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AW&ST: B747-8F - Better Than Expected Fuelburn  
User currently offlineOyKIE From Norway, joined Jan 2006, 2717 posts, RR: 4
Posted (5 years 7 months 3 weeks 6 days 4 hours ago) and read 9565 times:

In this week’s Aviation Week there is an article talking about the 748i that is being pushed back. There are some interesting comments concerning the program. I found them so interesting that I believe it qualifies for a thread of its own.
Here are some quotes from the article November 24. 2008. Page 24
[qoute] The issues began in 2007 when test revealed higher than expected loads on the aircraft’s new supercritical wing, particularly at low speeds. Although the wing is all-new, its planform is the same as the -400’s and the configuration at the root is the same. “Putting that additional load through the same shape required the biggest amount of strengthening” [/quote]

Quote:
The loads on the wing at lower speed also shifted the center of gravity further aft, requiring a higher balancing tail load.



Quote:
The other focus for Boeing is on “essentially getting the performance of the aircraft to what the customers need.



Quote:
“We’re an 8000 nautical mile aircraft and this is where we need to be. The A380 coming out of the gate is not, so we have the ability to beat that.



Quote:
Additional weight-saving “opportunities” are being defined for aircraft beyond the first -8F. These will be introduced as they become available.



Quote:
Boeing latest predictions say that the 747-8F will have a better than expected reduction in fuelburn cash operating cost relative to the -400F. “Our goal was 12% better, and right now we thing we’re closer to 16%” says teal”

This must be good news for Lufthansa. Even thought they get it late, the plane will perform better than anticipated. The 747-8I and -8F might be worth the wait?

[Edited 2008-11-29 14:32:50]


Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
40 replies: All unread, showing first 25:
 
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5722 posts, RR: 11
Reply 1, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9511 times:

But I thought we'd heard recently by certain European members that the numbers for the 748 had been revised DOWNWARD.

So which is it?


User currently offlineKappel From Suriname, joined Jul 2005, 3533 posts, RR: 17
Reply 2, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9474 times:



Quoting AA737-823 (Reply 1):
But I thought we'd heard recently by certain European members that the numbers for the 748 had been revised DOWNWARD.

I believe the numbers relative to the a380 were revised downward by Boeing, not purely the 748 numbers.



L1011,733,734,73G,738,743,744,752,763,772,77W,DC855,DC863,DC930,DC950,MD11,MD88,306,319,320,321,343,346,ARJ85,CR7,E195
User currently offlineVirgin747LGW From United Kingdom, joined Mar 2007, 225 posts, RR: 0
Reply 3, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9459 times:



Quoting AA737-823 (Reply 1):
But I thought we'd heard recently by certain European members that the numbers for the 748 had been revised DOWNWARD.

to be fair they were commenting on figures released by Boeing, you make it sound like false claims were being made


User currently offlineBlueShamu330s From UK - England, joined Sep 2001, 2857 posts, RR: 25
Reply 4, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9445 times:



Quoting AA737-823 (Reply 1):
But I thought we'd heard recently by certain European members that the numbers for the 748 had been revised DOWNWARD.

No, they were merely quoting Boeing's revised figures, and as far as I recall, they're American.  Smile

Thought can be a dangerous thing  Wink



So I drive a 4x4. So what?! Tax the a$$ off me for it...oh, you already have... :-(
User currently onlineStitch From United States of America, joined Jul 2005, 30548 posts, RR: 84
Reply 5, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9410 times:
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So the 747-8 is better then expected against the 747-400 and worse then expected against the A380-800. Which makes it a better freighter and a worse airliner. Since her future is as a freighter, I consider the program tracking in a good way.

User currently offlineTrijetsRMissed From United States of America, joined Oct 2006, 2323 posts, RR: 7
Reply 6, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9374 times:



Quoting AA737-823 (Reply 1):
But I thought we'd heard recently by certain European members that the numbers for the 748 had been revised DOWNWARD.

So which is it?

Obviously, it can be both. As the A380 continues to perform well, the advantage relative to the Airbus decreases. Perhaps, the expected 4% fuelburn improvement on the 748 is less than the expected improvements with the A380.



