Ask any plane spotter about the General Electric GE90-155B engines and you will get a universal thumbs-up. The largest engines fitted on any commercial jet, two GE90’s power every Boeing 777 made today; the -300ER, the -200LR, or the freighter.
|Put the engine size in perspective. Compare the ground engineer near the nose wheel.|
To give you an idea of size, the diameter of the engine (11 ft 3 in or 3.429 m) is just a little less than the fuselage diameter of the Boeing 737, and at take-off thrust the engine swallows more than two million cubic feet of air per minute. More technical details can be read here.
Apart from its size, what spotters love about the engine is the unique “moaning” sound it makes the engine turbine fired at start-up.
All commercial jet engines today, are started using compressed air. The compressed air is produced by the auxillary power unit (APU) located in the tail of the aircraft and fed via ducts to the engines. This are blows the engine blades around through a series of gearbox, shafts, and starter. When the engine blades are sped up to a certain point, fuel is injected into the engine and ignited. At this moment the GE90 produces its signature moan and the engine starts.
This is what the engine start-up sounds like from outside
This is from inside the cabin