Founded in 1927 as Prudden-San Diego Airplane Company, the firm built only three all-metal airplanes before the Great Depression hit in 1929. The company then began making components for other manufacturers.

Renamed Solar Aircraft Company in 1929 (reputedly because of San Diego's sunny climate), the young company struggled through the 1930s making a variety of products. It was then that Solar began pioneering with then-difficult techniques to fabricate high-temperature materials, such as stainless-steel for airplane engine exhaust manifolds.

Solar Aircraft was a vital defense company during World War II working around the clock to make more than 300,000 exhaust manifolds for U.S. airplanes. During the war, Solar was selected to help pioneer development of some of the critical high-temperature components for America's first aircraft gas turbines (jet engines). It was then that Solar began taking its first steps in a decades-long journey to become the world leader in industrial gas turbines and turbomachinery packages.

When peace was re-established in 1945, Solar Aircraft Company soon found itself again struggling, this time to survive the loss of its wartime production work. Its peoples' skills in metallurgy and fabricating difficult materials helped Solar land new contracts to produce aircraft/aerospace hardware ,such as jet engine afterburners and rocket components. Meanwhile, the workers also made stainless-steel caskets, frying pans, bulk milk containers and redwood furniture to help the company remain viable.

Late in the 1940s, Solar won a U.S. Navy contract to develop and manufacture small, 35-kW (45-hp) gas turbines to power portable pump units for fighting fires aboard ships. The company subsequently was awarded another Navy contract to build 300-kW (400-hp) gas turbine units to generate shipboard electrical power.

A fateful event occurred late in the 1950s when Solar earned yet another U.S. Navy contract - this one calling for development of a 750-kW(1000-hp) engine for high-speed boat propulsion. The result was the Saturn® gas turbine, which entered production in 1960. (That same year Solar Aircraft Company became a subsidiary of International Harvester Company and, three years later, became an IH division).

Solar's leaders realized that the Saturn turbine also had definite commercial potential because it was far smaller, lighter in weight, more reliable, and easier to maintain than the large, low-speed reciprocating engines that had been traditional for industrial applications. The Saturn engine went on to become the world's most widely used industrial gas turbine with some 4800 units in 80 countries. It remains in production today in two uprated and enhanced configurations.

Solar recognized that to win over customers from reciprocating equipment, the company would have to offer fully factory-assembled-and-tested turbomachinery packages, such as complete gas compressor sets, pump-drive packages and generator sets, rather than bare gas turbine engines. Solar began in 1960 to build its own line of centrifugal-flow natural-gas compressors, which now encompasses 18 models.

As Saturn turbine packages gained wider industrial acceptance, it became apparent that business opportunities existed for a more powerful gas turbine.

Work began in the mid-1960s on the Centaur®gas turbine, which entered service in 1968 at 2015 kW (2700 hp). Today's Centaur 40 gas turbine delivers 3520 kW (4700 hp).

After 46 years, Solar left the aircraft/aerospace industry in 1973 to concentrate its resources on industrial gas turbines, turbomachinery systems and support services. During its last decade of involvement with the aerospace/aircraft industry, Solar's work included production of mission-critical fuel lines, communications antennae, and nuclear generator thermal radiators for the Saturn/Apollo lunar landings, hot-section components for airline jet engines, and aerodynamic control devices for the famed F-4 Phantom jet fighter plane. Solar in 1977 introduced its then largest and most powerful engine, the 7900 kW (10,600-hp) Mars® gas turbine. Today Solar offers Mars engines in two output ranges, the 9860 kW (13,220-hp) Mars 90 and 11 190 (15,000-hp) Mars 100 gas turbines.

Caterpillar Tractor Co. (now Caterpillar Inc.) purchased the assets of Solar Turbines from International Harvester Company on May 31, 1981. Solar Turbines Incorporated is a wholly owned subsidiary of Caterpillar Inc., which is headquartered in Peoria, Illinois.

In 1985, Solar introduced a more powerful member of the Centaur engine family - the Centaur 50 now rated at 4570 kW (6130 hp). With some 3000 units in service, Centaur turbines rank second only to our Saturn turbines in total units installed worldwide. Our first Taurus™ 60 gas turbine left Solar's factory in 1990; its rating is 5740 kW (7700hp).

SoLoNOx Technology: By 1992, Solar had been developing combustion technology for nearly 20 years to reduce exhaust emissions when it introduced pollution-prevention SoLoNOx gas turbines. SoLoNOx engine technology is available for the CentaurMercuryTaurusMars and Titan™ gas turbines. Our advanced, dry, lean-premixed SoLoNOx combustion technology also can be retrofitted to many previously installed models of those turbines to allow owners to comply with newer, more stringent emissions regulations. Here again, Solar leads the industry with more than 2000 SoLoNOx engines shipped to customers in numerous countries.

The Taurus 70 gas turbine, introduced in 1993, is now rated at 7520 kW (10,310 hp). It was the first engine introduced into the gas turbine industry with pollution-prevention, lean-premixed combustion technology as a standard feature.

In more recent events, Solar Turbines announced in 1997 that it was developing the new simple-cycle Titan 130 gas turbine for industrial applications. The Titan 130 engine is available in a two-shaft, variable-speed version for mechanical-drive applications and in a single-shaft, constant-speed configuration for powering continuous-duty generator sets rated at 15 000 kWe. The Titan 130 gas turbine is designed to provide a simple-cycle thermal efficiency of greater than 34.5 percent.

Solar also began the field testing phase in 1997 of the world's first industrial gas turbine equipped with ceramic components in place of standard metal components, which require advanced cooling technologies to maintain metal temperatures at acceptable levels. Developed under a U.S. Department of Energy (DOE) program, the ceramic stationary gas turbine (CSGT) test engine is a single-shaft Centaur 50S industrial gas turbine installed at an oil company's cogeneration/steam-flooding site in California's San Joaquin Valley. The successful application of ceramic components would deliver several major benefits, including increased power by allowing operation at higher turbine inlet temperatures, higher thermal efficiency by reducing the need to use compressed air from the engine's compressor for component cooling, and lower exhaust emissions.

In a related program, Solar, in 1997, unveiled details of its 4.2-MWe optimized, recuperated-cycle Mercury™ 50 gas turbine generator system being developed in a cooperative effort with the U.S. DOE for the Advanced Turbine Systems program. The goals for the ATS industrial turbine program called for units that would be much more energy efficient and emit far fewer exhaust pollutants than 1991-era industrial gas turbines while also cutting the cost of producing electrical power by 10 percent.

Solar Turbines ranks as a world leader in industrial turbines up to 25,000 hp. The company has sold more than 15,000 gas turbine systems which are operating on land and offshore to provide rugged, reliable power for base-load electricity, cogeneration and standby power; producing, processing and transporting natural gas and oil; and marine propulsion.