Fuel efficiency of boeing 747?

Question

Fuel efficiency of boeing 747?

Answer 1

fuel flow at 35,000 feet at mach 0.80 will be between 5,000-7,000 pounds per hour per engine

A pilot told be 6,000 PPH per engine at cruise altitude of 35,000 feet. Didn't say speed.

other adverts say it gets about 80-100 miles per passenger per gallon.

Aviophag? maybe answer this one?

Answer 2

Can't be any worse than my Dodge Ram truck!  Sheesh!!!!

Answer 3

Like smoothask said for what looks like an answer to your vague question. . One thing we do know is that the new jet engines coming offline from General Electric Corp are going to be significantly higher in fuel efficiency compared to jets in the past.  

Answer 4

You will have to specify at what altitude and airspeed. The fuel flow will vary significantly between 30,000 feet and 40,000 feet, as well as between M0.80 and M0.85.

I'm sure an average can be provided if you do not need an exact number.

Answer 5

I'll join in saying that the question is too vague to merit a definitive answer, but I'll take a stab.

First, it depends on what is meant by "fuel efficiency". What units are you looking for?  Pounds per hour?  Gallons per hour?  Miles per gallon?  Miles per pound?  Gallons per mile?  Passenger miles per pound?  Passenger gallons per mile?  These are all different ways of quantifying fuel efficiency.

The common way that aircraft manufacturers and the airline companies market the fuel efficiency of their aircraft is in passenger miles per gallon, which means how many miles the aircraft can travel per gallon of fuel, per passenger on board.  This value depends on what the other answerers said above (i.e., depends on airspeed, altitude, and other flight conditions such as gross weight, groundspeed, etc) and also depends on the seating configuration (or more directly, how many passengers are on board on a full flight).

But to answer your question as a very rough-cut rule-of-thumb estimate for the 747-400, they burn in the ballpark of about 5 gallons of fuel per mile of travel, or about 100 miles per gallon per passenger on board.