tonyban
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Why Didn't Boeing Extend The 747 Upper Deck?

Thu Apr 15, 2010 3:32 pm

Hello all and my apologies if this has been discussed before as I couldn't find the relavant topic.

My question, why didn't Boeing extend the upper deck of the 747 as a direct competion to the A380 ? Since Boeing already had an established winner in the 747, one would assume the engineering already existed for Boeing and the development costs may not have been that high. Or was it that Boeing just didn't think it was necassary to compete in this market anymore.
Again, apologies if this topic is old !
 
MCIGuy
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Thu Apr 15, 2010 3:41 pm

The idea has come up more than once. In fact, there was even a model created with two decks all the way to the tail but I can't even find a picture of it anymore. My understanding is that not only would it have required a complete wing/box redesign, but even with the new wing there'd have been a huge range penalty, but that's just my understanding.
Boeing decided that an all-new design was required in order to haul that many people that far and came up with the "Boeing NLA", but decided there wasn't enough market for it and it wasn't pursued further.


Boeing NLA Concept
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tonyban
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Thu Apr 15, 2010 4:52 pm

thanks for the response MCIGuy......
 
B6JFKH81
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Thu Apr 15, 2010 6:06 pm

The upper deck on the 748i has been made larger than the 744 from what I remember, although on the 748F it is not. Boeing actually mentions the A380 in the product information for the 748 family:

http://boeing.com/commercial/747family/747-8_facts.html
"If you do not learn from history, you are doomed to repeat it"
 
dw747400
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Thu Apr 15, 2010 10:43 pm

Keep in mind, stretching the fuselage, in its simplest form, only involves sticking a plug that is the same diameter and shape of the existing fuselage on the plane. In fact, the 747 was desgined with two "break points" where constant-cross section plugs could be inserted both in front of and behind the wing. I'm not sure if these align with what was ultimately done on the 748, but the point is a stretch is a relatively simple change.

Adding a second deck would be much more challenging, and require completely reprofiling the entire fuselage aft of the existing deck. In addition, the 3-3 layout of the upper deck would result in extensive boarding times and cause evacuation problems. After deplaning a 737-800, try imaging a cabin 50+ feet longer. It isn't the most efficent way of adding passengers either--again, at most the upper deck is 3-3.

Thus, the solution was either an all new airplane, as above, or a conventional stretch of the 747. The full length upper deck just required to many engineering resources and had to many logisitical problems when compared to a short stretch that would provide a comperable increase in seating.
CFI--Certfied Freakin Idiot
 
EMBQA
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Thu Apr 15, 2010 11:06 pm

Boeing looked at doing it back in the late 1980's early '90s. The biggest reason is that Boeing did not see a profit to investment in doing the project... and so far it looking at the sales numbers to investment that Airbus has, they were right.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
Viscount724
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Fri Apr 16, 2010 1:13 am

Quoting dw747400 (Reply 4):
It isn't the most efficent way of adding passengers either--again, at most the upper deck is 3-3.

The upper deck also has small overhead bins since the cabin ceiling is close to the fuselage skin.
 
tonyban
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Fri Apr 16, 2010 3:58 pm

thank you to all who replied.
 
Boiler905
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Fri Apr 16, 2010 7:43 pm

Quoting EMBQA (Reply 5):
The biggest reason is that Boeing did not see a profit to investment in doing the project... and so far it looking at the sales numbers to investment that Airbus has, they were right.

Bingo. There isn't really a demand for a commercial aircraft with that capacity.

I have noticed that the carriers who do currently operate A380's have been moving the aircraft around to different markets (my guess would be because they're trying to find city pairs that will actually give them acceptable load factors). Just a guess though.
Boiler Up
 
A342
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Fri Apr 16, 2010 9:51 pm

Quoting Boiler905 (Reply 8):
I have noticed that the carriers who do currently operate A380's have been moving the aircraft around to different markets

Maybe you can tell us a few examples where operators have been shifting it around, apart from EK retracting it from the JFK route and re-introducing it again?
Exceptions confirm the rule.
 
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Stitch
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Fri Apr 16, 2010 11:45 pm

Quoting tonyban (Thread starter):
My question, why didn't Boeing extend the upper deck of the 747 as a direct competion to the A380?

They floated multiple extensions to the upper deck, including the 747-500X, 747-600X, and the 747-X family.


Boeing 747-400X / 747-500X / 747-600X Concepts


Boeing 747-X Family


[Edited 2010-04-16 16:46:40]
 
Woosie
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Sat Apr 17, 2010 6:14 am

" In fact, the 747 was desgined with two "break points" where constant-cross section plugs could be inserted both in front of and behind the wing. I'm not sure if these align with what was ultimately done on the 748, but the point is a stretch is a relatively simple change."

