Ludwig Boltzmann e a arte de voar

Uma das facetas pouco conhecidas de Ludwig Boltzmann diz respeito a sua fascinação pela aviação. Em 1894, em uma palestra de muita repercussão, na qual fez voar pelo auditório uma réplica de uma aeronave, Boltzmann defendeu veementemente investimentos na área. Discuto neste artigo o envolvimento de Boltzmann, a repercussão de sua palestra e sua correspondência com dois pioneiros da aviação, Otto Lilienthal e Wilhelm Kress.

Calculating Coefficients

Wilbur and Orville Wright, both engineer brothers, studied results of Germany’s Otto Lilienthal to improve their airplane flight experiments and calculations. The Wright gliders of 1900 and 1901 used wings like Lilienthal’s, and the brothers relied on his calculations for determining coefficient of lift. When the Wrights compared their results with those of Lilienthal, they found only small disagreements. With the coefficients of lift and drag holding up to their scrutiny, the Wrights turned their attention to the only other possible source of error in the equations, the Smeaton coefficient of air pressure. The Wrights built lift balance after discovering a discrepancy between actual and predicted values for lift and drag. The brothers plotted out the relationship among lift, thrust, weight, and drag. The Wrights figured out that the margins are a tribute to their genius. Perhaps all they proved in 1903 was that flight was possible on a cold and windy day in North Carolina.

First Flights

This article discusses work of engineers apart from Wright Brothers in the field of aviation. Octave Chanute, an American who made his fortune as a railroad and bridge engineer, began to try his hand at flight in 1875. A German engineer, Otto Lilienthal, who was achieving international fame with spectacular flights in hang gliders of his own design, inspired William Randolph Hearst. Lilienthal made steady progress until 1896, when his glider stalled, and he fell to the ground and died from internal injuries. Samuel Pierpont Langley, a professor of physics, after securing research funds, began to measure how much power was required to lift a weight with a wing moving through the air. He used a technique for testing air foils that had been described 50 years earlier by Sir George Cayley. Langley estimated that human flight would require an engine of at least 12 hp. In 1899, his friend Robert Thurston, a Cornell engineering professor, introduced him to Charles Manly, who had graduated from Cornell as a mechanical engineer.