747-8 fuel burn?
 

Hi there,

I have a question for those who is on the 747-8. What is the fuel consumption per hour on the new 747-8?

Now that the 747-8s are in service, it would be interesting in the comparison to the a380.

Well Dan Buster, you better give me the answer I seek to avoid this thread becoming one of those threads you dreaded about.

No? Oh Joy!

The burn seems to be very similar to a -400, but the -8F does that 50 tons heavier.

He asked for the burn, not burn at respective max weights. What the hell are you thinking making a statement like that? :ugh:

Trying to fuel another A vs B discussion? :=

... but A vs B threads are so much fun.

I agree with the above statement that the 747-8F burns roughly the same as the -400F in cruise (and yes, with about 16% more volume, 20% more payload, and about 50T more total weight). However, I have noticed significant reductions in fuel burn during the T/O and climb phases of flight. This makes sense as a bigger fan should be more efficient at lower altitudes.

I think the relevant data comes from Boeing and Lufthansa. The per seat / tonne economics on the -8 are roughly the same as the 777-300ER / 777F. As per Lufthansa (and their respective seating configurations), the A380 has about a 3% per seat cost advantage over the -8I. One could further deduce that the same advantage applies vs the 777-300ER. I would be curious to hear from someone at Singapore as to their observed difference. Also, I am curious how much belly volume / payload is dedicated to cargo on a full, Euro-bound A380.

Thanks Cxorcist. A rough figure would be about 10-12 tonnes per hour depending on weight?

Yeah, that's about right. 12-10-8T/hour for heavy, medium, and lite weights (450, 375, 300T) respectively. Engines should get better over time with PiP upgrades. Wing is an amazing lift generator. The biggest downside is that the -8 gained 30T of weight over the -400. I hoped for less, but Boeing had to add lots of extra structural support for the longer fuselage. Airbus had similar struggles with the A340-600. I understand the wing and engines weigh quite a bit more than the -400 as well. The -8 should get lighter over time and is supposed to meet originally published specs by 2015.

cxorsist
 

I have found that to be true of most types I have flown!!

:)

Is this more delay?
 

cxorsist Quote:- "The -8 should get lighter over time and is supposed to meet originally published specs by 2015."

So, if the -8 meets its design specification in 2015 how many years late will that be?

It seems that the A350 still has a few years to play with - and probably will.
:hmm:

China Flyer,

This was a reference to the fact that the wing lifts 50T (12.5%) more than the -400 at about the same speeds and similar thrust rating from the engines. What other stretched airliner does the same? I cannot think of a single one. Most keep the same wing and dial up the speeds and thrust. Just an observation.

...and the same retards showing up on this airbus vs. Boeing thread. Seriously, you don't have better things to do?

I would rather be doing this than what you are doing, Cumguzzler. I sure hope you are a woman!

Oh how I love the B v A banter.

Cxorcist, picking up my EK timetable and looking at page 322 and it tells me the Uglybus carries 8 (eight) tonnes of cargo, don't choke on your beer!!!!

The Boeing 777-300ER carries 23 tonnes!!!

So with wing cracks and no payload capability why bother with the heap of crap?

747-8, longer fuselage and different wing
 

cxorcist Quote:- "This was a reference to the fact that the wing lifts 50T (12.5%) more than the -400 at about the same speeds and similar thrust rating from the engines. What other stretched airliner does the same? I cannot think of a single one. Most keep the same wing and dial up the speeds and thrust. Just an observation."

As I understand it, the 747-8 has a redesigned wing which, although similar to that of the -400, is different. The wing span of the -8 is 4.1m longer than that of a -400 and the wing section is deeper. Additionally the flaps on the -8 are no longer triple slotted but are single slot outboard and double slotted inboard.

It should, therefore, not come as a surprise that this new wing can lift a greater weight.

If Boeing had tried to mate a -8 fuselage with the wing of a -400 they would have been as successful as the McDonnell Douglas with the MD11 which was more or less what you described - keeping the same wing and dial up the speeds and thrust. Perhaps, having bought McDonnell Douglas, Boeing were forewarned of this folly.

Not withstanding the above, the -8 is quite impressive although orders for passenger variants are not strong - too many engines for this day and age?

