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Lufthansa 747-8 Fuel Burn  
User currently offlinetrex8 From United States of America, joined Nov 2002, 4770 posts, RR: 14
Posted (2 years 3 months 6 days 3 hours ago) and read 12975 times:
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I can't find it on line but in the June 18 paper edition of AWST, pg 46 there is an article on the first 747-8 revenue flight. Fuel burn was 0.3% less than predicted and 3% less than LH expected for a 744 flying the same mission. There was a thread a few weeks ago , which unfortunately I can't seem to find now. IIRC people were saying there were reports the 747-8 was burning 10% less fuel than a 744. Even with the anticipated 2014 improvements in weight and engine PIP etc, is it really realistic to see a 10% improvement if LH are only seeing 3% with their first plane?

36 replies: All unread, showing first 25:
 
User currently onlineStitch From United States of America, joined Jul 2005, 31012 posts, RR: 86
Reply 1, posted (2 years 3 months 6 days 3 hours ago) and read 12915 times:
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Quoting trex8 (Thread starter):
IIRC people were saying there were reports the 747-8 was burning 10% less fuel than a 744

Projected fuel burn savings are between 10 and 15%.

The following was reported for the inaugural FRA-IAD flight (LH416) on 01 June.

378t TOW
296t LW
50t Payload (313 passengers and 20 crew)
80t Trip Fuel Burn
7h58m Trip Time

Midway through the flight, while cruising at 36,000ft, Capt Boje reported a combined fuel flow of 9.6t/h (at M0.843) from the four General Electric GEnx engines, with a ground speed of 479kt (886km/h) and a 20kt headwind.


User currently offlineSEPilot From United States of America, joined Dec 2006, 6914 posts, RR: 46
Reply 2, posted (2 years 3 months 6 days 3 hours ago) and read 12858 times:

Quoting Stitch (Reply 1):

Projected fuel burn savings are between 10 and 15%.

Is this per trip or per seat?



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlinevin2basketball From United States of America, joined Dec 2009, 317 posts, RR: 0
Reply 3, posted (2 years 3 months 6 days 3 hours ago) and read 12814 times:

Quoting trex8 (Thread starter):
I can't find it on line but in the June 18 paper edition of AWST, pg 46 there is an article on the first 747-8 revenue flight. Fuel burn was 0.3% less than predicted and 3% less than LH expected for a 744 flying the same mission. There was a thread a few weeks ago , which unfortunately I can't seem to find now. IIRC people were saying there were reports the 747-8 was burning 10% less fuel than a 744. Even with the anticipated 2014 improvements in weight and engine PIP etc, is it really realistic to see a 10% improvement if LH are only seeing 3% with their first plane?

Fuel burn per seat can be easily 10-12% lower on 748i vs. 747-400.

Let's take nominal fuel burn as 3% less.

Then Lufthansa's 744s seat on avg ~350 seats (3 configs @ 322, 353, and 370 seats, I averaged out the 3), so that's a 10.3% advantage for the 748 in # of seats. That works out to a 12.5% advantage in fuel burn per sear for the 747-8i


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 4, posted (2 years 3 months 6 days 3 hours ago) and read 12700 times:

Quoting vin2basketball (Reply 3):
Then Lufthansa's 744s seat on avg ~350 seats (3 configs @ 322, 353, and 370 seats, I averaged out the 3), so that's a 10.3% advantage for the 748 in # of seats. That works out to a 12.5% advantage in fuel burn per sear for the 747-8i

Using the 323 seat 744 configuration as a base, which is closer to 748 configuration in terms of seat pitch and , premium to economy seat distribution, 748 has about 12.4% more seats. Assuming 3% lower trip fuel burn, early LH B748 is about 15% lower fuel burn per seat than its B744.

Does anyone have cabin area numbers for 744 and 748?


User currently onlineStitch From United States of America, joined Jul 2005, 31012 posts, RR: 86
Reply 5, posted (2 years 3 months 6 days 3 hours ago) and read 12670 times:
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Quoting LAXDESI (Reply 4):
Does anyone have cabin area numbers for 744 and 748?

B747-400: 372.0 sq meters (per Widebodyphotog)
B747-8: 444.6 sq meters (per Boeing)


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 6, posted (2 years 3 months 6 days 2 hours ago) and read 12576 times:

Quoting Stitch (Reply 5):
B747-400: 372.0 sq meters (per Widebodyphotog)
B747-8: 444.6 sq meters (per Boeing)

Thanks. Going by above numbers, B748's cabin is about 19.5% larger. It seems that LH B748(362 seats) is not as densely configured as its B744(322 seats), as it has only about 12.5% more seats.


