Just an Air
An airliner is a large fixed-wing aircraft for transporting passengers and cargo.
Such aircraft are operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an aircraft intended for carrying multiple passengers in commercial service. The world's first all-metal aircraft was the Junkers F.13, also from 1919 with 322 built. The Ford Trimotor was an important early airliner. With two engines mounted on the wings and one in the nose and a slabsided body, it carried eight passengers and was produced from 1925 to 1933. It was used by the predecessor to TWA, as well as other airlines long after production ceased. In 1932 the 14-passenger Douglas DC-2 flew and in 1935 the more powerful, faster, 21–32 passenger Douglas DC-3. DC-3s were produced in quantity for World War II and sold as surplus afterward.The Douglas DC-3 was a particularly important airplane, because it was the first airliner to be profitable without a government subsidy. The first jet airliners came in the immediate post war era. Turbojet engines were trialled on piston engine airframes, such as the Avro Lancastrian and the Vickers VC.1 Viking, the latter becoming the first jet engine passenger aircraft in April 1948. The first purpose built jet airliners were the de Havilland Comet (UK) and the Avro Jetliner (Canada). The former entered production and service while the latter did not. The Comet was unfortunate in that metal fatigue caused by the square shape of the windows in early versions could cause crashes. The United States gained a huge advantage in design and production in the airline industry in the years leading up to the war, but many of the developments would be put off until after the war as the manufacturing efforts were placed on the war effort. The advancements that the Un
ted States would make in this industry were in large due to the cooperation of the airlines discussing what they desired with the airliner manufacturers. Soon after the war though Douglas made a large advancement with the DC-4, although this could not cross the Atlantic at every point, it was able to make a nonstop flight from New York to the United Kingdom. Due to the war going on, the first batch of these planes went to the U.S. Army and Air Forces, and was named the C-54 Skymaster. Some of these that were used in the war would later be converted for the airline industry, along with the passenger and cargo versions that were placed on the market once the war ended. Douglas would later develop a version of this plane that was pressurized and five feet longer; this redesigned plane would become the DC-6. These DC-6s would be grounded for six months to rectify a few safety issues that were causing in-flight fires. Soon after the DC-4, Lockheed developed the distinctive triple-tail Constellation. An aviation breakthrough, it was the first pressurized airliner, allowing it to fly higher, and therefore further and faster than ever before. Its fuselage was some 127 inches wider than the DC-4's. Drafted by the military in World War II, it experienced a similar late entry into the civilian airline industry. Safety concerns grounded it for six months soon after it entered service while problems were investigated and repaired.
Except for a few experimental or military designs, all aircraft built to date have had all of their weight lifted off the ground by airflow across the wings. In terms of aerodynamics, the fuselage has been a mere burden. NASA and Boeing are currently developing a blended wing body design in which the entire airframe, from wingtip to wingtip, contributes lift. This promises a significant gain in fuel efficiency.