Commercial Aviation

Commercial Aviation

Commercial aviation began in January of 1914, just 10 years after the Wrights pioneered the skies. The first regularly scheduled passenger line in the world operated between Saint Petersburg and Tampa, Florida. Commercial aviation developed slowly during the next 30 years. Airplane technology was driven by the two world wars and service demands of the U.S. Post Office. It was not until after World War II (1939-1945), when comfortable, pressurized air transports became available in large numbers, that the airline industry really prospered.

In the early 1920s the air-cooled engine was perfected, along with its streamlined cowling, or engine casing. Light and powerful, these engines gave strong competition to the older, liquid-cooled engines. In the mid-1920s light airplanes were produced in great numbers, and club and private pleasure flying became popular. The inexpensive DeHavilland Moth biplane, introduced in 1925, put flying within the financial reach of many enthusiasts. The Moth could travel at 145 km/h (90 mph) and was light, strong, and easy to handle.

Manufacturing of Commercial Airplanes

Instrument flying became practical in 1929, when the American inventor Elmer Sperry perfected the artificial horizon and directional gyro. On September 24, 1929, James Dolittle, an American pilot and army officer, proved the value of Sperry's instruments by taking off, flying over a predetermined course, and landing, all without visual reference to the earth.

Introduced in 1933, Boeing's Model 247 was considered the first truly modern airliner. It was an all-metal, low-wing monoplane, with retractable landing gear, an insulated cabin, and room for 10 passengers. An order from United Air Lines for 60 planes of this type tied up Boeing's production line and led indirectly to the development of perhaps the most successful propeller airliner in history, the Douglas DC-3. Trans World Airlines, not willing to wait for Boeing to finish the order from United, approached airplane manufacturer Donald Douglas in Long Beach, California, for an alternative, which became, in quick succession, the DC-1, the DC-2, and the DC-3.

The DC-3 carried 21 passengers, used powerful, 1000-horsepower engines, and could travel across the country in less than 24 hours of travel time, though it would have to stop many times for fuel. The DC-3 quickly came to dominate commercial aviation in the late 1930s, and some DC-3s are still in service today.

Boeing provided the next major breakthrough with its Model 307 Stratoliner, a pressurized derivative of the famous B-17 bomber, entering service in 1940. With its regulated cabin air pressure, the Stratoliner could carry 33 passengers at altitudes up to 6100 m (20,000 ft) and at speeds of 322 km/h (200 mph).

When the United States entered World War II in 1941, there were fewer than 300 planes in airline service. Airplane production concentrated mainly on fighters and bombers, and reached a rate of nearly 50,000 a year by the end of the war. A large number of sophisticated new transports, used in wartime for troop and cargo carriage, became available to commercial operators after the war ended. Pressurized propeller planes such as the Douglas DC-6 and Lockheed Constellation, early versions of which carried troops and VIPs during the war, now carried paying passengers on transcontinental and transatlantic flights.

Wartime technology efforts also brought to aviation such critical new developments as the jet engine, which truly revolutionized commercial air transportation in the late 1950s. Jet transportation in the commercial-aviation arena arrived in 1952 with Britain's DeHavilland Comet, an 885-km/h (550-mph), four-engine jet. The Comet quickly suffered two fatal crashes due to structural problems and was grounded. This complication gave American manufacturers Boeing and Douglas time to bring the 707 and DC-8 to the market. Pan American World Airways inaugurated Boeing 707 jet service in October of 1958, and air travel changed dramatically almost overnight. Transatlantic jet service enabled travelers to fly from New York City to London, England, in less than eight hours, half the propeller-airplane time. Boeing's new 707 carried 112 passengers at high speed and quickly brought an end to the propeller era for large commercial airplanes.

After the big, four-engine 707s and DC-8s had established themselves, airlines clamored for smaller, shorter-range jets, and Boeing and Douglas delivered. Douglas delivered the DC-9, and Boeing produced both the 737 and the trijet 727. The next frontier, pioneered in the late 1960s, was the age of the jumbo jet. Boeing, McDonnell Douglas, and Lockheed all produced wide-body airliners, sometimes called jumbo jets. Boeing developed and still builds the 747. McDonnell Douglas built a somewhat smaller, three-engine jet called the DC-10, now being produced in an updated version known as the MD-11. Lockheed built the L-1011 Tristar, a trijet that competed with the DC-10. The L-1011 is no longer in production, and Lockheed-Martin does not build commercial airliners anymore.

In the 1980s McDonnell Douglas introduced the twin-engine MD-80 family, and Boeing brought on-line the narrow-body 757 and wide-body 767 twin jets. Airbus Industrie had developed the A300 wide-body twin during the 1970s. During the 1980s and 1990s Airbus expanded its family of aircraft by introducing the slightly smaller A310 twin jet, and the narrow-body A320 twin, a unique, so-called fly-by-wire aircraft with sidestick controllers for the pilots rather than conventional control columns and wheels. Airbus also introduced the larger A330 twin and the A340, a four-engine airplane for longer routes, where passenger loads are somewhat lighter. In 1995 Boeing introduced the 777, a wide-body craft that can hold up to 400 passengers.