There's nothing quite like a tri-jet.
User currently offlineRedChili From Norway, joined Jul 2005, 2213 posts, RR: 4
Reply 7, posted (5 years 7 months 3 weeks 6 days 3 hours ago) and read 9338 times:

So, both the 380 and the 748 will turn out to be better airplanes than first expected. That's good news for the airlines that have bought them, and good news for those of us who would like to stop something else than boring twins.


Top 10 airplanes: B737, T154, B747, IL96, T134, IL62, A320, MD80, B757, DC10
User currently offlineArniepie From Belgium, joined Aug 2005, 1265 posts, RR: 1
Reply 8, posted (5 years 7 months 3 weeks 6 days 1 hour ago) and read 9160 times:

All somewhat dubious statements IMHO for an airliner that hasn't even been build yet ,let alone flew even 1 meter up until today.

History told us that up until now not even the best simulation programs seem to give a 100% accurate prediction of the efficiency of a new airliner (777 better than expected, MD11 worse,...) maybe we should practise a little patience and wait until it really gets airborne.



[edit post]
User currently offlineC680 From United States of America, joined Apr 2005, 588 posts, RR: 0
Reply 9, posted (5 years 7 months 3 weeks 6 days 1 hour ago) and read 9134 times:



Quoting Arniepie (Reply 8):
maybe we should practise a little patience and wait until it really gets airborne.

very wise..

..but not much fun!  Wink



My happy place is FL470 - what's yours?
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5722 posts, RR: 11
Reply 10, posted (5 years 7 months 3 weeks 6 days 1 hour ago) and read 9097 times:



Quoting TrijetsRMissed (Reply 6):
Obviously, it can be both. As the A380 continues to perform well, the advantage relative to the Airbus decreases. Perhaps, the expected 4% fuelburn improvement on the 748 is less than the expected improvements with the A380.

Perfect explanation, thank you.

Quoting Virgin747LGW (Reply 3):
to be fair they were commenting on figures released by Boeing, you make it sound like false claims were being made

I was asking a genuine question- sorry if I came across that way.

Quoting BlueShamu330s (Reply 4):
Thought can be a dangerous thing

How would you know?


User currently offlineKen777 From United States of America, joined Mar 2004, 8187 posts, RR: 8
Reply 11, posted (5 years 7 months 3 weeks 5 days 22 hours ago) and read 8689 times:



Quoting AA737-823 (Reply 10):
How would you know?

He's a Brit - they know our history well.  Smile

As for projecting performance, what modern commercial jet hasn't sold prior to first flight based on engineers best estimates of performance?


User currently offlineBoeingdotcom From Singapore, joined Nov 2008, 89 posts, RR: 0
Reply 12, posted (5 years 7 months 3 weeks 5 days 22 hours ago) and read 8539 times:

Since 90% of the design is released, maybe the 10% is the wing, tail and elevator design? I would expect a whole new wing. Boeing, stop being stubborn! Change the wing if you need, just like how the first B7E7 and B787... So, expect a new wing, elevator or tail design.

Just my 1 cent.



Never forget to be yourself.
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12128 posts, RR: 52
Reply 13, posted (5 years 7 months 3 weeks 5 days 21 hours ago) and read 8202 times:



Quoting Boeingdotcom (Reply 12):
Since 90% of the design is released, maybe the 10% is the wing, tail and elevator design? I would expect a whole new wing. Boeing, stop being stubborn! Change the wing if you need, just like how the first B7E7 and B787... So, expect a new wing, elevator or tail design.

That is a little late now, since the first metal for B-747-8F #1 has already been cut. For a completely new wing and tail surfaces, you are really talking about a new model, perhaps a B-747-9F/I?

Quoting OyKIE (Thread starter):
In this week’s Aviation Week there is an article talking about the 748i that is being pushed back. There are some interesting comments concerning the program. I found them so interesting that I believe it qualifies for a thread of its own.
Here are some quotes from the article November 24. 2008. Page 24
[qoute] The issues began in 2007 when test revealed higher than expected loads on the aircraft’s new supercritical wing, particularly at low speeds. Although the wing is all-new, its planform is the same as the -400’s and the configuration at the root is the same. “Putting that additional load through the same shape required the biggest amount of strengthening”

Quote:
The loads on the wing at lower speed also shifted the center of gravity further aft, requiring a higher balancing tail load.



