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 !