The Airplane - Jay Spenser [59]
The revolutionary Boeing B-47 Stratojet took flight on the forty-fourth anniversary of the Wright brothers’ success at Kitty Hawk.
Boeing
In addition to allowing jetliners to fly faster and use less fuel, wing sweep imparts greater overall stability. However, swept-wing aircraft are subject to a constant mild corkscrewing motion called Dutch roll. Named for the natural back-and-forth body swings that a Dutch skater might describe when crossing the ice, this coupled rolling oscillation is benign but can make passengers queasy. Consequently, all jetliners have yaw dampers that automatically negate this Dutch roll for a more comfortable ride.3
When flying commercially, you may notice that your jet’s wings flex a bit during flight. This is entirely normal. Indeed, few transport planes have ever been designed with totally rigid wings. This flexing occurs only up and down because jetliner wings are entirely rigid torsionally. Of course, they are all enormously strong because government design certification requirements specify that they must be able to withstand loads half again greater than any they might ever conceivably encounter during a lifetime of operation. In fact, our mechanical wings whisk enormous loads at astonishing speeds and altitudes with by far the greatest safety ever achieved by any mode of mass transportation.
7 EMPENNAGE
WHALE FLUKES AND ARROW FEATHERS
Give me a place to stand and a lever long enough, and I will move the world.
—ARCHIMEDES (287–212 BCE)
Wellwood Beall had a dream. He was going to make history with a flying boat of unprecedented size, performance, and luxury. It would be the biggest and best yet of the ocean-spanning, boat-hulled airliners flown by Pan American Airways.
Beall, an aeronautical engineer from Colorado, worked for Boeing in Seattle. Although just twenty-nine years old in 1936, he was one of its ablest salesmen. It bothered him that his company, citing existing commitments and insufficient funds, had declined Pan Am’s invitation to develop a new airliner. Working at home on his dining room table, he sketched out a huge new flying boat with lines like a whale. As he conceived it, this long-range airliner would have two decks, the upper for crew and baggage and the lower—configured as the aerial equivalent of an ocean liner—for passengers.
Beall’s vision was persuasive and his colleagues changed their minds. Boeing would build Pan Am’s new flying boat after all.
The prototype Boeing 314 Clipper rocked gently in the swells of Elliott Bay. Evening sunlight raked the Seattle skyline. A bracing west wind had died down.
It was June 7, 1938. Taxi tests completed, it was time to take the new airplane aloft for the first time. Wellwood Beall stood on the mooring barge and helped Boeing chief test pilot Eddie Allen and his crew hop across to the bobbing Clipper. Workers untied mooring ropes and the airplane drifted away, its engines coming to life one after the other.
Aboard the Clipper, Allen led his crew through preflight checks and engine run-ups. All was ready, and Allen—an aeronautical engineer with a master’s touch on the controls—opened the throttles wide. Four radial engines bellowed as Boeing’s Clipper accelerated, its planing hull lifting to skim the water’s surface. Allen pulled back on the control wheel and the ship rose into the air.
Unbidden, the 314 dipped to the right. Allen tried to counteract the bank with his controls, but it was as if somebody else were flying the machine. He also found it directionally unstable, its nose unable to hold a steady course.
The wide right-hand arc brought them inland. Using the throttles, Allen lifted the low wing. Differential engine power provided enough control to set down after thirty-eight minutes aloft on Lake Washington, which offered calmer waters on the other side of Seattle. The crew heaved a collective sigh of relief as the machine decelerated, its hull settling into the water.
Eddie Allen knew what the problem was. The prototype 314’s single vertical stabilizer