla began his own company, which eventually led to the adoption of an AC power grid in Massachusetts. This began a competition of sorts between Tesla and Edison as to the future power supply, pitting Tesla’s AC power against Edison’s DC. In the 1890s, Tesla created a variety of electrical component inventions and improvements including his namesake transformer, the Tesla Coil. He was also able to demonstrate radio communications years before Marconi. In fact, some of Marconi’s patents would later be cancelled as a nod to the true originator of the concepts. Tesla used this type of communication to control a model boat in a demonstration in New York City. This last feat truly laid the foundation for future remote control on which current unmanned systems rely. Also, Tesla’s legacy of AC power transmission is still the source of choice for the developed world.
Guglielmo Marconi was born in Italy in 1874. By age 20, he was already interested in the works of Heinrich Hertz, in particular the use of radio waves. Marconi soon developed a means of transmitting messages through the use of such waves from up to a mile away. In 1896, he moved to England and within a year developed a wireless station used to communicate with ships over 10...