Quote:
The other focus for Boeing is on “essentially getting the performance of the aircraft to what the customers need.



Quote:
“We’re an 8000 nautical mile aircraft and this is where we need to be. The A380 coming out of the gate is not, so we have the ability to beat that.



Quote:
Additional weight-saving “opportunities” are being defined for aircraft beyond the first -8F. These will be introduced as they become available.



Quote:
Boeing latest predictions say that the 747-8F will have a better than expected reduction in fuelburn cash operating cost relative to the -400F. “Our goal was 12% better, and right now we thing we’re closer to 16%” says teal” [/quote]

A link to the entire story, so all of us can read it would have been nice.

Quoting Arniepie (Reply 8):
All somewhat dubious statements IMHO for an airliner that hasn't even been build yet ,let alone flew even 1 meter up until today.

History told us that up until now not even the best simulation programs seem to give a 100% accurate prediction of the efficiency of a new airliner (777 better than expected, MD11 worse,...) maybe we should practise a little patience and wait until it really gets airborne.

Boeing has traditionaly used wind tunnel testing to predict the efficiency of new airliners (at leats going back to the B-367-80/KC-135/B-707). The wind tunnel testing, as Boeing does it, has always shown actual fuel comsumption numbers to be even more conservitive than the wind tunnel numbers.

Now, if you look closely at what is said, in the AW&ST quote, it says "fuel burn cash operating costs". That could mean anything outside of predicted fuel comsumption. It could be more related to the reduction in oil costs, per barrel since last summer's peak of $147/bbl, to todays cost of about $54/bbl.

Today, you cannot compare the current A-380s in service with the projected B-747-8s to go into service in a little over a year from now. Both the current A-380-800s and the new B-747-8F/Is will be the much heavier versions than those produced later in each program. So, it will be the A-380s delivered in 2010 and the B-747-8s delivered later that same year before you can get an accurate comparison between the two airplanes.

I believe that LH will be in the best place to compare both airplanes because they will be the only airline to operate both passenger versions. EK might give you some idea, but they will fly the passenger A-380-800 and the cargo version B-747-8F.


User currently offlineDfwRevolution From United States of America, joined Jan 2010, 960 posts, RR: 51
Reply 14, posted (5 years 7 months 3 weeks 5 days 20 hours ago) and read 8065 times:



Quoting Boeingdotcom (Reply 12):
Since 90% of the design is released, maybe the 10% is the wing, tail and elevator design?

That's now how it works. You can't advance that far in a design by leaving one whole area of the system undefined. If you're at 90% design release, the 10% that is left is detail stuff.


User currently offlineGigneil From United States of America, joined Nov 2002, 16347 posts, RR: 85
Reply 15, posted (5 years 7 months 3 weeks 5 days 20 hours ago) and read 8044 times:



Quoting OyKIE (Thread starter):
Although the wing is all-new, its planform is the same as the -400’s and the configuration at the root is the same.

Every time i read this, i'm like WTF.

Its an all new wing... that is exactly the same.

NS


User currently offlineAstuteman From United Kingdom, joined Jan 2005, 9976 posts, RR: 96
Reply 16, posted (5 years 7 months 3 weeks 5 days 17 hours ago) and read 7354 times:
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Quoting TrijetsRMissed (Reply 6):
As the A380 continues to perform well, the advantage relative to the Airbus decreases.

If there ever was an advantage  scratchchin 

Quoting OyKIE (Thread starter):
Quote:
“We’re an 8000 nautical mile aircraft and this is where we need to be. The A380 coming out of the gate is not, so we have the ability to beat that.

Find this a curious quote.

The only quotes I've heard from customer airlines are that the A380's range capability is a threat to the 748i.
FWIW the respective manufacturers range/payload charts support that.....

Quoting KC135TopBoom (Reply 13):
So, it will be the A-380s delivered in 2010 and the B-747-8s delivered later that same year before you can get an accurate comparison between the two airplanes.

To get a proper comparison, I would have thought we'd need to wait till 2012 when the 748i goes into service...

