General Electric GEnx

The General Electric GEnx (General Electric Next-generation) is an advanced dual rotor, axial flow, high-bypass turbofan jet engine

Jet engine

A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...

 in production by GE Aviation for the Boeing

Boeing

The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...

 787 and 747-8

Boeing 747-8

The Boeing 747-8 is a wide-body jet airliner developed by Boeing Commercial Airplanes. Officially announced in 2005, the 747-8 is the fourth-generation Boeing 747 version, with lengthened fuselage, redesigned wings and improved efficiency...

. The GEnx is intended to replace the CF6

General Electric CF6

The General Electric CF6 is a family of high-bypass turbofan engines produced by GE Aviation. A development of the first high-power high-bypass jet engine available, the TF39, the CF6 powers a wide variety of civilian airliners. The basic engine core formed the basis for the LM2500, LM5000, and...

 in GE's product line.

Design and development

The GEnx and the Rolls-Royce Trent 1000 were selected by Boeing following a run-off between the three big engine manufacturers. The GEnx uses some technology from the GE90

General Electric GE90

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 lbf . It was first introduced in November 1995 on British Airways' 777s, and is available only on the 777...

 turbofan, including composite fan blades, and the smaller core featured in earlier variants of the engine. The engine carries composite technology into the fan case.

Both engine types will have a standard interface with the aircraft, allowing any 787 to be fitted with either GE or RR engines at any time. The engine market for the 787 is estimated at US$40 billion over the next 25 years. A first is the elimination of bleed air

Bleed air

Bleed air in gas turbine engines is compressed air taken from within the engine, after the compressor stage and before the fuel is injected in the burners. While in theory bleed air could be drawn in any gas turbine engine, its usage is generally restricted to jet engines used in aircraft...

 systems using high temperature/high pressure air from the propulsion engines to power aircraft systems such as the starting, air-conditioning and anti-ice systems. The GEnx and the Trent 1000 allow a move towards the electric airplane.

The GEnx is expected to produce thrust from 53000 to 75000 lbf (235.8 to 333.6 kN) with first tests commencing in 2006 and service entry by 2008 (now delayed by 787 deliveries). Boeing predicts reduced fuel consumption of up to 20% and significantly quieter engines than current turbofans. A 66500 lbf (295.8 kN) thrust version (GEnx-2B67) will be used on the 747-8. Unlike the initial version, for the 787, this version has a traditional bleed air system to power internal pneumatic and ventilation systems. It will also have a smaller overall diameter than the initial model to accommodate installation on the 747.

General Electric began initial test runs of the bleedless GEnx variant on 19 March 2006. The first flight with one of these engines took place on 22 February 2007, using a Boeing 747

Boeing 747

The Boeing 747 is a wide-body commercial airliner and cargo transport, often referred to by its original nickname, Jumbo Jet, or Queen of the Skies. It is among the world's most recognizable aircraft, and was the first wide-body ever produced...

-100, fitted with one GEnx engine in the number 2 (inboard LH) position.

Technology

Despite being derived from the GE90, the GEnx features a number of weight-saving innovations:

• Fan diameter of 111 in (2.8 m) for the 787-8 and 105 in (2.7 m) for the 747-8.
• Composite fan blades with titanium leading edges.
• Fan case of composite material which reduces weight and thermal expansion.
• Titanium aluminide
  Titanium aluminide
  Titanium aluminide, TiAl, is an intermetallic chemical compound. It is lightweight and resistant to oxidation and heat, however it suffers from low ductility. The density of gamma TiAl is about 4.0 g/cm³. It finds use in several applications including automobiles and aircraft...
  
   stage 6 and 7 low pressure turbine blades.

Fuel burn reduction technologies include:

• Fan bypass ratio of 19:2, which also helps reduce noise.
• High pressure compressor based on GE90-94B, with 23:1 pressure ratio and only 10 stages. Also, shrouded guide vanes reduce secondary flows.
• Counter-rotating spools for the reaction turbine
  Turbine
  A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
  
  s to reduce load on guide vanes.
• Lean TAPS (twin annular premixed swirler) combustor
  Combustor
  A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, combustion chamber or flame holder. In a gas turbine engine, the combustor or combustion chamber is fed high pressure air by the compression system. The...
  
   to reduce environmentally-harmful emissions with improved airflow to prevent back flash.

