2 minute read

Jet Engine

Turboprop Engines

When jet engines were first introduced in the 1940s, they were not very efficient. In fact, the cost of operating a jet airplane was so great that only military uses could be justified. At the time, commercial airline companies decided to compromise between the well-tested piston engines they were then using and the more powerful, but more expensive, jet engines. The result was the turboprop engine. In a turboprop engine, a conventional propeller is attached to the turbine in a turbojet engine. As the turbine is turned by the series of reactions described above, it turns the airplane's propeller. Much greater propeller speeds can be attained by this combination that are possible with simple piston-driven propeller planes. The problem is that at high rotational speeds, propellers begin to develop such serious eddying problems that they actually begin to slow the plane down. Thus, the maximum efficient speed at which turboprop airplanes can operate is less than 450 MPH (724 km/h).

Resources

Books

Boyne, Walter, Terry Gwynn-Jones, and Valerie Moolman. How Things Work: Flight. Alexandria, VA: Time-Life Books, 1990.

Cumpsty, Nicholas A. Jet Propulsion: A Simple Guide to the Aerodynamic and Thermodynamic Design and Performance of Jet Engines. Cambridge: Cambridge University Press, 1998.

Gunston, Bill. The Development of Jet and Turbine Aero Engines. 2nd ed. New York: Haynes Publishing, 1998.

"Jet Engine." In The Rand McNally Encyclopedia of Transportation. Chicago: Rand McNally, 1976.

"Jet Engines." In How It Works. New York: Simon and Schuster, 1971.

Karagozian, A. R. "Jet Propulsion." In Encyclopedia of Physical Science and Technology, edited by Robert A. Meyers. Orlando Academic Press, 1987.

Shaw, John M. "Jet Engines." In Magill's Survey of Science: Applied Science Series, edited by Frank N. McGill. Pasadena, CA: Salem Press, 1993.


David E. Newton

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Afterburner

—A device added at the rear of a jet engine that adds additional fuel to the exhaust gases, increasing the efficiency of the engine's combustion.

Ramjet

—A simple type of air-breathing jet engine in which incoming air is compressed and used to burn a jet fuel such as kerosene.

Turbofan engine

—A type of air-breathing jet that contains a large fan at the front of the engine operated by the turbine at the rear of the engine.

Turbojet

—A type of air-breathing jet engine in which some of the exhaust gases produced in the engine are used to operate a compressor by which incoming air is reduced in volume and increased in pressure.

Turboprop

—An engine in which an air-breathing jet engine is used to power a conventional propeller-driven aircraft.

Additional topics

Science EncyclopediaScience & Philosophy: Intuitionist logic to KabbalahJet Engine - Scientific Principle, Rockets, Ramjets, Turbojets, Turbofan Jets, Afterburners, Turboprop Engines