User currently onlineStitch From United States of America, joined Jul 2005, 31012 posts, RR: 86
Reply 7, posted (2 years 3 months 6 days 2 hours ago) and read 12432 times:
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Quoting LAXDESI (Reply 6):
Going by above numbers, B748's cabin is about 19.5% larger. It seems that LH B748(362 seats) is not as densely configured as its B744(322 seats), as it has only about 12.5% more seats.

Which roughly tracks with LH's fuel burn analysis of 3.8 liters per 100 passenger kilometers on the 362-seat 747-8 compared to 4.2 liters per 100 passenger kilometers for the 344-seat 747-400 - a 10% reduction.

[Edited 2012-06-19 17:02:58]

User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 8, posted (2 years 3 months 6 days 2 hours ago) and read 12281 times:

Quoting Stitch (Reply 7):
The 747-8 is 386 seats: 8F / 80C / 298Y

Seatguru must be in error as it shows 8F/92J/262Y.

Quoting Stitch (Reply 7):
The closest 747-400 config would be the 322-seat version at 8F / 80C / 234Y, so the difference would be 27% more seats, all of them Economy.

Thanks. If trip fuel burn is 3% less as per OP, then the early LH B748 has 30% lower seat fuel burn than B744.

Need more confirmation on trip fuel burn.


User currently offlineAviaco From Germany, joined May 2012, 34 posts, RR: 0
Reply 9, posted (2 years 3 months 6 days 2 hours ago) and read 12159 times:

8F/92J/262Y is correct.

User currently offlineikramerica From United States of America, joined May 2005, 21532 posts, RR: 60
Reply 10, posted (2 years 3 months 6 days 2 hours ago) and read 12130 times:

While it's not out of line to think a new design can fly the same mission with 12-20% more seats and using less total fuel, it's a testament to the engineers at Boeing and GE that the 2nd major overhaul of a 40+ year old frame can achieve the same outcome.


Of all the things to worry about... the Wookie has no pants.
User currently onlineStitch From United States of America, joined Jul 2005, 31012 posts, RR: 86
Reply 11, posted (2 years 3 months 6 days 2 hours ago) and read 12049 times:
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Quoting LAXDESI (Reply 8):
Seatguru must be in error as it shows 8F/92J/262Y.

SeatGuru is correct. Wikipedia is not (until I edit the page, at least).


User currently offlinetrex8 From United States of America, joined Nov 2002, 4770 posts, RR: 14
Reply 12, posted (2 years 3 months 6 days 1 hour ago) and read 11914 times:
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Got it, so on a per trip basis it may be 3% but on a per seat its 10%+. Whats the per seat fuel burn for a 77W vs 744?

User currently offlineRoseflyer From United States of America, joined Feb 2004, 9652 posts, RR: 52
Reply 13, posted (2 years 3 months 6 days 1 hour ago) and read 11872 times:

I think the premium heavy configuration of the 747-8 makes it hard to compare. The 747-8 has the same number of first and business class seats as the A380 in LH configuration. That really skews the numbers in the fuel burn per seat. LH also has multiple 747-400 configurations. If comparing trip fuel burn, a good guess can be made, but it is still really hard to compare and know what the assumptions are. This is basically true whenever comparing models. In general the 747-8F and 747-8I have very similar fuel burn on a trip basis than their 747-400 counterparts, but the -8s have higher payload to make up for it.


If you have never designed an airplane part before, let the real designers do the work!
User currently offlinenycdave From United States of America, joined Aug 2010, 547 posts, RR: 1
Reply 14, posted (2 years 3 months 6 days ago) and read 11658 times:

Quoting LAXDESI (Reply 6):

Quoting Stitch (Reply 5):
B747-400: 372.0 sq meters (per Widebodyphotog)
B747-8: 444.6 sq meters (per Boeing)

Thanks. Going by above numbers, B748's cabin is about 19.5% larger. It seems that LH B748(362 seats) is not as densely configured as its B744(322 seats), as it has only about 12.5% more seats.

So, in terms of fuel relative to floor space... the early 748 is doing almost an 18% improvement over the 744, meaning about that amount improvement per seat, if outfitted at the same density. Easy to see the later line numbers come out over 20%. Very impressive improvement, Boeing (and LH) should be quite happy.


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 15, posted (2 years 3 months 5 days 22 hours ago) and read 11358 times:

Quoting nycdave (Reply 14):
So, in terms of fuel relative to floor space... the early 748 is doing almost an 18% improvement over the 744, meaning about that amount improvement per seat, if outfitted at the same density. Easy to see the later line numbers come out over 20%. Very impressive improvement, Boeing (and LH) should be quite happy.

