Pratt & Whitney

By Judy Rumerman, U.S. Centennial of Flight Commission

Frederick Rentschler knew that the best airplane could only be built around the best engine. "The power plant is at the heart of the matter," he said when he established the Pratt & Whitney Aircraft Company in July 1925 to design and build aircraft engines. The Pratt and Whitney Tool Company, in Hartford, Connecticut provided startup money, factory space, and even a name for the new company.

Renstschler was well qualified for the job. He was a founder of Wright Aeronautical, where he had been involved in producing Hispano-Suiza engines and had been company president. He left Wright when he felt he was not getting enough support for research into new types of engines.

Just six months after forming, the new company produced the successful Wasp engine, which included a number of important technical advances. Soon after it passed the Navy's qualification test in March 1926, the Navy ordered 200 engines. The Wasp exhibited speed, performance, climb, and reliability that contributed to America's leadership in world aviation. The Wasp and its successor, the R-1690 Hornet, practically monopolized Navy aircraft for many years.

The Wasp also dominated the civil market. Airplane builders of the 1930s designed their new transports around the Wasp. These engines powered some 100 different airplanes, including some of the fastest and most famous aircraft of the time—Jimmy Doolittle's Gee Bee and Amelia Earhart's Lockheed Electra 10A, for example.

The company continued to grow, and by 1930, Pratt & Whitney dominated 60 percent of the aero-engine market. Of the 25 engine makers, Wright Aeronautical was the only major competitor.

A second, more powerful engine, the Hornet, followed the Wasp. The Hornet powered larger civil aircraft as well as several military aircraft. A small radial, the Wasp Jr., designed for light transports, trainers, sports aircraft and helicopters, followed the Hornet.

By the early 1930s, Pratt & Whitney was building the Twin Wasp. This engine powered many fighters, bombers, and transports of the period. In 1938 and 1939, France ordered some $85 million worth of the engine. During the war, 173,618 Twin Wasp engines were produced, more than any other engine type in history.

As the war progressed, technology advanced and more powerful engines became common. Pratt & Whitney produced both the Twin Wasp and the Double Wasp R-2800, which powered much of the U.S. fighter fleet as well as many British planes. Moreover, Pratt & Whitney engines powered 98 percent of all transports used by the military. Altogether Pratt & Whitney and its licensees, among them the automobile companies, shipped 363,600 engines for use during the war, and employees worked long hours with no vacations for several years.

As the airliner industry resumed after the war, Pratt & Whitney engines were picked to power most of the two- and four-engine aircraft. The Double Wasp powered the successful DC-6, and more than 125,000 of these engines were eventually produced. The Wasp Major was Pratt & Whitney's last and largest piston engine. This engine powered the Boeing B-50, the first airplane to fly nonstop around the globe.

Pratt & Whitney had spent the war years focusing exclusively on its piston engines, and in 1945, was far behind its competitors in jet engine development. General Electric and also Westinghouse were already building turbojets. Pratt & Whitney began by first building jets of British design. But it realized that it would have to begin building its own jet engines. The company's first jet engine, the J42 Turbo-Wasp, was delivered to the Navy in November 1948 for installation in the Grumman F9F-2 Panther. A second jet engine, the J48, began production in 1950. Both these engines powered aircraft that served in the Korean War.

On April 15, 1952, a prototype Boeing B-52 Air Force bomber debuted with eight Pratt & Whitney J57 turbojets. That year, the company won the prestigious Collier Trophy for "the greatest achievement in aviation in America." Both the Air Force and Navy used the J57 to power their fighter squadrons. In May 1953, the J57-powered Air Force F-100 Sabre became the first aircraft to break the speed of sound in horizontal flight. The commercial version of the J57—the JT3 engine—powered Boeing's first jet transport, the 707, and the Douglas DC-8.

Flying Colors N409BN - a Braniff Boeing 727-214 with Pratt & Whitney JT8D-9A engines seen in Kansas in May 1979. Image courtesy of AirNikon. Find more of his photos at Airliners.net

The J58, developed in the late 1950s, was selected for the SR-71 Blackbird reconnaissance aircraft. The first engine designed to be flight-qualified at Mach 3 for the Air Force, it required new materials and fuel that could withstand the temperatures and stresses it would encounter. In July 1976, J58 engines powered an SR-71 to a world altitude record of 84,069 feet (25,624 kilometers) and a second Blackbird to a world speed record of 2,193 miles per hour (3,529 kilometers per hour).

