December 21, 200520 yr Hi guys,I'm wondering, what is the reasoning for Boeing to offer 3 engine variants on the 744? In the sim itself it seems that the performance of the enignes (thrust, fuel consumption etc) is pretty similar. However there must be some real-world differences or else why would you offer a choice?Anyone know the answer(s)? Mark Adeane - NZWN
December 21, 200520 yr Hi all,Here are some technical specifications for the Boeing 747-400 engines:Pratt & Whitney PW406263,300 lb Rolls-Royce RB211-524H2-T59,500 lb General Electric CF6-80C2B5F62,100 lb Ken.
December 21, 200520 yr Another difference between the GE varient with the PW and RR, is that the RR and PW varients are a 3 stage (3 shaft) engine, and the GE is only 2.GE Engines, measure its power in N1, which is the speed of the LP Fan, which is the one you see when you look into the front of the engine, where as the RR and PW engines, measure in EPR or Engine Pressure Ratio, which means that the measure the pressure of the intake air at the first stage compressor, and ratio it over a pressure either after the final compressor section, or at the Turbine.The RR RB211 has the lowest mature fuel burn, over its counterparts, and this varient of the RB211 is also interchangeable with the B767, which only affects Qantas (BA A/C on lease) and BA.Cheers
December 21, 200520 yr Hi Iain,Yes it is very interesting how the BA 744s and 763s use exactly the same engine, and can be swapped with no issues.With GE and PW are there similar situations with any other carriers where the engines can be swapped like that?Best regards,http://www.bootus.co.uk/pilotinfo.gif Armen L CholakianPMDG Sound Engineer
December 21, 200520 yr Even if they can't be directly swapped, a lot of manufactures try to use as many of the same parts so they don't have to increase production facilities more then they need to.----------------------------------------------------------------John MorganReal World: KGEG, UND Aerospace Spokane Satillite, Private ASEL 141.2 hrs, 314 landings, 46 inst. apprs.Virtual: MSFS 2004"There is a feeling about an airport that no other piece of ground can have. No matter what the name of the country on whose land it lies, an airport is a place you can see and touch that leads to a reality that can only be thought and felt." - The Bridge Across Forever: A Love Story by Richard Bach John Morgan "There is a feeling about an airport that no other piece of ground can have. No matter what the name of the country on whose land it lies, an airport is a place you can see and touch that leads to a reality that can only be thought and felt." - The Bridge Across Forever: A Love Story by Richard Bach
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