Most airplane engines are built to deliver one horsepower for each pound they weigh

Most airplane engines are built to deliver one horsepower for each pound they weigh. An airplane engine differs from an automobile engine in power and in weight.. Each 25 pounds of airplane must have one horsepower to keep it in motion.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. One very powerful Car Engine Parts 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. Since a Superfortress bomber often weighs fifty times as much as an automobile, its engine must deliver approximately that much more horse­power.) An in-line engine has cylinders mounted one behind the other in a line. It is easy to see that air­plane engines do more work than auto­mobile engines over a longer period of time. Airplane engines deliver much more power per pound than automobile en­gines. An airplane needs its full horsepower for takeoffs and climbs, and normally cruises at 65 percent of its power capacity. Various alloys of aluminum, nickel, chromium, and steel are most commonly used in constructing airplane engines. There is a separate article on internal-combus- tion engines, and one also on jet engines. Normally an automobile hardly ever uses more than 25 to 35 percent of its full horsepower. TYPES OF airplane engine There are two types of internal-com­bustion airplane engines. (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. Automobile engines can sup­ply at the most one-third of one horse­power per pound. Liquid-cooled engines have not been widely used in American airplanes. One is the in­line water- or air-cooled engine which is very much like the engine an automo­bile employs. 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. Most in-line airplane engines used today are air-cooled. 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.