Among features to reduce maintenance cost and increase engine life are:

• Spools with lower parts count achieved by using blisk
  Blisk
  A blisk is a single engine component consisting of a rotor disk and blades, which may be either integrally cast, machined from a solid piece of material, or made by welding individual blades to the rotor disk. The term is used mainly in aerospace engine design. The word is a portmanteau of blade...
  
  s in some stages and low blade counts in other stages and by using a low number of stages.
• Internal engine temperatures reduced by using more efficient cooling techniques.
• Debris extraction within the low pressure compressor guards high pressure compressor.

All of these yield a fuel burn said to be 15% better than GE's CF6-80C2 engines for widebody aircraft.

Specifications

Data from .

This engine is a dual rotor, axial flow, high bypass ratio turbofan. The 10-stage high pressure compressor is driven clockwise (Aft Looking Forward) by a 2-stage high pressure turbine. The single stage fan and 4-stage low pressure compressor are driven counterclockwise (Aft Looking Forward) by a 7-stage low pressure turbine. The engine control system includes a Full Authority Digital Engine Control (FADEC)

FADEC

Full Authority Digital Engine Control is a system consisting of a digital computer, called an electronic engine controller or engine control unit , and its related accessories that control all aspects of aircraft engine performance...

, which has an aircraft connection for digital communication. An engine monitoring unit (EMU) provides vibration level signals to the aircraft.
generated with :de:Wikipedia:Helferlein/VBA-Macro for EXCEL tableconversion V1.7<\hiddentext>>

Engine Model	Arrangement						Performance									Dimensions (inch) and Weight (lb)				Certified (FAA)	Application	Entry Into Service	Emissions
	Fan diameter (in)	Fan	LPC	HPC	LPT	HPT	Thrust Max (lbf)		Flat-Rated Temp C		Overall Pressure Ratio (OPR)	Fan Bypass Ratio (BPR)	Air flow (kg/s)	SFC (max power)	T/W Ratio	Length	Max Envelope		Weight (Dry)				CO	NOx	HC
							Take-off (5 min)	Max Cont.	Take-off	Max Cont. | Width | Height
GEnx-1B54	111	1	4	10	7	2	57,400	56,300	ISA+15	ISA+10	36.0				4.48	194.0	139.0	137.0	12,822	Mar 31, 2008 | B787-3
GEnx-1B58	111	1	4	10	7	2	61,000	56,300	ISA+15	ISA+10					4.76	194.0	139.0	137.0	12,822	Mar 31, 2008 | B787-3,-8
GEnx-1B64	111	1	4	10	7	2	67,500	61,500	ISA+15	ISA+10	41.0				5.23	194.0	139.0	137.0	12,822	Mar 31, 2008 | B787-8,-9
GEnx-1B67	111	1	4	10	7	2	69,400	61,500	ISA+15	ISA+10	43.0				5.41	194.0	139.0	137.0	12,822	Mar 31, 2008 | B787-8,-9
GEnx-1B70	111	1	4	10	7	2	72,300	66,500	ISA+15	ISA+10	43.0	9.6:1			5.64	194.0	139.0	137.0	12,822	Mar 31, 2008 | B787-9
GEnx-2B67	105	1	3	10	6	2	67,400	58,500			43.0	8.6:1				185.0	127.0	127.0	12,400	July 22, 2010 | B747-8

Note: Data for sea level static, standard pressure, no customer bleed or customer horsepower extraction, ideal inlet, 100% ram recovery, production aircraft flight cowling, production instrumentation, fuel lower heating value of 18,400 BTU/lb.

Note: 787-3 plans were cancelled on December 13, 2010 due to low demand.

Specifications (GEnx-1B64)

See also

External links

• GE GEnx website
• First flight with this engine
• FAA Type Certificate