In 1909, Guglielmo Marconi was awarded a Nobel Prize for his development of radio. From this point on, the history books began to refer to him as "the father of radio." In fact, radio had many inventors, not the least of which was Nikola Tesla. But Marconi was now a wealthy man and Tesla was penniless.

"My enemies have been so successful in portraying me as a poet and a visionary," said Tesla, "that I must put out something commercial without delay."

In 1912, Tesla tested a revolutionary new kind of turbine engine. Both Westinghouse Manufacturing and the General Electric Company had spent millions developing bladed turbine designs, which were essentially powerful windmills in a housing. Tesla's design was something altogether different. In it, a series of closely spaced discs were keyed to a shaft. With only one moving part, Tesla's design was of ideal simplicity, much like the AC motor he had invented years earlier. Fuels such as steam or vaporized gas were injected into the spaces between the discs, spinning the motor at a high rate of speed. In fact, the turbine operated at such high revolutions to the minute that the metal in the discs distorted from the heat. Eventually, Tesla abandoned the project.

With no great prospects to speak of, Tesla began visiting the local parks more often, rescuing injured pigeons, and often taking them back to his hotel room to nurse them. Years later, when he lived at the Hotel New Yorker, he had the hotel chef prepare a special mix of seed for his pigeons, which he hoped to sell commercially. Naturally, this prompted speculation about his mental well-being. His aversion to germs also heightened in this period, and he began to wash his hands compulsively and would eat only boiled foods.

In spite of his growing eccentricity, fruitful ideas continued to spring from his imagination. At the beginning of World War I, Tesla described a means for detecting ships at sea. His idea was to transmit high-frequency radio waves that would reflect off the hulls of vessels and appear on a fluorescent screen. The idea was too far ahead of its day, but it was one of the first descriptions of what we now call radar. Tesla was also the first to warn of an era when flying vehicles without wings could be remotely controlled to land with an explosive charge on an unsuspecting enemy.

In 1922, at sixty-five years of age, Tesla still dressed impeccably. Yet friends observed that his clothing, like his scientific theories, now appeared old-fashioned. He managed to make a living by working as a consulting engineer, but more often than not he delivered plans that his clients deemed impractical.

During this period, Tesla spoke out vehemently against the new theories of Albert Einstein, insisting that energy is not contained in matter, but in the space between the particles of an atom.

In the late 1920s, Tesla began to develop a friendship with George Sylvester Viereck, a well-known German poet and mystic. Though nearly a recluse, Tesla occasionally attended dinner parties held by Viereck and his wife. Competitive by nature, Tesla wrote a strange poem that he dedicated to his friend. It was called "Fragments of Olympian Gossip" and poked vitriolic fun at the scientific establishment of the day.

Tesla's business with the U. S. Patent Office was still not finished. In 1928, at the age of seventy-two, he received his last patent, number 6,555,114, "Apparatus For Aerial Transportation." This brilliantly designed flying machine resembled both a helicopter and an airplane. According to the inventor, the device would weigh eight-hundred pounds. It would rise from a garage, a roof, or a window as desired, and would sell at $1,000 for both military and consumer uses. This novel invention was the progenitor of today's tiltrotor or VSTOL (vertical short takeoff and landing) plane. Unfortunately, Tesla never had the money to build a prototype.