SFC

S

surfCRQ

Well-Known Member
I'm writing a paper on fuel efficiency in aviation...
Looking for the numbers for specific fuel consumption on Boeing fleet aircraft engines:
JT3 (J57), JT8D, PW2037, CFM56, JT9.
Also is there a website where all of this is posted. Ive searched for 2 hours, been on boeing, P&W, wikipedia, airliners... can't seem to find it.
Also bypass ratio's would be good as I am trying to illustrate an increase in fuel efficiency and thrust over time. Thanks yall.
 
I'm skeptical of the SFC values on that page. Typical TSFCs during cruise for everything from a CFM56-7 to a CF6-80C2 are in the range of 0.38-0.42 lb/lb·h.

However, specific range will vary much more by airframe. For instance, compare an MD-80 and a mid-size 737NG. They have roughly the same number of seats, but one burns more fuel than the other for the same trip. An MD-80 will do about 0.064 nm/lb (16 lbs of fuel per nm; a linear approximation of the trip-average), while the 737 can do the same trip at around 0.078 nm/lb (13 lb/nm).

A larger aircraft, like a 767 averages about 0.038 nm/lb (26 lb/nm). However if you look at the fuel consumption per seat, the 767 is still a better deal. The 737 has 145 seats, so that's 0.00054 lb/seat-mile. The 767 has 220 seats, which works out to about 0.00017 lb/seat-mile (68% less). That trip Dough makes between New York and Paris might burn around 82,000 lbs (although westbound will burn between 15% to 20% more than going east).

There are other factors to skew those numbers. For example, if the 737 spent a similar portion of its trip at cruise as the 767 the gap could be smaller. Or maybe the passenger load factors are consistently higher on the 737, so you have to penalize the 767 for having fewer revenue seats.

For the MD-80 and 737 trips the linear approximation needs an additional bias of between 1500-2000 lbs to figure the trip fuel (rule-of-thumb). E.g., a 1000 nm 737 trip should use about 14,750 lbs (= 1000nm * 13lb/nm + 1750 lb).
 
-I may have to keep this thread open with other questions as i write this paper.:
At what bypass ratio is a turbofan designated as 'high bypass'?
 
If you are near a university you might try their engineering library. Later I will look at my turbine propulsion books to see if they have some charts for you.
 
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