Bryan Wood

Bryan Wood

Well Known Member
Not RV related, but interesting. Sunday my hanger neighbor dropped in to say hello and to kick tires. He is a retired 747-400 captain who flew the San Francisco to Sydney route at the time he retired. Always being curious about the fuel consumtion of one of these planes I asked him how much fuel it takes to go one way to Austrailia.

"For the first hour the 400 burns an honest 25,000 lbs. of fuel per hour." As the 14 hour flight plays out the burn begins to go down slightly, but starts to become more noticable around 10 hours out. By the last hour the burn is down around 18,000 lbs. per hour.

When I got home still not able to put into perspective fuel burns in pounds the calculator came to the rescue and translated it to 62 gallons per minute for approx. 10 hours, and then it goes down a bit from there. This is mind boggling to me. How many friggin dinasours were there anyway? With all of the jets in the air at any given time the amount of fuel being burned is more than my mind can grasp.

Regards,
 
It's not as bad as you think ...

For the heck of it, look at it this way ...

300,000 lbs jet fuel to move 250 people 6500 nm = 36.3 nm/gal/person

How many people get 41.8 sm/gal in their cars driving to work alone?

R/ Jim
Hoping to start on a -10 soon which gets 53 sm/gal/person (4 occupants) or 13 sm/gal/person (1 occupant) [200 sm/hr and 15 gal/hr burn]

P.S. I hope this math makes sense -- it's late here in KS.
 
Better than a Honda Civic

Bryan Wood said:
Not RV related, but interesting. Sunday my hanger neighbor dropped in to say hello and to kick tires. He is a retired 747-400 captain who flew the San Francisco to Sydney route at the time he retired. Always being curious about the fuel consumption of one of these planes I asked him how much fuel it takes to go one way to Australia.

"For the first hour the 400 burns an honest 25,000 lbs. of fuel per hour." As the 14 hour flight plays out the burn begins to go down slightly, but starts to become more noticeable around 10 hours out. By the last hour the burn is down around 18,000 lbs. per hour.

When I got home still not able to put into perspective fuel burns in pounds the calculator came to the rescue and translated it to 62 gallons per minute for approx. 10 hours, and then it goes down a bit from there. This is mind boggling to me. How many friggin dinasours were there anyway? With all of the jets in the air at any given time the amount of fuel being burned is more than my mind can grasp.

Regards,
Click to expand...
Jet fuel is closer to 6.6-6.8 lbs/gal so your 18,000 lbs/hr is equal to 44 gal/min.

Consider that the plane is moving about 490 kts, so that is .185111 nm/gal.

TIMES 380 passengers that is 70 nm - passenger/gal.

Of course this does not include the climb, which is much more burn. However the descent is done at idle to approach if you can work it out with ATC. Jets don't like to cruise down low, because spacific fuel consumption goes way up. The real killer is 140kt jet stream head winds and being Vectored all over creation to make an approach. However in cruise jets are very efficient.

This does not include the several tons of freight. So it is cheaper then your Honda Civic. :rolleyes:

The B767 is better in that if the B747-400 is burning 18,000lb/hr (4,500lb/hr per), the B767 is about 4,000lb/hr, a little slower cruise, and about 140 less passengers and less freight volumn, but about 95 nm-Pax/gal.

The real key, TWO engines not FOUR. That is why the made the B777, one big (efficient) twin.

Cheers George
 
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Fuel efficiency

fehdxl said:
How many people get 41.8 sm/gal in their cars driving to work alone?
Click to expand...
Very true, but how many people would drive from SF to Sydney? :)
 
A string of pearls

Yeah, I hear ya about the fuel. I used to fly the Asian route from Vancouver to Hong Kong and Beijing. 747 and 767. What would boggle my mind was that as we climbed up to cruise altitude and headed up the coast to Alaska, was a string of these behemoths, one every thousand feet and one every thirty miles or so, strung out, all going to Asia every day. It was getting so crowded that the tail fin could be shaking like a dog from the guy in front of you, only one thousand feet higher. The vortices will descend a full thousand feet and shake the crap out of the airplane behind. Sometimes we got to see the votices real close up and personal. They are like horizontal twisters and the vortexes are spinning so fast that they are blurred! Very impressive. We would offset our track to avoid this turb.

But yeah, when you think of all those 747s burning 24,000lbs an hour and you wonder how the world can deal with all that consumption when there is a string of those babies as far as the eye can see, plus!

Not to mention the weird clouds that are showing up nowadays. I've only seen them a few times, but there are some strange clouds, way up high that are radiant at night. Not aurora borealis either. I've flown up in the Arctic for five years and I know what those look like. These new clouds are higher than the stratosphere.

Cheers, Pete
 
Real gas hog

Pretty cool info.

If you want a real staggering number, try an F-4 Phantom in after burner, 4 gallons per second.
 
I worked evenings on the ramp at a relatively quiet Class C airport for a year or so. I think we had 5 or 6 5000 gal JetA trucks. On an average night each truck would get emptied twice. That's a quiet airport with maybe ten departures a night and half of those are usually turboprops. Multiply that by every quiet class C airport then add the busy ones and you'd still only have a fraction of what gets pumped through places like O'Hare and DFW every single day.
 
Staggering Numbers

The numbers are quite staggering, indeed. The economics involved in getting a plane off the ground and making a profit doing it is really quite amazing. I remember the days of flying with sometimes a dozen or fewer passengers in a plane. What a loss-leader those flights were. With the volatility of fuel prices, I can certainly understand why airlines are struggling a bit. The cost of getting one of these birds in the air and back down is enough to build our planes.

Hey Paul, how much fuel and what is the cost to get a shuttle flight into orbit?
 
That is why the made the B777, one big (efficient) twin.
Click to expand...

Another interesting bit of trivia:

You could take a 777 and place a 767 on its back & an MD-80 on each wing and the thing (aerodynamics aside) could take off and climb to 20,000 feet on ONE engine.
 
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Tom Maxwell said:
Hey Paul, how much fuel and what is the cost to get a shuttle flight into orbit?
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If I remember correctly the external fuel tank on the shuttle is something like 526,000 gallons and gets used up in less than 10 minutes. Thats like a bit more than an olympic sized swimming pool every minute - wonder how big a diameter those fuel lines are!

Then of course you have the solid rocket boosters to contend with...
 
If memory serves, the turbopumps on the Shuttle each generate about 60,000 HP. I bet the ones on the Saturn V's first stage engines were even bigger...those F-1 engines burned about 2.5 tons per second each.
 
Bryan Wood said:
"For the first hour the 400 burns an honest 25,000 lbs. of fuel per hour." As the 14 hour flight plays out the burn begins to go down slightly, but starts to become more noticable around 10 hours out. By the last hour the burn is down around 18,000 lbs. per hour.
Click to expand...

He must not have been in a hurry... I spent a year as a flight engineer on the B747-200, based in Guam. One night, headed home to Guam from Narita, the captain pushed 'em up a bit; we were cruising at .87 mach. Going home speed, of course. Fuel flow? Right around 29,000 lbs/hr. Ouch. Made for a quick trip home though!
 
Baja_Traveler said:
wonder how big a diameter those fuel lines are!

..
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The Liquid Hydrogen and Oxygen from the External Tank to the Orbiter flow through 17" diameter disconnects....

Paul
 
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