FERetd,

I agree with your post... except the MD-11 did have a redesigned wing. It is wider than the DC-10's, but it lost chord and camber. Ultimately, it was too small to generate sufficient lift despite the split winglet design which seems to be back in style on the 737 Max. The MD-11's engines and speeds had to be dialed up hurting both runway and cruise performance. In the end, a bit too bastardized to be really successful, especially as the 777 came along.

It will be interesting to see if a new 4 engine airplane can be successful in this day and age as anything more than a freighter. It seems that it might be in part determined by how soon Boeing produces the 777X, which will be largely determined by how extensive the delays are on the A350 and how much engineering is required for the 787-10. Time will tell...

MD11 wing
 

Hello cxorcist, thank you for your response.

I cannot be too specific about the MD11 wing. The wing span is +/- 5 feet longer than the DC10-30 or -40, but that may be because of the winglets/training wheels.

I believe that there was some redesigning of the wing trailing edge and wing to fuselage fairings but am not sure if this includes a "new" wing.

I am reminded of a chat that I had with an American MD11 skip at the Flehlappe, in Maintz some years ago. He said that the MD11 was a good aeroplne (airplane?) except that it was a 600,000Lb. aeroplane with a 500,000Lb. wing - give or take a few Lbs. His description, I think, corroborates your own views on stretched aircraft.

Regarding the 747-8 and indeed the A380, I think that it is going to take a good salesman to sell a four-engined aircraft in present times.

Take care!

The Flehlappe is still in Maintz except i think the name has changed.
Very popular with air crew

MD11 wing
 

The big problem of the MD 11 was, that there was no money left to design a new wing. Thus, especially in the freighter version with much higher TO and LDG weights (286/223to) the cL was to small so much higher speeds had to be used. Minimum clean at MLAW was about 245. V2 MTOW 180. This again required always RWYs with minimum 3000m.

The stabiliser though was redesigned, and smaller than the DC 10's. This again required that Douglas had to develop the famous LSAS (Longitudinal Stabilisation Augmentation System). This gave the MD-11 incredible stability during turbulence. You could stall the airplane, take your hands of controls and it would recover totally without pilot inputs, just by automated thrust and elevator movements. No other commercial airliner ever could do that.

The reason the MD11 failed was the laking of of new wing. Especially in a time when fuel consumption was critical.

The MD11F has a FF of 7200kg/h at MTOW. The A340-600 has the same FF. Only weighting 386to!

"The Flehlappe is still in Maintz except i think the name has changed.
Very popular with air crew "

Yeah, changed to Mainz.:E

Cripes, nothing changed at CX. The question was a simple "what is the fuel burn per hour". Pages of typical CX BS but still no answer. Well, I stopped reading the mindless drivel after a few responses so the answer might be there. Now we are talking about MD-11 split winglets. Good grief. Stay focused girls......here comes a CB !

Ah, the MD-11... Probably still one of, if not the best designed cockpit around. The automation and flight guidance is definitely kicking the pants off the Airbus WBs, I am flying right now.
If only MDD had more resources to build a better wing. Airbus could have rolled their A340 after the maiden flight straight into the museum.

Also now of some FedEx guys, who uttered their disappointment about systems and flight guidance when they did their 777 conversion. Answer of the instructor was: "yes, we know.... But at least we give you a bigger wing" :p

OK, I'll give it to you

450T 13400kg/hr
280T 8400kg/hr
210T 6000kg/hr

Basic wt around 190T

Hooooray ! Backspace, thanks V much. 27 replies to get there. Now I can compare my fuel burn, feed in loads, weight, revenue discussion and maybe figure how my lot continue to make huge losses.Might have to recommend Md-11's.

whilst we are at it, how about the A380 figures for the same weight? Or are airbus lovers just as embarrassed too by the not too frugal figures?

A380

569t 13.3t/hr first lot; 12.7t/hr new batch
450t 11.7t/hr first lot; 11t/hr new batch
390t 11.0t/hr first lot; 10.5t/he new batch

Seems flying a few miles higher than the 747 saves fuel...who would have guessed?

MZFW 366t. DOW 297t. Mtow 569t or 573t depending on config.

Not embarrassed at all. Remembering we have 150 more pax on board than a LF 748 or 200 more than a CX 773er.

