In 1971, Lieutenant Pickott, a retired British Air Force pilot, copied Kelly's glider from a note he had left behind, and in 1973 he performed live for a television audience,2 thus proving that Kelly's account was true more than 100 years ago.
About half a century after Kelly's death, the Wright brothers, the younger brother Orville Wright and the older brother Wilbur Wright, fulfilled his last wish - self-propelled manned flight. Orville Wright said in 1912 that their success was entirely due to the English gentleman's theory of flying machines.
He said: "Sir George Kelly laid out the principles of aeronautical science without precedent or since, and until the end of the nineteenth century he published works which are infallible and are indeed the greatest documents in the history of science." And his brother Wilbur Wright also said, "When we designed the plane, we did it entirely by the very precise calculation method that Sir Kelly had proposed." ”
After Kelly, the second generation of aircraft inventors was represented by Otto Lilienthal of Germany. Unlike Kelly, Lilinthal was primarily a practitioner rather than a theorist, and he was the first person in the world to realize self-powered gliding flight, and he was also the first person to successfully repeat gliding experiments, but Lilinthal's working methods had a natural flaw, that is, the theoretical research and preparation work were not sufficient, and he relied too much on manned flight tests. Unfortunately, Lilinthal died in one of the trials. However, his work was very inspiring to the Wright brothers, and his deeds inspired the work of these two young Americans. Today, there are still many Germans who believe that Lilinthal was the first to invent the airplane, and an airport in Berlin is named after him.
Compared to Kelly and Lilienthal, the Wright brothers, the third-generation inventors, were much luckier. They were born late enough that Kelly's theories and Otto's internal combustion engine were ready for them. They were born early enough that airplanes have not yet been invented. Of course, luck alone could not build the first airplane, and the Wright brothers comprehensively surpassed not only their predecessors, but also their contemporaries in terms of theoretical accumulation and working methods.
The Wright brothers paid great attention to the theoretical correctness of the design of the aircraftAlthough the two of them are self-taught, they have systematically learned aerodynamics, have a solid theoretical foundation, and are very rigorous in their work. The brothers later discovered that Lilinthal had calculated lift by 60% more than 60 percent and corrected it, which was later verified by experiments. This is a big reason why they were able to succeed and Lilinthal failed.
In the design of the aircraft, the Wright brothers' greatest contribution was the invention of the joystick that controls the wing of the aircraft, which fundamentally solved the problem of aircraft control. Before that, Kelly was unaware of the problem because the problem of power had not been solved at that time, and Lilinthal was aware of the control problem but did not find the answer.
Therefore, it is completely impossible to try to get the pilot to balance the aircraft by the movement of the body, like a bird. At this point, the three most critical technologies for building an aircraft are in place. The lift problem was solved by Kelly, the power problem was solved by Otto, and the control problem was solved by the Wright brothers.
The Wright brothers are most noteworthy for their methods of working beyond other inventors of their time, building a wind tunnel in which a large number of experiments were carried out in order to test the lift and control systems of the aircraft. In order to improve the wing, the Wright brothers tried more than 200 different wing shapes and tested them thousands of times. They connected the weights and the wings of the aircraft with pulleys to accurately calculate the lift in various conditions. In addition, they conducted extensive experiments on how to control the aircraft's aeromaneuvers such as balancing, pitching, and turning. Therefore, when the first aircraft they designed was tested for flight, they were sure that the aircraft would be able to fly and that it would be well stabilized laterally.
The Wright brothers are cautious by nature, they will not test the flight without doing enough tests, and even if they do, they must first conduct an unmanned test flight. To test the steering control of the aircraft, the Wright brothers conducted 700 1000 glide tests in 1902. The glider they built was tested hundreds of times with a controllable tail rudder installed, and all of these tests showed good maneuverability, with the longest one lasting 26 seconds and flying 1897 m (622.)5 feet).
On October 8 of that year, the Wright brothers achieved true flight steering control, an important milestone in flight history. After more than a year of hard work, the Wright brothers successfully flew their own Flyer 1 in Kitty Hawk Town on the West Coast of the United States. Since then, mankind has entered the age of airplanes.
Around the time of the Wright Brothers' invention of the airplane, inventors from all over the world were accelerating the development of airplanes, but there were not many successful ones, and many inventors (including China's aviation pioneer Feng Ru) still paid the price of their lives even after the Wright Brothers' airplane was launched, mainly because the working methods lagged behind the Wright Brothers. Until today, the research and manufacture of aircraft is still an extremely complex matter, and a large amount of information needs to be obtained through experimentation before it is possible to design an aircraft that can fly safely and effectively. The Wright brothers had gained enough information by conducting a large number of safe, non-manned test tests that by the time they actually began manned tests, their aircraft was much safer than the prototypes of their contemporaries.
The Wright brothers' early evidence of a successful test flight was only taken by photographers** (including one taken inadvertently by a photographer on the beach), so many people are still skeptical: it wasn't until 1908, when the Wright brothers conducted several successful flight tests in public in Europe and the United States, that the world turned from skepticism to admiration. In 1909, Taft invited the Wright brothers to the White House and honored them.
Five years later, the First World War broke out, and the needs of war greatly accelerated the development of aircraft. After the war, airplanes began to be used for civil aviation, and its first stage of rapid development turned out to be the Great Depression in the West in the 30s of the 20th century. The second peak of the development of civil aviation was in the 20 years after World War II, when aviation technology developed for war purposes was used in civil aircraft, and at the same time, a large number of pilots and mechanics of retired fighters were added to civil aviation services. In 1949, de Havilland built the first jet airliner, the Comet, while the Boeing 707 became the first jet to be widely used by countries around the world, while the old propeller aircraft could only be committed to short-haul, low-volume routes.
In 1969, the Boeing 747 flew successfully, and it subsequently became the flagship aircraft for intercontinental flights around the world. In the same year, the British-French supersonic Concorde was also successfully tested, and in 1976-2003 more than 1 4 centuries provided transatlantic supersonic passenger flights.
Since the 70s of the 20th century, human progress in various means of transportation has been in a state of relative stagnation until the rise of electric vehicles at the end of the 20th century and the emergence of driverless cars after entering the new century.