Quoting KC135TopBoom (Reply 13):
Additional weight-saving “opportunities” are being defined for aircraft beyond the first -8F. These will be introduced as they become available.

I would expect this  checkmark 
And if Boeing manage to bring the initial aircraft out of the factory at spec, despite being heavier, then the 748 should be able to grow its capability in the same way the current A380-800 will.
Would be nice to see the 748 keep the pressure on  thumbsup 

Rgds


User currently offlineOyKIE From Norway, joined Jan 2006, 2717 posts, RR: 4
Reply 17, posted (5 years 7 months 3 weeks 5 days 16 hours ago) and read 7287 times:



Quoting KC135TopBoom (Reply 13):
A link to the entire story, so all of us can read it would have been nice.

I tried yesterday, but was not able to access AW&ST internettsite. Their web pages are very bad, and not easy to nacvigate thru. I find that strange, as I believe the magazine is very good.

Quoting TrijetsRMissed (Reply 6):
Obviously, it can be both. As the A380 continues to perform well, the advantage relative to the Airbus decreases. Perhaps, the expected 4% fuelburn improvement on the 748 is less than the expected improvements with the A380.

 checkmark 

Quoting Astuteman (Reply 16):
The only quotes I've heard from customer airlines are that the A380's range capability is a threat to the 748i.
FWIW the respective manufacturers range/payload charts support that.....

I have read Tim Clark has said this. But I believe the reason he does that, is because he would like the range of the 748 to reach 8300Nm



Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
User currently offlineAlessandro From , joined Dec 1969, posts, RR:
Reply 18, posted (5 years 7 months 3 weeks 5 days 15 hours ago) and read 7048 times:

Anyone care to compare the mentioned aircrafts with the An-124?

User currently offlineAstuteman From United Kingdom, joined Jan 2005, 9976 posts, RR: 96
Reply 19, posted (5 years 7 months 3 weeks 5 days 15 hours ago) and read 6963 times:
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Quoting OyKIE (Reply 17):
I have read Tim Clark has said this. But I believe the reason he does that, is because he would like the range of the 748 to reach 8300Nm

I'm sure he would. If his A380's are going to match or better that range, he'll want the Boeing offering to compete...

Rgds


User currently onlineStitch From United States of America, joined Jul 2005, 30548 posts, RR: 84
Reply 20, posted (5 years 7 months 3 weeks 5 days 9 hours ago) and read 5593 times:
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Quoting Alessandro (Reply 18):
Anyone care to compare the mentioned aircrafts with the An-124?

The An-124's payload is 150t, which matches the A380-800F and the 747-8F is within spitting distance of (134t).

Volume is 1266m3 for the An-124, 938m3 for the A380-800F and 833m3 for the 747-8F.

I am sure the An-124's load-limit is higher then the 747-8F's, which itself is higher then the A380-800F's.

Range at 150t is 4500km for the An-124 and 10400km for the A380-800F. At 134t, range for the 747-8F is 8275km.

No figures for fuel burn, but the 747-8F should be a bit better then the A380-800 and both should be significantly better then the An-124.


User currently offlineOyKIE From Norway, joined Jan 2006, 2717 posts, RR: 4
Reply 21, posted (5 years 7 months 3 weeks 5 days 7 hours ago) and read 5077 times:



Quoting OyKIE (Reply 17):
I tried yesterday, but was not able to access AW&ST internettsite. Their web pages are very bad, and not easy to nacvigate thru. I find that strange, as I believe the magazine is very good.

The web page is up and running again. Here is the link to the story:

http://www.aviationweek.com/aw/gener...p?channel=comm&id=news/747-8EX.xml



Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
User currently offlineLightsaber From United States of America, joined Jan 2005, 12874 posts, RR: 100
Reply 22, posted (5 years 7 months 3 weeks 5 days 6 hours ago) and read 4852 times:
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Quoting OyKIE (Reply 17):
I have read Tim Clark has said this. But I believe the reason he does that, is because he would like the range of the 748 to reach 8300Nm

 checkmark 

Although at the long range I can only think of one route that clearly calls for a 748I over a longer range A388: SEA. Ok, possibly ATL. Every other EK destination that calls for a VLA would be well served with an 'abused' A388.