The LH 748 is actually doing 22.5% better than 744 on fuel per cabin space metric(19.5% +3%). Impressive.

A "mature" B748 should be able to achieve 25%+ lower fuel burn per seat, if the 3% lower trip fuel number in OP is correct.

The spec. MTOW of 748 is about 13% higher than that of 744. A 3% lower trip fuel burn for 748 seems plausible.


User currently offlineseabosdca From United States of America, joined Sep 2007, 5481 posts, RR: 6
Reply 16, posted (2 years 3 months 5 days 21 hours ago) and read 11325 times:

Quoting LAXDESI (Reply 15):
A "mature" B748 should be able to achieve 25%+ lower fuel burn per seat, if the 3% lower trip fuel number in OP is correct.

And yet it still can't compete with the A380. We've come a long way in 20 years!


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 17, posted (2 years 3 months 5 days 20 hours ago) and read 11283 times:

Quoting seabosdca (Reply 16):
Quoting LAXDESI (Reply 15):A "mature" B748 should be able to achieve 25%+ lower fuel burn per seat, if the 3% lower trip fuel number in OP is correct.
And yet it still can't compete with the A380. We've come a long way in 20 years!

On many routes, where A380 is too much capacity, B748 is likely to be more profitable as it has 20 % lower trip fuel burn on a 6,000 nm mission(see example below). LH has stated that it sees a role for both B748 and A380, and one is more profitable than the other depending on the route..

An old thread where I compared the A388 to B748.
A388 Versus B748 Economic Analysis (by LAXDESI Jul 26 2008 in Tech Ops)

Quoting LAXDESI (Reply 18):
For a 6,000 nm trip,

A388 burns 53,007 gallons, carries 90,469 lbs. cargo, GSM .0168, GTM 0.0968
B748 burns 42,397 gallons, carries 84,050 lbs. cargo, GSM .0174, GTM 0.0919

A388 burns additional 10,610 gallons at a cost of $42,000
A388 earns additional $84,000 (120 seats X 70% LF X $1,000) in seat revenues.
A388 earns additional $5,000 (6,419 lbs. X 50% LF X $1.5) in cargo revenue.

The net trip advantage to A388 is $47,000--about $17 million annually.


User currently offlinesweair From Sweden, joined Nov 2011, 1824 posts, RR: 0
Reply 18, posted (2 years 3 months 5 days 17 hours ago) and read 11183 times:

in 2014 LH said they will get the mature frame, how much weight will be taken out and will the MTOW stay as it is? The engines should be near spec with the PIP as well.

I think the 748 will be a very good aircraft if you have the need for belly cargo and not 100% filled cabin. The freighter is said to fly 134t as far as the 744 freighter can fly 124t?


User currently offlinenomadd22 From United States of America, joined Feb 2008, 1867 posts, RR: 0
Reply 19, posted (2 years 3 months 5 days 10 hours ago) and read 10978 times:

Quoting LAXDESI (Reply 17):

Quoting LAXDESI (Reply 18):
For a 6,000 nm trip,

A388 burns 53,007 gallons, carries 90,469 lbs. cargo, GSM .0168, GTM 0.0968
B748 burns 42,397 gallons, carries 84,050 lbs. cargo, GSM .0174, GTM 0.0919

A388 burns additional 10,610 gallons at a cost of $42,000
A388 earns additional $84,000 (120 seats X 70% LF X $1,000) in seat revenues.
A388 earns additional $5,000 (6,419 lbs. X 50% LF X $1.5) in cargo revenue.

The net trip advantage to A388 is $47,000--about $17 million annually.

I'm not sure what that's suppose to prove. It's just saying that more passengers and more cargo make you more money. That would be true no matter what planes you were comparing. As far as fuel use, the 748 is a clear winner in fuel used per cargo and about even per passenger.



Andy Goetsch
User currently offlineWingedMigrator From United States of America, joined Oct 2005, 2214 posts, RR: 56
Reply 20, posted (2 years 3 months 5 days 10 hours ago) and read 10961 times:

Quoting LAXDESI (Reply 15):
The LH 748 is actually doing 22.5% better than 744 on fuel per cabin space metric(19.5% +3%).

Careful with percentages! If the 748 is 1.195 times bigger and uses 0.97 times the fuel, then the 744 has 1.232 - 1.0 = 23% higher fuel burn per seat than the 748, but the 748 has 1.0 - (1/1.232) = 1.0 - 0.812 = 18.8% lower fuel burn per seat than the 744. So the LH 748 is doing 18.8% better, not 22.5% better than the 744.

