The Airplane - Jay Spenser [72]
On July 18, 1905, at Billancourt, France, in Paris’ western suburbs, a glider on pontoons bobbed in the Seine River. Designed by Gabriel Voisin with ideas contributed by Louis Blériot, who had commissioned Voisin to build it, this craft was a Hargrave box kite with short biplane wings of unequal span.
Between the wings on each side were two vertical fore-and-aft fabric panels. The outboard “side curtains” were canted to connect the tips of the shorter-span lower wing to those of the longer-span upper one. At the rear, a biplane tail unit was likewise enclosed top, bottom, and sides like a Hargrave kite. Voisin counted on these design features to lend his glider inherent lateral, longitudinal, and directional stability.
The Voisin-Blériot glider also showed the influence of the Wright brothers, whose galvanizing success with the 1902 Glider had reawakened Europe’s determination to be first in flight. Most noticeable was this glider’s front elevator, which all European biplanes would sport for some years because of the Wrights.
Gabriel Voisin climbed into the glider’s seat. At his signal to the crew of an idling motorboat, its engine roared and a tow rope came taut. The glider accelerated smoothly across the water, lifted free, and immediately dipped a wing. Falling into an uncommanded sideslip, it broke up on impact.
Voisin came close to drowning. The reason was one-axis control: aside from its front elevator, the Voisin-Blériot float glider of 1905 incorporated no mechanism for guiding its course through the air.
Between late June and mid-October 1905, the Wright brothers logged more than forty flights at Huffman Prairie in a new airplane fitted with the previous one’s engine. The Flyer III, also called the Wright 1905 Flyer, differed noticeably from its predecessors by having its front elevator farther forward and its rear rudder farther aft.
Flown at Huffman Prairie in 1905, the Wright Flyer III was history’s first practical airplane. Its longest flight came on October 5, when Wilbur covered nearly 25 miles (40 km) in thirty-eight minutes aloft.
Library of Congress
This fore-and-aft lengthening was made after Orville lost control of the craft on July 14. The machine crashed nose first, its elevator and supporting outriggers absorbing some of the impact. Bouncing down the field, it slid upended to a jarring stop that shot Orville through the shattered top wing. He was battered and dazed but, fortunately, unhurt.
The brothers rebuilt the craft with an enlarged elevator set farther forward. This change significantly improved the flyer’s longitudinal stability and handling. Eliminating the problem of occasional losses of control, it also cleared the way for remarkable successes as the flying season wore on.
One problem still remained, however. The Flyer III continued to exhibit an alarming tendency for the wings on the low side to continue to drop during banks. On one September flight, the machine had turned uncommanded into the tree it was circling. Torn branches adorned its struts when it landed.
What was happening? The low wings, being on the inside of a turn, were slowing down and generating reduced lift. When the pilot applied opposite warping to bring up these low wings, the combination of a high angle of attack and too little forward airspeed caused them to stall out, precipitating a further drop.
Given sufficient altitude, control was regained by putting the nose down for more flying speed and then bringing the wings level with wing warping, which remained effective throughout on the high side. However, the Wrights lacked sufficient altitude for this to be an option because they were staying low for safety.
The solution turned out to be to unlink the rudder from the wing warping, thus allowing its independent use. In banks when the low wing would not come up, the application of “opposite rudder” or “top rudder