There are two types of airplane engine commonly used: the jet engine;
and the reciprocating or conventional engine, which is an internal
combustion engine like the engines of automobiles. There is a separate
article on internal-combus- tion engines, and one also on jet engines.
There are two types of airplane engine commonly used: the jet engine; and the reciprocating or conventional engine, which is an internal combustion engine like the engines of automobiles. There is a separate article on internal-combus- tion engines, and one also on jet engines. An airplane engine differs from an automobile engine in power and in weight. The most powerful automobile engine in 1954 had about 250 horsepower, which is another way of saying that if it operated at full power it could pull 50 tons a distance of one foot in one second.
One very powerful internal-com bustion airplane engine has 3,500 horsepower, and the J-57 jet engine of 1954 developed 10,000 pounds of thrust, which is about 16,000 horsepower. Airplane engines deliver much more power per pound than automobile engines. Most airplane engines are built to deliver one horsepower for each pound they weigh. Automobile engines can supply at the most one-third of one horsepower per pound. Since a Superfortress bomber often weighs fifty times as much as an automobile, its engine must deliver approximately that much more horsepower.
Each 25 pounds of airplane must have one horsepower to keep it in motion. Normally an automobile hardly ever uses more than 25 to 35 percent of its full horsepower. An airplane needs its full horsepower for takeoffs and climbs, and normally cruises at 65 percent of its power capacity. It is easy to see that airplane engines do more work than automobile engines over a longer period of time. The biggest problem in building airplane engines is finding metals that are strong enough to stand the high heat and pressure (especially in the case of the jet engines) and which at the same time are light enough.
Various alloys of aluminum, nickel, chromium, and steel are most commonly used in constructing airplane engines. TYPES OF airplane engine There are two types of internal-combustion airplane engines. One is the inline water- or air-cooled engine which is very much like the engine an automobile employs. (However a liquid that does not freeze as easily as water—somewhat like the antifreeze used in automobiles—is used instead of water to cool the airplane engine.) An in-line engine has cylinders mounted one behind the other in a line. Most in-line airplane engines used today are air-cooled. Liquid-cooled engines have not been widely used in American airplanes.
