General Electric GEnx

from Wikipedia, the free encyclopedia

The General Electric GEnx ( G eneral E lectric n e x t-generation ) is a turbofan -Triebwerk that of General Electric initially only on behalf of the aircraft manufacturer Boeing for the Boeing 787 , then also for the original versions of the Airbus A350 developed has been. However, Airbus stopped developing the original versions of the A350. It is still unclear whether the GEnx will be used on some or all versions of the Airbus A350 XWB, which has now been developed by Airbus. In the meantime, however, Boeing has selected the GEnx as the exclusive engine for the Boeing 747-8 . The GEnx is intended to replace the General Electric CF6 series.


General Electric GEnx at the 2009 Paris Air Show

The GEnx uses some of the proven technologies of the General Electric GE90 , such as composites. It was originally developed for the Boeing 787 , where it competes with the Rolls Royce Trent 1000 . For the first time in commercial aviation, the two different engine types from the two manufacturers on the Boeing 787 can be exchanged at any time, so that they can be integrated into a fleet that uses the other engine type by changing the engine.

For the first time, bleed air systems are no longer used in either engine , for example to supply the air conditioning system. Instead, this should be done by two starters / generators with 250 kVA each per engine.

The versions of the GEnx for the Boeing 787 develop 236–334  kN of thrust and, compared to today's engines, consume 20 percent less fuel and are significantly quieter.

In addition, Boeing selected a variant of the GEnx with 298 kN thrust as the exclusive drive for the two versions of the Boeing 747-8 . However, this releases bleed air for the 747's bleed-air-based systems.

It is still unclear whether a GEnx version with bleed air delivery will be used on the Airbus A350 XWB . Although GE was the main supplier to the original Airbus A350, there is still no contract to supply some or all of the variants of the Airbus A350 XWB .

On March 19, 2006, a bleedless variant of the GEnx generated 378 kN of thrust in the first test run of the engine type. On February 22, 2007, the approximately three-hour first flight took place on the flying test bench (a 747) from GE.

The 40 or so engines built in the Block 4 stand of the GEnx-1B did not achieve the required fuel consumption values ​​by mid-2011. With a Performance Improvement Package 1 (PIP-1), in which the number of blades is increased in several stages, this should be improved by 1.4% and thus only about one percent above the specifications. The engines with PIP-1 received their approval in August 2011.

In the long term, a PIP-2 should reduce fuel consumption to the specified values ​​and at the same time increase the thrust of the engine. This should be done through an additional stage in the low-pressure compressor and in the low-pressure turbine, through larger fan blades and other changes to the engine. The modifications were first tested in December 2010 and have been part of the production standard for the respective engines since 2013.

Engines built before this period should be converted during the next scheduled maintenance. All modifications should be completed by 2020.


Although the GEnx is derived from the GE90, the GEnx uses a number of weight-saving innovations:

  • Manufacture of the fan blades from composite materials, with leading edges made of titanium
  • Manufacture of the engine housing from composite materials

The following technologies are intended to reduce fuel consumption:

  • a bypass ratio of 9.5: 1. This also reduces noise emissions
  • a high pressure compressor based on the GE90-94B with a compression ratio of 23: 1
  • opposing shaft systems N1 (Low Pressure) and N2 (High Pressure)
  • Combustion chamber with improved internal air flows that reduce polluting emissions
  • With the Boeing 787: no more bleed air for the air conditioning or similar, only for the anti-ice system of the engine intake

Maintenance costs and wear should be reduced by the following:

  • fewer turbine parts
  • a lower internal temperature through more efficient cooling techniques
  • easier removal of the fan including the fan housing from the rest of the engine

All of these technologies are said to result in fuel savings of at least 15 percent compared to the GE CF6-80C2B1F . The direction of rotation of the fan is a special feature. In contrast to all other GE engines, the N1 low-pressure shaft - i.e. the fan - rotates to the left (viewed in the direction of flight). Because the two waves are rotating in opposite directions, the N2 high-pressure wave or the core engine has the classic direction of travel of large American engines, namely clockwise as seen in the direction of flight. The fan of the GEnx thus has a direction of rotation that was previously only seen on Rolls-Royce large engines.

Chevrons on the exhaust nozzle and engine cowling are intended to reduce noise emissions.


Boeing 787

Engine variants: GEnx-1B-54 (787-3), GEnx-1B-64 (787-8), GEnx-1B-70 (787-9)

The GEnx on an Air India Dreamliner

At first, orders for Boeing 787s with GEnx engines took off after the previous General Electric monopoly on the Japanese market with orders for Rolls-Royce engines for All Nippon Airways ' Boeing 787 Models had fallen, it initially looked bad for GE, as ANA also played a trendsetter role. Meanwhile, however, GE leads again with 52 percent of the orders for 787 models with GE engines (status: September 2007).

The GEnx-1B received its approval from the US Aviation Administration in March 2008.

Boeing 747-8

A GEnx with the fairing open on the Boeing 747-8I prototype. The nozzle and engine cowling have the jagged chevrons .

Engine variant: GEnx-2B-67

The Boeing 747-8 is only available with GEnx engines in both cargo and passenger versions. For this variant, the fan diameter of the GEnx was reduced from 2.82 m to 2.67 m. The bypass ratio is 8.6: 1 (9.1 to 9.6: 1 for the other variants, depending on the thrust). The engine was approved in August 2010.

Airbus A350

Engine variant: GEnx 72A

GE initially benefited from being named the main supplier for the A350 series, winning engine orders for 105 A350s (through June 17, 2005). On July 17, 2006, however, Airbus announced the completely redesigned A350 XWB version, this time with Rolls Royce as the main supplier for all three versions. Airbus is still negotiating with General Electric about equipping it with GE engines. However, according to General Electric, the GEnx should be available for the Airbus A350-800 and possibly also for the Airbus A350-900. According to General Electric, the A350-1000 will not be able to be equipped with the GEnx, as GE has an exclusive contract with Boeing for the 777-300ER in the size of the A350-1000 .

Technical specifications

The technical data are as follows:

Parameter GEnx-1B-54 (787-3) GEnx-1B-64 (787-8) GEnx-1B-70 (787-9) GEnx-2B-67 (747-8)
Thrust: 255.30 kN 298.00 kN 321.60 kN 299.80 kN
Length: 4,950 m 4,950 m 4,950 m 4,464 m
Fan diameter: 2.822 m 2.822 m 2.822 m 2,667 m
Weight: 6,126 kg 6,126 kg 6,126 kg 5,540 kg
Bypass ratio: 9.6: 1 9.2: 1 9.1: 1 8.6: 1
Total pressure ratio at start: 36.1: 1 41.4: 1 44.3: 1 43: 1
Fan stages: 1 1 1 1
Low pressure compressor stages: 4th 4th 4th 3
High pressure compressor stages: 10 10 10 10
High pressure turbine stages: 2 2 2 2
Low pressure turbine stages: 7th 7th 7th 6th


  1. Aviationindustriegroup ( Memento of the original from September 27, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot /
  2. ^ General Electric Performs First Run of New GEnx Engine . Flight International . March 21, 2006.
  3. a b Passed the practical test: GE Aviation GEnx on duty . In: FLIGHT REVIEW . ( [accessed July 1, 2017]).
  4. Chevron nozzles reduce noise on Lufthansa's Boeing 747-8 - - Das Fliegermagazin
  5. [1] In: Flight Revue . March 31, 2008.
  6. EASA TCDS "IM.E.102" (TCDS = Type Certificate Data Sheet)  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link /