The Airplane - Jay Spenser [47]
Like so many aviation dreamers in the late nineteenth century, John Montgomery corresponded with Octave Chanute, who devoted space to Montgomery’s work in his 1894 book Progress in Flying Machines. Although this coverage is brief and makes no mention of parabolic airfoils, the 1896 glider Chanute built with Augustus Herring’s help likewise featured a parabolic camber. Consequently, when the Wrights adopted the Chanute-Herring glider as their starting point, they also inherited its bird-inspired airfoil as a point of departure.
While a parabolic camber was a step in the right direction, it was not the ultimate solution to the aerodynamic challenges of wings because the Chanute and Montgomery airfoils were based on guesswork. Mimicking the camber of birds’ wings without understanding the underlying aerodynamic principles, they were far from optimal.
A great deal more thinking and learning needed to be done before the airplane would emerge. It called for a degree of scientific rigor never before witnessed in the field of flight.
The Wright 1900 Glider.
Library of Congress
Wilbur and Orville tested their first glider at Kitty Hawk, North Carolina, in 1900. The brothers had intended to fly this machine, but its performance was so poor that they ended up using it primarily as a kite, sometimes loaded with sand or chains for ballast.
They measured its angle in flight and that of its rope in wind speeds ascertained by an anemometer. A grocer’s scale told them how hard this kite pulled on the rope. From these observed and recorded results, they calculated its lift and drag.
The Wrights had sized this machine using Lilienthal’s lift tables as republished by Octave Chanute. Based on that data, they had believed their first manned glider had sufficient wing area. Now direct experimentation told them it was generating only a little over a third of the expected lift. Something was very definitely wrong.
They returned the next year with a glider of almost twice the wing area. Although they logged many flights in this 1901 machine, it too performed poorly. At the end of the flying season, they went back to Dayton thoroughly discouraged, wondering if they should give up their pursuit of flight.
The Wrights had taken up gliding as a hobby to engage their minds and hands. It was initially Wilbur’s interest, but Orville too had succumbed to flight’s siren call. Talking things through in late 1901, they knew they couldn’t let it go. But with Otto Lilienthal’s lift tables now called into question, what were they to do?
There was only one answer: if Lilienthal’s aerodynamic data were wrong, then they must work up accurate lift and drag tables of their own.
The trees in Dayton were golden brown. Fall crispness filled the air. In a room at the back of the Wright Bicycle Company, Wilbur cut out a small rectangle of thin sheet steel with tin snips. On a worktable, he hammered this flat piece into the airfoil curve he desired. He used solder and wax to build up the leading edge to the right thickness where necessary, and more solder to attach mounting prongs.
Wilbur then brought this completed airfoil to the wind tunnel he and Orville had constructed. Mounted waist high on sturdy legs, it was 6 feet (1.8 meters) long and square in cross section, 16 inches (40 cm) wide by high. At one end was a steel shroud with a fan. When turned on, the fan forced air through the tunnel at a constant 25 mph (40 km/h). The air passed through a metal honeycomb to smooth and align its flow before reaching the test chamber.
Wilbur and Orville Wright built a wind tunnel to probe flight’s secrets at their bicycle shop in Dayton.
National Air and Space Museum, Smithsonian Institution
By 1901, there were perhaps ten wind tunnels in the world. None of them was being put to anything like the systematic, scientifically focused use the brothers