Linear approximations are only valid for small percentages, which I suppose is a testament to the step change in performance that the 748 brings.


User currently onlineStitch From United States of America, joined Jul 2005, 31012 posts, RR: 86
Reply 21, posted (2 years 3 months 5 days 9 hours ago) and read 10956 times:
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Quoting seabosdca (Reply 16):
And yet it still can't compete with the A380. We've come a long way in 20 years!

It would be a sad commentary on Airbus if the A380-800 wasn't better than the 747-8 considering they started clean-sheet and with a larger airframe.



Quoting sweair (Reply 18):
in 2014 LH said they will get the mature frame, how much weight will be taken out and will the MTOW stay as it is?

Estimates are Boeing is working to remove around 2.5 metric tons of weight (so about 5000 pounds). Once the plane is at design weight, fuel burn should improve between 0.5 and 1.0 percent.


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 22, posted (2 years 3 months 5 days 8 hours ago) and read 10882 times:

Quoting WingedMigrator (Reply 20):
Careful with percentages! If the 748 is 1.195 times bigger and uses 0.97 times the fuel, then the 744 has 1.232 - 1.0 = 23% higher fuel burn per seat than the 748, but the 748 has 1.0 - (1/1.232) = 1.0 - 0.812 = 18.8% lower fuel burn per seat than the 744. So the LH 748 is doing 18.8% better, not 22.5% better than the 744.

You are right, it is 18.8% better. Thanks for catching my mistake. Hopefully, a mature B748 delivers about 20% lower seat fuel burn.

Quoting nomadd22 (Reply 19):
I'm not sure what that's suppose to prove. It's just saying that more passengers and more cargo make you more money. That would be true no matter what planes you were comparing. As far as fuel use, the 748 is a clear winner in fuel used per cargo and about even per passenger.

One is better over the other depending on the route.

A380 is better than B748 where A380 is not too much capacity. LH is deploying B748 to IAD, which suggests that currently A380 may be too much capacity for IAD.


User currently offlinesweair From Sweden, joined Nov 2011, 1824 posts, RR: 0
Reply 23, posted (2 years 3 months 5 days 5 hours ago) and read 10780 times:

If Boeing manages to get weight out of the frame and keep the MTOW this is all "free" payload right? 3-4tons more payload cant be that bad? If the current 748 can take on 4t more fuel, what will that do for range?

User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 24, posted (2 years 3 months 4 days 21 hours ago) and read 10605 times:

LH configuration for B748 and A388:

B748................8F/92J/262Y
A388................8F/98J/420Y

A388 has an additional 6J and 158Y seats over B748, for a total of 164 seats, which is a lot more than 120 seats that I assumed in my example in reply # 17.

Using additional 164 seats(and not 120) in that example should change the annual operating advantage of A388 over B748 to nearly $28 million(from $17 million).

Does anyone have cabin area numbers for A388?


25 zeke : Keep in mind the age of the 744 and 748, a brand new 744 would probably do over 3% better than a 15 year old 744 airframe. That has been the industry
26 Post contains images wilco737 : Almost, it is IAH, Houston which starts August 1st with A388. wilco737
27 Stitch : 600m2 per Airbus
28 WingedMigrator : I have 552 m2 of usable floor area, a figure that I think originally came from widebodyphotog. I was able to verify this to within a couple of percen
29 LAXDESI : Going by the above numbers, A388 has 35% more cabin area. Widebody has 427 sq meter for B748. Going by the above numbers, A388 has 29% more usable ar
30 sunrisevalley : The 499k airspeed, is this typical cruise speed? I find this thing about fuel burn per seat mile to be rather incomplete . I much prefer fuel burn pe
31 zeke : M0.843 at FL360 is a TAS of 484 kt, something does not look right with the numbers. 499 kts at FL360 is M0.87, the quoted speeds make more sense for
32 sweair : What would 5000 pounds less structural weight do for range? If that would be fuel loaded?
33 zeke : I would guess around 100 nm.
34 Post contains images sunrisevalley : Checking this back from TOW, assuming the burn was ~87% of the fuel load ( this is what it was for the A380 example in reply 30) then fuel load was 9
35 Post contains images Stitch : LH's premium cabin product should be significantly heavier than what Boeing uses in their OEM configuration so even with 90 less Economy seats, I wou
36 sunrisevalley : This seems likely. Compared to the A380 OEW spread from 292 to 299t and assuming LH is at the high end of the spread , then add ~7t , then add weight
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