BOEING747400 From United States of America, joined Sep 2001, 319 posts, RR: 0 Posted (10 years 2 months 3 weeks 5 days 14 hours ago) and read 2085 times:
Can anybody please explain to me how and why the 744 comes with different range numbers with various engines? What does PW 4056 have that makes it go farther than the GE B1F and RR RB211? Also, what does GE B1F have that makes it go farther than RR RB211 as well? I would like to understand how does an aircraft engine produce more range than its competitors. Thanks for any information.
Buckfifty From Canada, joined Oct 2001, 1314 posts, RR: 21 Reply 1, posted (10 years 2 months 3 weeks 5 days 14 hours ago) and read 2062 times:
More range...
a) Engine Specific Fuel Consumption. (Usually measured as the fuel flow per unit thrust the engine produces. The lower the better.)
b) Engine weight. (Or engine thrust/weight ratio.)
c) Engine thrust rating (More thrust usually means more payload, which usually means more fuel can be carried. However, this is not always the case.)
As to the individual differences between the engines, I'll let someone else who actually knows answer that question for you...
Cx flyboy From Hong Kong, joined Dec 1999, 6341 posts, RR: 56 Reply 2, posted (10 years 2 months 3 weeks 5 days 3 hours ago) and read 1783 times:
Some of you may be wondering why an airline doesn't simply go for the engine that gives the most range, as implied fuel efficiency saves money and therefore is cheaper to run? Why would anyone ever buy the Rolls Royce for example?
Purchase price of the engines, spares availability and price, ease of maintenance, performance in specific areas of operation may be different as well. Hot and high performance of one engine may be far superior to another. To an airline flying out of a regularly hot, humid and high airport, this is important, even if the cost of the engine and range may be less. For an airline that doesn't push the range limits of the aircraft on it's route network, the extra range offered by one engine over another may not be important. To another airline, this extra range may be very important. Different thrust ratings of the engines may lead to slightly different take-off weights as well. The extra take-off weight may be appealing to one airline, and not so appealing to another airline.
Sorry to to slightly off topic, but I used to wonder why an airline would choose an engine that appeared not to be the most efficient over another, so maybe someone else out there is wondering the same thing.
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