With the frontiers of space opening, Pratt & Whitney engineers used cryogenic hydrogen as a liquid fuel for rocket propulsion. A Pratt & Whitney hydrogen engine designed in 1958 powered the Centaur upper stage that rode atop the Atlas space launch vehicle. In 1963, the RL10 became the first liquid hydrogen-fueled engine to operate successfully in space. In 2000, the RL10 was still being used to launch satellites into space.

Also in 1963, Pratt & Whitney started using the JT8D jet engine for short-to-medium-range commercial aircraft. The engine has been used on the Boeing 727, Douglas DC-9, and Boeing 737. Since starting commercial service, more than 14,000 JT8Ds have been produced, totaling more than one-half billion hours of service with more than 350 operators. In response to environmental concerns that began in the 1970s, the company began developing a new version of the engine, the JT8D-200 series, designed to be quieter, cleaner, more efficient, and yet more powerful than earlier models.

The all-new JT9D engine of the mid-1960s introduced technological advances in mechanics, aerodynamics, and materials. Designed for wide-body aircraft, the engine entered commercial service in January 1970 on a Pan American Boeing 747 flight from New York to London.

Pratt & Whitney's first F100 military engine flew on July 27, 1972, on a twin-engine F-15 Eagle. It also powered the F-16 Fighting Falcon. This was followed in the next decades by the F100-PW-220 and -229 for the F-15 Eagle and F-16, the F117-PW-100 for the C-17 Globemaster III, and the F119-PW-100, for the F-22 Raptor.

The PW2000 engine was certified in 1983 for the Boeing 757. Designed for short-to-medium flights, it was the first engine to use digital controls for maximum fuel efficiency.

In 1982, Pratt & Whitney began developing the PW4000 series turbofan engine family, designed for wide-body aircraft. The first entered service in 1987 with Pan American and with Singapore Airlines and is used on Airbus Industrie A300 and A310 aircraft; Boeing 747 and 767 aircraft; and the Boeing MD-11.

During the 1980s, Pratt & Whitney participated in the V2500 engine project, targeted for Airbus A319/320/321 aircraft, and the Boeing MD-90 series. Development began in late 1983 as part of a five-nation consortium. The engine entered service in 1989.

In the early 1990s, Pratt & Whitney started developing engines designed specifically for the Airbus new A330 twinjet. A new PW4000 engine entered service in December 1994, already approved for 90-minute extended-range twin-engine operations (ETOPS), an industry first. In June 1995, a second larger PW4000 engine launched 777 commercial service on a transatlantic flight from London to Washington. For new 777s requiring increased thrust, Pratt & Whitney developed the PW4090 that entered service in March 1997. A second and more powerful model, the PW4098 engine, entered service on the stretched 777-300 model in 1999.

In 1995, Pratt & Whitney Space Propulsion began supplying turbopumps for the Space Shuttle. The first new advanced hydrogen turbopump was used on the Shuttle in 1999. A new rocket engine, the RD-180, produced by Russia's NPO Energomash and Pratt & Whitney, made its service debut in 1999 on an Atlas IIIA rocket.

The Pratt & Whitney PW6000 launched in 1998. This engine will initially power the new Airbus A318, a 100-passenger aircraft and is envisioned as a replacement for the workhorse JT8D.

In the new century, Pratt & Whitney continues to work on new propulsion systems that may propel missiles several times the speed of sound. It is also working to provide power for tomorrow's military aircraft.
 

Note: This article was commissioned by and first appeared on NASA's U.S. Centennial of Flight web site. It appears here with permission. We gratefully acknowledge both the author and NASA.

Additional References:
Gunston, Bill. The Development of Piston Aero Engines. Somerset, England: Haynes Publishing, 1993.
Heron, S.D. History of the Aircraft Piston Engine: A Brief Outline. New York: Ethyl Corporation, 1961.