cosmofly
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747-8 Fuel Burn

Wed Feb 10, 2010 1:46 am

First flight pilots said the take off weight is 630,000lb of which 130,000lb is fuel. Test flight is almost 4hr and pilots said they can fly another 8hr before landing. Granted that it was only flying at 200 knots, is there enough info to project the actual fuel burn of the 748?

http://www.aviationweek.com/aw/gener...el=comm&id=news/Land020810.xml
 
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Stitch
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 1:50 am

LH's latest projections show 3.5 liters per 100km, .1 liters more than the projections for their A380-800s and .7 liters better than their 747-400s.
 
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Web500sjc
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 4:22 am

Why do they load up that much fuel, and what is the Maximum landing whieght of that bird! or did they just dump the rest
of the fuel before landing
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OldAeroGuy
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 5:55 am

Quoting cosmofly (Thread starter):
First flight pilots said the take off weight is 630,000lb of which 130,000lb is fuel.
Quoting web500sjc (Reply 2):
Why do they load up that much fuel, and what is the Maximum landing whieght of that bird!

The Max Landing Weight of the 747-8F is 757,000 lb.

http://www.boeing.com/commercial/airports/acaps/7478sec2.pdf

The airplane was below MLW at takeoff. No fuel was dumped prior to landing.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
OldAeroGuy
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 5:57 am

Quoting cosmofly (Thread starter):
Granted that it was only flying at 200 knots, is there enough info to project the actual fuel burn of the 748?

No, cruise fuel mileage will not be tested until basic airworthiness has been established.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
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747classic
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 9:51 am

Quoting OldAeroGuy (Reply 4):
No, cruise fuel mileage will not be tested until basic airworthiness has been established.

Correct, the exact fuel mileage will be verified on N5017Q (RC521), the second 747-8F test aircraft.

"The second 747-8F (RC521) will join the flight test program as soon as RC501's work confirms the high- and low-speed configuration around mid-March. Painted identically to the first aircraft for the test program, RC521's principal task will be proving the General Electric GEnx-2B67 engines and fuel efficiency of the model measured during NAMS (nautical air miles) tests."

For further detailed 747-8F certification schedule :
http://www.aviationweek.com/aw/gener...=comm&id=news/Flight020410.xml
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Fabo
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 3:30 pm

Quoting Stitch (Reply 1):
LH's latest projections show 3.5 liters per 100km, .1 liters more than the projections for their A380-800s and .7 liters better than their 747-400s.

What configurations do they compare with 744 and 748?
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alwaysontherun
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 7:01 pm

Quoting web500sjc (Reply 2):
or did they just dump the rest
of the fuel before landing

I am no expert, but I do not think you can "plan" to dump fuel before take off, as part of your operation.
Environmental organizations and local government may have something to say about that!
That is pretty much an emergency procedure, not something you do just for the sake of it.

What I would like to know, how do they test the fuel dumping facility on a new aircraft?
On the apron?

### "I am always on the Run"###
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Stitch
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RE: 747-8 Fuel Burn

Wed Feb 10, 2010 8:29 pm

Quoting Fabo (Reply 6):
What configurations do they compare with 744 and 748?

526 for the A388, 420 for the 748 and 330 for the 744.
 
tdscanuck
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RE: 747-8 Fuel Burn

Thu Feb 11, 2010 5:14 am

Quoting web500sjc (Reply 2):
Why do they load up that much fuel

You want early flights to be mid-CG and mid-weight...you want to be right in the heart of the flight envelope since at the edges there be dragons. The easiest way to move CG and weight around is fuel load.

Quoting alwaysontherun (Reply 7):
I am no expert, but I do not think you can "plan" to dump fuel before take off, as part of your operation.

You can. Its done routinely on test flights.

Quoting alwaysontherun (Reply 7):
What I would like to know, how do they test the fuel dumping facility on a new aircraft?

Takeoff, get some altitude, turn on fuel jettison system.

Quoting alwaysontherun (Reply 7):
On the apron?

Now *that* would annoy the airport. This type of testing can be done in a fuel dock if you've got hoses to catch everything coming out of the jettison pipes, but that's a pain. It's a lot easier to just fly it.

Tom.
 
KELPkid
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RE: 747-8 Fuel Burn

Thu Feb 11, 2010 7:01 am

Quoting alwaysontherun (Reply 7):
Environmental organizations and local government may have something to say about that!
That is pretty much an emergency procedure, not something you do just for the sake of it.

If it's done at altitude, the fuel atomizes and evaporates before it hits the ground...okay, it might cause a localized area of smog on a sunny day  

Wasteful? Yes. But it's gotta be tested before someone has to do it in reality...and when it's needed in real life, it might save a life or even an airframe (a poorly-executed overweight landing could be the end of an airframe).
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alwaysontherun
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RE: 747-8 Fuel Burn

Thu Feb 11, 2010 2:54 pm

Quoting tdscanuck (Reply 9):
You can. Its done routinely on test flights.

Without any permission from local authorities or anything like that?
Now that really surprises me!
I work in an industry where every drop counts, literally!
You drop as much as 1 liter of hydrocarbon in the water and you may end up in court, depending on circumstances obviously!

That is interesting. I thought they would test that on the ground.

Quoting tdscanuck (Reply 9):
This type of testing can be done in a fuel dock if you've got hoses to catch everything coming out of the jettison pipes

Something like that is what I had in mind.

Just to confirm this point: a test pilot can open up "the valves" anywhere, as long as it is at sufficient altitude.

Quoting KELPkid (Reply 10):
okay, it might cause a localized area of smog on a sunny day

Is that all?

That is the good thing about this site, so much to learn!

### "I am always on the Run"###
"Failure is not an option, it comes standard in any Windows product" - an anonymous MAC owner.
 
tdscanuck
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RE: 747-8 Fuel Burn

Fri Feb 12, 2010 2:01 am

Quoting alwaysontherun (Reply 11):
Quoting tdscanuck (Reply 9):
You can. Its done routinely on test flights.

Without any permission from local authorities or anything like that?
Now that really surprises me!

As far as I know, yes. It's possible that the companies that do it have discharge permits to specifically cover this, but I've never heard of that before. Keep in mind that you're not dumping liquid hydrocarbons on the ground or water...it all evaporates before it gets to the ground. All jets dump some hydrocarbon vapour due to incomplete combustion, so it's just a matter of degrees.

Quoting alwaysontherun (Reply 11):
Just to confirm this point: a test pilot can open up "the valves" anywhere, as long as it is at sufficient altitude.

Yes but, as mentioned above, there may be some kind of blanket preauthorization paperwork that I don't know about. I do know that you can do this on tests without getting specific permission for each individual test.

Tom.
 
alwaysontherun
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RE: 747-8 Fuel Burn

Sun Feb 14, 2010 1:55 pm

Thanks Thomas,

you are a good man.

### "I am always on the Run"###
"Failure is not an option, it comes standard in any Windows product" - an anonymous MAC owner.

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