All airplanes use the same basic concept to stretch - by adding plugs fore and aft of the wing. Engine location and engine weight changes dictate the length of fuselage plug sections; they may be unequal (typical of aft engine mounted airplanes) or fairly symmetrical (typical of wing-mounted twin or quad jets).

In the case of the MD-90, only a forward plug was added, to account for the increased engine weight (V2525 vs JT8D-19 for MD-80); in fact, the amount of stretch added to the forward plug necessitated movement of the forward overwing exit doors one window plug forward. That's how you can easily tell a MD-90 from other Douglas twinjet models - the MD-90 has two windows between the overwing exit doors.

The only criteria for a fuselage plug is that it occurs in a constant fuselage section; for ease of manufacture, chances are (I don't know for sure) that fuselage plugs were added at existing section breaks in the fuselage constructions, so existing sectional tooling don't need to be revised.
 
tdscanuck
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Sat Apr 17, 2010 7:02 pm

Quoting Woosie (Reply 11):
The only criteria for a fuselage plug is that it occurs in a constant fuselage section; for ease of manufacture, chances are (I don't know for sure) that fuselage plugs were added at existing section breaks in the fuselage constructions, so existing sectional tooling don't need to be revised.

Fuselage plugs are almost never added as a separate component. For example, the only difference (in fuselage, not including doors) between the 737-600/700/800/900 is fuselage plugs, but all four aircraft have exactly the same number of section breaks. The sections are just different lengths. The "plug" is a conceptual change, not usually a literal part.

Tom.
 
A342
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Sat Apr 17, 2010 8:12 pm

Quoting tdscanuck (Reply 12):
Fuselage plugs are almost never added as a separate component. For example, the only difference (in fuselage, not including doors) between the 737-600/700/800/900 is fuselage plugs, but all four aircraft have exactly the same number of section breaks. The sections are just different lengths. The "plug" is a conceptual change, not usually a literal part.

Interesting. Do you know if that's also the case for the CRJ-700/900/1000, Fokker 70/100 and Tupolev Tu-204?

The reason I'm asking is that Bombardier converted a CRJ-700 prototype into the CRJ-900 prototype and are doing the same with the -1000 (-900 to -1000):

"Assembly of the prototype CRJ900 began in the fall of 2000 at the Montreal Mirabel factory. Shorts in Belfast delivered two plugs, measuring 2,29 m and 1,57 m. These were mated to the CRJ700 prototype serial number 10001 in September 2000 to create prototype CRJ900 serial number 15991."

http://flug-revue.rotor.com/FRTypen/FRCRJ900.htm

Fokker did the same, shortening the F100 prototype to create the F70:

"Construction of the first Fokker 70 began in 1992 with removing two fuselage plugs from the second Fokker 100 prototype - one forward of the wing and one rear of the wing."

http://aerofavourites.nl/fok100-04.htm

And at least one Tu-204-100 was converted to the shorter -300 variant and is now in service with a private/executive operator.
Exceptions confirm the rule.
 
Woosie
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Sun Apr 18, 2010 12:11 am

Quoting tdscanuck (Reply 12):
Fuselage plugs are almost never added as a separate component. For example, the only difference (in fuselage, not including doors) between the 737-600/700/800/900 is fuselage plugs, but all four aircraft have exactly the same number of section breaks. The sections are just different lengths. The "plug" is a conceptual change, not usually a literal part.

Tom - if that's how Puget Sound does fuselage length differences, then I'm corrected. Plugs are used in MDC airplanes, as I described above.

Now I know something new about PS airplanes - I spend nearly all my time in Systems, so I'm not as familiar with the structural aspects of 7-series models!
 
tdscanuck
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RE: Why Didn't Boeing Extend The 747 Upper Deck?

Sun Apr 18, 2010 1:20 am

Quoting A342 (Reply 13):
Interesting. Do you know if that's also the case for the CRJ-700/900/1000, Fokker 70/100 and Tupolev Tu-204?

The reason I'm asking is that Bombardier converted a CRJ-700 prototype into the CRJ-900 prototype and are doing the same with the -1000 (-900 to -1000):

I don't know the details on those models, but it certainly makes sense to do a prototype that way (much cheaper). However, once you've done the prototype, I'm not sure why you'd do full rate production that way. More parts and more splices means more weight and complexity that's pretty easily avoided.

Quoting Woosie (Reply 14):
Tom - if that's how Puget Sound does fuselage length differences, then I'm corrected. Plugs are used in MDC airplanes, as I described above.

I should have been a lot more specific there...yeah, I'm just talking Puget Sound-heritage Boeings. I don't have a very good feel for structural design on the MDC aircraft at all, other than some basics on their splice preferences.

Tom.

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