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Open Source Philosophy and the Dawn of Aviation In 1789, Laplace developed an equation that would help solve Euler’s equations. It is still used in Modern Aerodynamies and Physics. He also successfully calculated the speed of sound. In addition to these theoretical advancements, experiments in Aerodynamics were also producing more practical results. In 1732, the French chemist Henri Pitot invented the pitot tube, a device that enables the speed calculation at a point in a flowing fluid. This would help explain the behavior of fluid flow. The English engineer Benjamin Robins performed experiments in 1746 using a whirling arm device and a pendulum to measure drag at low and high speeds.

In 1759, English engineer John Smeaton also used a whirling arm device to measure the drag exerted on a surface by moving air. He proposed the equation D = kSV², where D is the drag, S is the surface area, V is the air speed, and k is a constant, which Smeaton claimed was necessary for it. This constant became known as Smeaton’s coefficient, and the value of this constant was debated for years. Those making the first attempts at flight, including the Wright brothers, used such coefficient. French scientist Jean-Charles Borda published the results of his own whirling arm experiments in 1763, and verified and proposed modifications to current Aerodynamic theories, being able to show the effect that the movement of one object had on another nearby one. The Navier-Stokes equations, which are considered the most complete mathematical model of fluid flow, were written in the beginning of the 19th century. However, this system of equations was solved only halfway through the 20th century. Therefore, Aviation pioneers largely used experimentation and employed less complex theoretical models in order to achieve their goals. As of the middle of 19th century, two new trends emerged based on the steam engine: the race to fly a lighter-than-air airship with engines and directional control, and the development of fixed-wing aircraft. Over time, the airplane began to take on a familiar shape.

In 1799, 26-year-old George Cayley sketched what it is now recognized as the familiar conventional configuration of an airplane: a cambered wing having dihedral; an aft vertical tail; and an aft horizontal tail. Cayley’s choice for the airfoil was based on their Aerodynamic characteristics tested by him and his predecessors using a whirling arm apparatus. He himself invented dihedral as a means for maintaining equilibrium in roll. The vertical tail provided directional stability, like the feathers on an arrow, and in Cayley’s view, would also be used for steering, as a boat’s rudder serves. By analogy, the horizontal tail gave stability in pitch. It turned out that Cayley was half right on both counts. He did not formally apply Newton’s laws for translational and rotational motions to the airplane. No mathematical descriptions for the motions of an aircraft were produced and, therefore, it has no quantitative basis for designing his flying machines. But he had things right at the level he worked. Already with his first efforts, he established the principle that was explained thoroughly in a series of papers: the means of producing lift to compensate weight must be distinct from the ones for generating thrust; a revolutionary idea at that time (Grant and Fliegen, 2003). He properly shifted attention to artificial flight from the simple imitation of birds to development of fixed-wing aircraft.

As of 1891, the German Otto Lilienthal performed about 2,000 glider flights (Grant and Fliegen, 2003). Both Lilienthal and Cayley wrote books and articles about light theory, which influenced the work of other pioneers. Santos-Dumont and the Wright brothers count among the readers.

Born in 1812, William Samuel Henson was, like his father, a successful industrialist in the lacemaking business in Somerset, England, In 1840, under the influence of Cayley’s early writings, Henson and an engineer who also worked in the lacemaking industry, John Stringfellow, designed a steam-driven airplane called an aerial steam carriage. Samuel Henson, John Stringfellow, Frederick Marriott, and D.E. Colombine incorporated as the Aerial Transit Company in 1843 in England, with the intention of raising money to construct the flying machine. The company planned “to convey letters, goods and passengers from place to place through the air,” according to the patent issued on March 28, 1843 for its flying vehicle, which was christened Ariel and was also known as Aerial Steam Carriage (Schmitt, 1990).

The patent obtained by Henson was the first one issued for an airplane in history. Henson’s airplane configuration was comprised of a landing gear, tail surfaces, and engines mounted behind the wing; passengers would be transported in an enclosed fuselage. Two counter-rotating six-bladed propellers would drive the airplane. However, the Aerial Carriage was never built and flown. The Aerial Transit Company was financed by D.E. Columbine; John Marriott, a journalist whose value was that he knew a Member of Parliament; and Mr. Roebuck, who was expected to promote a bill in Parliament for a shareholders company to operate an Aerial Steam Carriage. Henson and Stringfellow engaged in model testing in order to make their airplane become true. In 1843, they obtained the help of Joe Chapman, a mathematician, who also had a whirling arm device. Chapman made more than 2,000 recorded aerodynamic experiments J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 3, pp. 355-379, Jul.-Sep., 2012 365