The Don

That shut them up!!:D

Kasompe,
MZFW-DOW=69T
this is not something to gloat about.

Don, (I am assuming you reside in the desert) what is the longest route that EK do in the 380 and any figures available for that. The numbers that count are kg fuel/ton payload, the rest is smoke and mirrors.

Yeah, that payload is a joke for an aircraft that size. CX 777-300ERs will carry 55T+ with full pax and 20-25T in the bellies. Yes, I have seen this on HKG-LAX (ZFW 225T+) on several occasions.

The thing they don't tell you about the A380 is that it is not the MZFW that is limiting, it's actually a lack of volume in the bellies to get anything more than all the bags down there. That's why CX won't buy it, or so I'm told. Maybe this particular director thought I was a spy for Airbus.:eek:

I should point out that the figures for the 748 are for the freighter, not sure about the -8I. I suspect the basic wt is less.

-400 pax is about 20T heavier than production freighter

CXorist,

Our 777 is limited to carrying just 40t from Oz east coast to the sandpit (14hrish). the 380 carries the full ZFW. So if we are carrying the full ZFW can you please explain how it is limited? This is why EK is swapping the ULR flights from the 777 to the 380. If you know something that EK flight ops don't, perhaps you should contact them and let them know.

The Don

Don,

So how much of the 69T payload is freight? My understanding is that with 500 pax and all their bags, there is not any room (volumetrically) left for cargo. Is this incorrect?

I can't speak to 777 ops for EK, only for CX. I have seen ZFW of 230T+ HKG to LAX. This exceeds 55T payload with 102T burn and a 12 hour flight time. The flight could have flown at least another 1.5 hours or carried another 7T+ payload. How much is the EK A380 burning on a 12 hour flight at MZFW?

Cheers!

CX,
The 345 carried 45t outa oz every day for 100kg per less than the 773. But it had 100 seats less than the 773. So the 773, carrying 5t less, burning more fuel, carrying less frieght but more pax makes more money.

How does that work?

the Don

Let's face CXorcist CX have no option but to buy the 380, even the argument regarding the limited payload capacity doesn't stack up anymore! Here we have EK pilots telling us so and I'm pretty sure they would know! But, but, but the 380 is the wrong aircraft for Cathay I hear everyone cry, I bet people would have said that about the 400 before it started into service and look how that turned out. :eek:

Don,

Just answer the questions?

I have no idea what you are talking about wrt the A345. The market has spoken on that airplane, and it was sentenced to death along with the A346.

If you are implying that passengers are always more profitable than cargo, then I simply disagree, especially if you are referring to Y class. But maybe hauling back-packers is EK's business model, if so, good for EK A380s. CX's business model is hauling premium passengers and cargo. Y class is only there to provide an aft CG for aircraft efficiency (sarcasm).

I would say hauling premium pax is every airlines business model, CX does not stand out as being particularly special in any regard.

330,

Some more than others as a portion of revenues:ok:

Todays Brisbane flight (777) delayed an hour to off load cargo and wait for the longer runway. The Sydney and Melbourne (380) leave ontime with no dramas.

Seems there could be a good reason for the 748 and 380 as these 777 seem a bit precious. :E

The don.

Don,

Save your breath. This will go straight over cxorcist's head as he can see nothing negative about Boeing or positive about Airbus. He's got voluntary selective vision. You can cure a sick person but never cure one who pretends to be sick.

OK, copy. You're not going to answer any questions. Just don't jump on here and act as if you're an expert just because you fly the A380. They are simple questions in search of simple answers. Wouldn't want to piz you off...

FWIW, I agree that quads have a place in the market. It's just a much smaller place than it used to be due to high fuel prices and low economic confidence. I have no doubt CX would buy 2 dozen 747-8Is if they were convinced the global economy weren't going to take a big dump in the next few years.

It's tough for an airline as proud as CX to point to a 777 and call it the Swire's flagship. No doubt, the premium passengers are much better served when they turn left into an exclusive area upon stepping onboard. The 777 leaves much to be desired in terms of service delivery, but that's the world we live in right now.

If EK can fly a hundred A380s all over the globe and make money, good for them. But I think CX has run the numbers many times, and the result is the same each time... Big airplane=big risk. No cargo=less revenue. It's a pretty toxic combination for the bean counters, no matter how much pilots love them.