The Pratt & Whitney JT9D engine was the first high bypass ratio

jet engine A jet engine is a type of reaction engine discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include Rocket engine, rocket, Pump-jet, water jet, and ...

to power a wide-body airliner. Its initial application was the Boeing 747-100, the original "Jumbo Jet". It was

Pratt & Whitney Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of Raytheon Technologies. Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially airlines) and military av ...

's first high-bypass-ratio turbofan.

Development

The JT9D program was launched in September 1965 and the first engine was tested in December 1966. It received its FAA certification in May 1969 and entered service in January 1970 on the Boeing 747. It subsequently powered the

Boeing 767 The Boeing 767 is an American wide-body aircraft developed and manufactured by Boeing Commercial Airplanes. The aircraft was launched as the 7X7 program on July 14, 1978, the prototype first flew on September 26, 1981, and it was certified o ...

, Airbus A300 and Airbus A310, and

McDonnell Douglas DC-10 The McDonnell Douglas DC-10 is an American trijet wide-body aircraft manufactured by McDonnell Douglas. The DC-10 was intended to succeed the DC-8 for long- range flights. It first flew on August 29, 1970; it was introduced on August 5, 19 ...

. The enhanced JT9D-7R4 was introduced in September 1982 and was approved for 180-minute

ETOPS ETOPS () is an acronym for ''Extended-range Twin-engine Operations Performance Standards''—a special part of flight rules for one-engine-inoperative flight conditions. The International Civil Aviation Organization (ICAO) coined the acronym for ...

for twinjets in June 1985. By 2020, the JT9D had flown more than 169 million hours. Production ceased in 1990, to be replaced by the new PW4000. The JT9D was developed from the STF200/JTF14 demonstrator engines. The JTF14 engine had been proposed for the C-5 Galaxy program but the production contract was awarded to the General Electric TF39. The engine's first test run took place in a test rig at East Hartford, Connecticut, with the engine's first flight in June 1968 mounted on a

Boeing B-52 The Boeing B-52 Stratofortress is an American long-range, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the United States Air ...

E which served as a JT9D flying

testbed A testbed (also spelled test bed) is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies. The term is used across many disciplines to describe experimental res ...

. In 1968, its unit cost was $800,000, $ million today.

Design

The JT9D introduced advanced technologies in structures, aerodynamics, and materials, which included

titanium alloy Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness (even at extreme temperatures). They are light in weight, have extraordinary corrosion resista ...

s and nickel alloys, to improve fuel efficiency and reliability compared to the Pratt & Whitney JT3D earlier turbofan. The engine featured a single-stage fan, a three-stage low-pressure compressor, and an eleven-stage high-pressure compressor coupled to a two-stage high-pressure turbine and four-stage low-pressure turbine. The JT9D-3, the earliest certified version of the engine, weighed and produced thrust. Pratt & Whitney faced difficulties with the JT9D design during the Boeing 747 test program. Engine failures during the flight test program resulted in thirty aircraft being parked outside the factory with concrete blocks hanging from the pylons, awaiting redesigned engines. Boeing and Pratt & Whitney worked together in 1969 to solve the problem. The trouble was traced to ovalization, in which stresses during takeoff caused the engine casing to deform into an oval shape resulting in rubbing of high-pressure turbine blade tips. This was solved by strengthening the engine casing and adding yoke-shaped thrust links.Flight International, 13 November 1969, p.749 JT9D engines powering USAF Boeing E-4A airborne command posts were designated F105.

Variants

All variants have the same number of compressor and turbine stages.

Applications

* Airbus A300 * Airbus A310 * Boeing 747-100/200/300/ SP *

(early models) *

Boeing RC-1 The Boeing RC-1, short for "Resource Carrier 1", was a design for an enormous cargo aircraft intended to haul oil and minerals out of the northern reaches of Alaska and Canada where ice-free ports were not available. It was optimized for short-ha ...

* McDonnell Douglas DC-10-40

Specifications (JT9D-7R4)

References

External links

* {{DEFAULTSORT:Pratt and Whitney JT9D High-bypass turbofan engines

JT9D The Pratt & Whitney JT9D engine was the first high bypass ratio jet engine to power a wide-body airliner. Its initial application was the Boeing 747-100, the original "Jumbo Jet". It was Pratt & Whitney's first high-bypass-ratio turbofan. Deve ...

1960s turbofan engines