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Pratt & Whitney 4077
Rolls-Royce Trent 877
General Electric GE90-77B
Pratt & Whitney 4090
Rolls-Royce Trent 895
General Electric 90-94B
The Trent 900 is the world’s cleanest high-thrust engine, measured by emissions per pound of thrust.
Originally designed for the 777-200LR and 777-300ER (both part of the 777X project), this engine comes in two thrust ratings, 104,000 and 114,000 lbf (463 to 507 kN), and has been tested up to 117,000 lbf (520 kN).
Rolls-Royce offered the 8104 to Boeing earlier than other manufacturers. Boeing had a requirement that the participating engine developer assume a risk-sharing role on the overall 777X project. Rolls-Royce was unwilling to do so, and thus Boeing chose advanced developments of the GE90, the GE90-110B and GE90-115B. This relegated the 8104 to the role of demonstrator engine. It featured swept-back fan blades and a host of new technologies such as contra-rotating spools.
In 1944 the US published specification AN-F-32 for JP-1, a -60C freezing point kerosene. The freezing point so limited availability that is was soon superseded by various wide cut fuels; JP-2 (1945), JP-3 (1947) and JP-4 (1951 - avtag, NATO F-40). These wide cut fuels are mixtures of naphtha and kerosene which greatly increase availability. The first British jet engine fuel specification, RDE/F/KER (Provisional), was introduced by the end of World War II and covered what was virtually an illuminating kerosene. After a few amendments, RDE/F/KER was superseded in 1947 by D.Eng.RD. (DERD) 2482 and this was in turn reissued from time to time with increasingly stringent requirements.
This specification became obsolete in 1965 when it was replaced by D.Eng.RD 2494, the predecessor to current commercial (Defence Standard 91-91 and British military (Defence Standard 91-87) specifications. Even though the first US jet engines were direct copies of early British designs, these pioneering jet fuel specifications differed significantly in volatility, freezing point, specific gravity, sulfur and aromatic limits. The US specification was most likely derived from the aviation gasoline specification, while the British specification reflected the properties of illuminating kerosene.
Designed around customers' needs, the GEnx represents a giant leap forward in propulsion technology. The engine will use the latest generation materials and design processes to reduce weight, improve performance and lower maintenance.
The GEnx will deliver 15 percent better specific fuel consumption than the engines it replaces, helping operators save whenever they fly. It is designed to stay on wing 30 percent longer, while using 30 percent fewer parts, greatly reducing maintenance. The GEnx's emissions will be as much as 95 percent below current regulatory limits, ensuring clean compliance for years to come, and it will be the quietest, most passenger-friendly commercial engine ever produced.
All of the these improvements are thanks to the incorporation of advanced and proven technologies from other engine families and on-going R&D programs. Like lightweight, durable composite materials and specialized coatings. An innovative, clean-burning combustor, a counter-rotating architecture, and a fan module that's virtually maintenance free.
It is a low-risk, high-value solution to the challenges our customers face everyday. It is the GEnx.
Originally posted by sminkeypinkey
I can well remember those in my family in the RAF commenting that US jets were at times very visible because they were so smokey, I expect things have improved markedly where they really need to militarily but it would be interesting to see a formal comparison with the civil jets in this regard.
Originally posted by American Mad Man
I'd be interested if those comments (about US jets being smokey) were made based on the F-4.
Pratt & Whitney
Pratt & Whitney