Quoting Astuteman (Reply 19):
If his A380's are going to match or better that range, he'll want the Boeing offering to compete...

So true. If the A388 is proven capable to do 8,300nm, which should happen with 2012 deliveries... then there is little incentive to have a 2nd fleet for EK. Of course they are notorious for bidding A vs. B and switching vendors. EK might wish a 748I subfleet just to keep Airbus pricing 'honest.'  Wink

Oh for those saying the projected A388 performance improvement is less than 4%  no 

Plans are for:
6 Metric ton decrease in A388 weight (to get down to original promise)
2% reduction in airframe drag (a la what Boeing did with the 77W. Same magnitude)
2% reduction in engine fuel burn.

With these three combined, we're looking at > 5% increase in range...  hyper 

Lightsaber



Societies that achieve a critical mass of ideas achieve self sustaining growth; others stagnate.
User currently onlineStitch From United States of America, joined Jul 2005, 30548 posts, RR: 84
Reply 23, posted (5 years 7 months 3 weeks 5 days 5 hours ago) and read 4620 times:
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Is reaching the western edge of North America really "abusing" an A380-800? I know headwinds can be an issue, but why not just fly both legs eastbound and gain the tailwind?

User currently offlineAirNZ From , joined Dec 1969, posts, RR:
Reply 24, posted (5 years 7 months 3 weeks 5 days 5 hours ago) and read 4511 times:



Quoting KC135TopBoom (Reply 13):
Today, you cannot compare the current A-380s in service with the projected B-747-8s to go into service in a little over a year from now. Both the current A-380-800s and the new B-747-8F/Is will be the much heavier versions than those produced later in each program. So, it will be the A-380s delivered in 2010 and the B-747-8s delivered later that same year before you can get an accurate comparison between the two airplanes.

It seems that as usual you are ignoring certain facts presented by Boeing themselves.......that the 748 schedule has been pushed back. Whilst the first pieces of metal have been seemingly cut, the aircraft has not even yet begun to be assembled plus still some design to be finalised, how are you seriously stating that the 784 will start to be delivered in 2010?


25 RedChili : According to the current schedule, Boeing actually expects to deliver the first 748i in second quarter 2011. That schedule could easily slip another
26 EBJ1248650 : Once again the 748i is being compared to the A380 and there's no comparison! The two airplanes fill entirely different niches in the airline world.
27 Astuteman : That's ok, but pretty much the rest of the industry, including Boeing by the way (and Airbus), continues to do just that. That should tell us somethi
28 Dynamicsguy : Every time i read this, i'm like WTF. Its an all new wing... that is exactly the same. It's a completely different loft which has the same planform.
29 Post contains links Zeke : Which means less lift is available on the wing to lift payload, some of the lift on the wing has to counter the additional down force on the tailplan
30 Dw747400 : Doesn't moving the CG aft reduce the need for down force on the tail? Am I misreading something?
31 NA : That would mean no 747 deliveries for more than two years. If it leads to an excellent and better-than-expected aircraft, fine. That the 748 freighte
32 ThrottleHold : Moving the CG aft increases the moment forward of the GG. Therefore an increase in tail downforce is required to balance it. A simple comparison: Try
33 Virgin747LGW : Im sure the 748F will be an amazing freighter but to say it will be the best ever is going a bit too far
34 NA : There is no competition, so it´ll be the best, state-of-the-art so to say.
35 Zeke : I had assumed that the CoP went rearwards as well, and the thrust line a little further down with the slightly larger engine.
36 Scbriml : I don't think your analogy works - when you move your finger, the CG of the remote doesn't change - all you're doing is moving the pivot point (which
37 Stitch : While the 747-8F might not be the most voluminous or able to lift the most payload or fly the farthest, for your average general commercial cargo car
38 Leskova : It'll be the "best available", and I'm quite sure that not too many will argue with that. I'll take a guess that it was the word "ever" that Virgin74
39 SunriseValley : Do I understand that Boeing is saying in the Aviation Week piece that they think the fuel burn will be 3 to 4% less with the revised weights or are th
40 OyKIE : The goal was initially 12% better fuelburn. Now they are closer to 16% better fuelburn. I think this might be the engines that GE has been able to ma
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