Steady accumulation of improvements, fostered by the likes of American businessman Donald Douglas, who founded his own aircraft company in California in 1920. By 1933 he had introduced an airplane of truly revolutionary appeal, the DC-1 (for Douglas Commercial). Its 12-passenger cabin included heaters and soundproofing, and the all-metal airframe was among the strongest ever built.
By 1936 Douglas's engineers had produced one of the star performers in the whole history of aviation, the DC-3. This shiny, elegant workhorse incorporated just about every aviation-related engineering advance of the day, including almost completely enclosed engines to reduce drag, new types of wing flaps for better control, and variable-pitch propellers, whose angle could be altered in flight to improve efficiency and thrust. The DC-3 was roomy enough for 21 passengers and could also be configured with sleeping berths for long-distance flights. Passengers came flocking. By 1938, fully 80 percent of U.S. passengers were flying in DC-3s and a dozen foreign airlines had adopted the planes. DC-3s are still in the air today, serving in a variety of capacities, including cargo and medical relief, especially in developing countries. By 1936 Douglas's engineers had produced one of the star performers in the whole history of aviation, the DC-3. This shiny, elegant workhorse incorporated just about every aviation-related engineering advance of the day, including almost completely enclosed engines to reduce drag, new types of wing flaps for better control, and variable-pitch propellers, whose angle could be altered in flight to improve efficiency and thrust. The DC-3 was roomy enough for 21 passengers and could also be configured with sleeping berths for long-distance flights. Passengers came flocking. By 1938, fully 80 percent of U.S. passengers were flying in DC-3s and a dozen foreign airlines had adopted the planes. DC-3s are still in the air today, serving in a variety of capacities, including cargo and medical relief, especially in developing countries. Aviation's next great leap forward, however, was all about power and speed. In 1929 a 21-year-old British engineer named Frank Whittle had drawn up plans for an engine based on jet propulsion, a concept introduced near the beginning of the century by a Frenchman named Rene Lorin. German engineer Hans von Ohain followed with his own design, which was the first to prove practical for flight. In August 1939 he watched as the first aircraft equipped with jet engines, the Heinkel HE 178, took off.
In 1942 Adolf Galland—director general of fighters for the Luftwaffe, veteran of the Battle of Britain, and one of Germany's top aces—flew a prototype of one of the world's first jets, the Messerschmitt ME 262. "For the first time, I was flying by jet propulsion and there was no torque, no thrashing sound of the propeller, and my jet shot through the air," he commented. "It was as though angels were pushing." As Adolf Galland and others soon realized, the angels were pushing with extraordinary speed. The ME 262 that Galland flew raced through the air at 540 miles per hour, some 200 mph faster than its nearest rivals equipped with piston-driven engines. It was the first operational jet to see combat, but came too late to affect the outcome of the war. Shortly after the war, Captain Chuck Yeager of the U.S. Air Force set the bar even higher, pushing an experimental rocket-powered plane, the X-1, past what had once seemed an unbreachable barrier: the speed of sound. This speed varies with air temperature and density but is typically upward of 650 mph. Today's high performance fighter jets can routinely fly at two to three times that rate. In 1942 Adolf Galland—director general of fighters for the Luftwaffe, veteran of the Battle of Britain, and one of Germany's top aces—flew a prototype of one of the world's first jets, the Messerschmitt ME 262. "For the first time, I was flying by jet propulsion and there was no torque, no thrashing sound of the propeller, and my jet shot through the air," he commented. "It was as though angels were pushing." As Adolf Galland and others soon realized, the angels were pushing with extraordinary speed. The ME 262 that Galland flew raced through the air at 540 miles per hour, some 200 mph faster than its nearest rivals equipped with piston-driven engines. It was the first operational jet to see combat, but came too late to affect the outcome of the war. Shortly after the war, Captain Chuck Yeager of the U.S. Air Force set the bar even higher, pushing an experimental rocket-powered plane, the X-1, past what had once seemed an unbreachable barrier: the speed of sound. This speed varies with air temperature and density but is typically upward of 650 mph. Today's high performance fighter jets can routinely fly at two to three times that rate.
The jet engine had a profound impact on commercial aviation. As late as the 1950s transatlantic flights in propeller-driven planes were still an arduous affair lasting more than 15 hours. But in the 1960s aircraft such as Boeing's classic 707, equipped with four jet engines, cut that time in half. The U.S. airline industry briefly flirted with a plane that could fly faster than sound, and the French and British achieved limited commercial success with their own supersonic bird, the Concorde, which made the run from New York to Paris in a scant three and a half hours. Increases in speed certainly pushed commercial aviation along, but the business of flying was also demanding bigger and bigger airplanes. Introduced in 1969, the world's first jumbo jet, the Boeing 747, still holds the record of carrying 547 passengers and crew. The jet engine had a profound impact on commercial aviation. As late as the 1950s transatlantic flights in propeller-driven planes were still an arduous affair lasting more than 15 hours. But in the 1960s aircraft such as Boeing's classic 707, equipped with four jet engines, cut that time in half. The U.S. airline industry briefly flirted with a plane that could fly faster than sound, and the French and British achieved limited commercial success with their own supersonic bird, the Concorde, which made the run from New York to Paris in a scant three and a half hours. Increases in speed certainly pushed commercial aviation along, but the business of flying was also demanding bigger and bigger airplanes. Introduced in 1969, the world's first jumbo jet, the Boeing 747, still holds the record of carrying 547 passengers and crew.
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