The Belle Isle gas turbine was installed in 1949 and was the first gas turbine built in the United States for the purpose of generating electric power. Its low cost and consistency aroused considerable interest in the electric utility industry, both here and abroad. This led ultimately to the wide-scale adoption of the gas turbine by electric utilities. The Landmark gas turbine was delivered in April 1949 to the Belle Isle Station* of the Oklahoma Gas and Electric Company in Oklahoma City. The Belle Isle turbine, together with a second, identical unit installed in 1952, served the Oklahoma Gas and Electric Company for 31 years. It was eventually withdrawn from service in August 1980 with the closing of the Belle Isle Station.

Gas turbines are internal combustion engines, just like the automobile engine, except that rotating compressors and expansion turbines† are used instead of a piston reciprocating in a cylinder. In an internal combustion engine air is drawn into the machine and compressed, fuel is added to the compressed air, and the resulting mixture is burned, thereby raising the temperature of the gas; the hot gases are then expanded, i.e., their temperature and pressure are lowered by withdrawing the energy supplied by the burning fuel. This extracted energy is used in the compression process and to provide energy to propel an aeroplane, a locomotive, generate electricity or any other uses. In the reciprocating internal combustion engine, such as that used to drive a car, the various processes take place in a cylinder with a reciprocating piston. This engine operates in a non-flow mode, in the sense that all the processes occur in one component. The same processes can be arranged to be carried out in separate components; namely, a compressor, a combustion chamber, and an expansion machine. If a rotary compressor and a rotary expansion engine, that is, an expansion turbine, are used, then the device is known as a gas turbine