General Electric GE90

GE90
GE90-115B
Type	Turbofan
Manufacturer	GE Aviation
First run	1995
Major applications	Boeing 777
Unit cost	$24 million (2009 USD)[citation needed]
Developed into	General Electric GEnx

General Electric GE90 is a family of high-bypass turbofan aircraft engines built by GE Aviation for the Boeing 777, with thrust ratings ranging from 74,000 to 115,000 lb_f (329 to 512 kN). It was first introduced in November 1995 on British Airways' 777s, and is available only on the 777. The engine is one of three options for the 777-200, -200ER, and -300, and the exclusive engine of the -200LR, -300ER, and -200F.

Design and development

NASA GE90 airflow simulation

The GE90 was launched in 1990 by GE Aviation associated with Snecma (France), IHI (Japan) and Avio (Italy). Developed from the 1970s NASA Energy Efficient Engine, the 10-stage high pressure compressor develops a pressure ratio of 23:1 (an industry record) and is driven by a 2-stage, air-cooled, HP turbine. A 3-stage intermediate pressure compressor, situated directly behind the fan, supercharges the core. The fan/IPC is driven by a 6-stage low pressure turbine.

The higher thrust variants, GE90-110B1 and -115B, have a different architecture from the earlier marks of GE90, with one stage removed from the HP compressor (probably from the rear, to increase core size), with an extra stage added to the IP compressor to maintain/increase overall pressure ratio to achieve a net increase in core flow. General Electric did a similar re-staging exercise when they upgraded the CF6 from the -6 to the higher thrust -50. However, this thrust growth route is expensive, since all the downstream components (e.g. turbines) have to be larger (in flow capacity). So it is hardly surprising that GE sought (and received) sole engine supplier status with the -115B on the Boeing 777-300ER. The fan is an advanced, larger diameter unit made from composite materials and is the first production engine to feature swept rotor blades. Although the larger fan in itself would produce a higher static thrust, an increase in core size and, thereby core power, was required to improve the net thrust at normal flight speeds.

At least one technical paper^{[citation needed]} presented on behalf of one of GE's project partners indicates that further thrust improvement programs will be promoted should a market for higher thrusts arise. For comparison purposes, the Boeing 747-400's largest engines produce 63,300 lb_f (289 kN) of thrust.

In October 2003, a Boeing 777-300ER broke the ETOPS record by being able to fly five and a half hours (330 minutes) with one engine shut down. The aircraft, with GE90-115B engines, flew from Seattle to Taiwan as part of the ETOPS certification programme.

The GE90 series are physically the largest engines in aviation history, the fan diameter of the original series being 312 cm (123 in). The largest variant, the GE90-115B, has a fan diameter of 325 cm (128 in). As a result, GE90 engines can only be airfreighted in assembled form by outsize cargo aircraft such as the Antonov An-124 Condor, presenting unique problems if, due to emergency diversions, a 777 were stranded in a place without the proper spare parts. If the fan is removed from the core, then the engines may be shipped on a 747 Freighter. Apart from its size, the GE90-115B is powerful enough to fully operate GE's Boeing 747 testbed on its own power during a maximum thrust low speed flight testing on board the aircraft

Derivatives

The GEnx engine, that has been developed for the Boeing 787 Dreamliner and 747-8, is derived from the smaller (i.e. earlier) core variant of the GE90, but features a fan with swept rotor blades. GE Aviation has also set up a cooperative venture with Pratt & Whitney, named Engine Alliance, underwhich the companies have developed an engine for the Airbus A380, called the GP7000, from the larger GE90-110B/115B core.

GE has also announced studies on a slightly smaller derivative engine, dubbed the GE9X, to power the new Boeing 777-8x/9x aircraft. It will feature a fan diameter decrease from the 135 in (343 cm) of the GE90-115B to 128 in (325 cm) and an overall thrust decrease of 15,800 lbf to a new rating of 99,500 lbf per engine.

Operational history

A GE90-110B1 mounted on an Air Canada Boeing 777-200LR inflight over Siberia

The first General Electric-powered Boeing 777 was delivered to British Airways on November 12, 1995; the aircraft, with two GE90-77Bs, entered service five days later. Initial service was affected by gearbox bearing wear issues, which caused the airline to temporarily withdraw its 777 fleet from transatlantic service in 1997. British Airways' aircraft returned to full service later that year, and General Electric subsequently announced engine upgrades.

Records

According to the Guinness Book of Records, at 127,900 lb_f (569 kN), it holds the record for the highest thrust (though it is rated at 115,300 lb_f (513 kN)). This thrust record was accomplished inadvertently as part of a one-hour, triple-red-line engine stress test. In order to accommodate the increase in torsional stresses an entirely new steel alloy (GE1014) had to be created and then machined to extreme tolerances. The new record was set during testing of a GE90-115B development engine at GE Aviations' Peebles Test Operation, which is an outdoor test complex outside Peebles, Ohio. It eclipsed the engine's previous Guinness world record of 122,965 pounds of thrust.

On November 10, 2005, the GE90 entered the Guinness World Records for a second time. The GE90-110B1 powered a 777-200LR during the world's longest flight by a commercial airliner, though there were no fare-paying passengers on the flight, only journalists and invited guests. The 777-200LR flew 13,422 miles (21,601 km) in 22 hours 42 minutes, flying from Hong Kong to London "the long way": over the Pacific, over the continental U.S., then over the Atlantic to London. (The longest flight by a commercial airliner with passengers is 18.5 hours, flown by an Airbus A340-500 aircraft on a daily non-stop flight from Newark to Singapore on Singapore Airlines. See Singapore Airlines Flight 21)

Applications

• Boeing 777

Variants

A General Electric GE90 turbofan mounted on Saudi Airlines' Boeing 777-200ER, at the King Abdulaziz International Airport.

GE90-76B 

rated at 76,000 lb_f (338.1 kN)

GE90-77B 

rated at 77,000 lb_f (342.5 kN)

GE90-85B 

rated at 85,000 lb_f (378.1 kN)

GE90-90B 

rated at 90,000 lb_f (400.3 kN)

GE90-92B 

rated at 92,000 lb_f (409.2 kN)

GE90-94B 

rated at 93,700 lb_f (416.8 kN)

GE90-110B1 

rated at 110,100 lb_f (489.3 kN)

GE90-115B 

rated at 115,300 lb_f (514 kN)

Specifications (GE90-94B)

The second most powerful variant (GE90-110B1), mounted on a Boeing 777-200LR

General characteristics

• Type: axial flow, twin-shaft, bypass turbofan engine
• Length: 287 in (7,290 mm)
• Diameter: overall: 134 in (3,404 mm); fan: 123 in (3,124 mm)
• Dry weight: 16,644 lb (7,550 kg)

Components

• Compressor: axial: 1 wide chord fan, 3 low pressure stages, 10 high pressure stages
• Turbine: axial: 6 low pressure stages, 2 high pressure stages

Performance

• Maximum thrust: max at sea level: 93,700 lb_f (416.8 kN)
• Overall pressure ratio: 42:1
• Thrust-to-weight ratio: approx. 5.6:1

Specifications (GE90-115B)

A GE90-115B mounted on the #2 pylon of GE's Boeing 747 flight test aircraft at the Mojave Airport. GE90-115B was able to keep this 747 airborne by itself, while all three smaller engines were deliberately shut-down in flight. The -115B is more than twice as powerful as the Pratt and Whitney JT9D engines that occupy the other pylons.

General characteristics

• Type: axial flow, twin-shaft, bypass turbofan engine
• Length: 287 in (7,290 mm)
• Diameter: overall: 135 in (3.429 m); fan: 128 in (3.251 m)
• Dry weight: 18,260 lb (8,283 kg)

Components

• Compressor: axial: 1 wide chord swept fan, 4 low pressure stages, 9 high pressure stages
• Turbine: axial: 6 low pressure stages, 2 high pressure stages

Performance

• Maximum thrust: max at sea level: 115,540 lb_f (514 kN) ; world record set at 127,900 lb_f (568,9 kN) 827 feet above sea level
• Overall pressure ratio: 42:1
• Thrust-to-weight ratio: approx. 6.3:1

See also

Related development

• General Electric GEnx
• Engine Alliance GP7000
  

Comparable engines

• Rolls-Royce Trent 800
• Pratt & Whitney PW4000
  

Related lists

• List of aircraft engines
  

Footnotes

Bibliography

• Eden, Paul, ed (2008). Civil Aircraft Today: The World's Most Successful Commercial Aircraft. London: Amber Books Ltd. ISBN 1-84509-324-0. 
• Norris, Guy; Mark Wagner (1999). Modern Boeing Jetliners. Minneapolis, Minnesota: Zenith Imprint. ISBN 0-7603-0717-2. 

External links

• GE90 page on geae.com
• It's Great Design Too: World's Biggest Jet Engine Fan Blade at The Museum of Modern Art.