I read that the empty weight of a 777-9X is higher than that of a 747. Is that true?
If so, why is that? If I'm not mistaken, the 747 was made of aluminum with aluminum wings, but the 777x fuselage is made of Aluminum and Lithium and the wings are made of CFRP. Seems to me that the 777x was built with more advanced materials and holds fewer people and so I'd expect it to be lighter than the 747.
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Re: Empty weight of 777x vs 747
They have about the same cabin area, actually - 779's cabin is much longer. 747 has a higher exit limit but Boeing specifically chose to limit max capacity to save on exit space.
The weight difference is primarily due to 779's much greater wingspan (235ft vs. 213). This makes for a slightly heavier plane but is the main reason for 779's ~17% higher L/D. You'd easily trade 17% higher L/D against a small weight delta.
CFRP saves ~10% wing weight but wing bending weight scales cubically with span, so on net the 777-9's wing will be heavier.
The weight difference is primarily due to 779's much greater wingspan (235ft vs. 213). This makes for a slightly heavier plane but is the main reason for 779's ~17% higher L/D. You'd easily trade 17% higher L/D against a small weight delta.
CFRP saves ~10% wing weight but wing bending weight scales cubically with span, so on net the 777-9's wing will be heavier.
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- OldAeroGuy
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Re: Empty weight of 777x vs 747
shantahan wrote:L/D = load/drag? length/diameter?
Aero performance engineers will recognize L/D = Lift/Drag. It's a primary measure of airframe efficiency.
Re: Empty weight of 777x vs 747
Thanks!
(I saw this in the civil forum before it got moved to tech ops).
(I saw this in the civil forum before it got moved to tech ops).
Re: Empty weight of 777x vs 747
fspro wrote:I read that the empty weight of a 777-9X is higher than that of a 747. Is that true?
Boeing has not formally released OEW figures yet for the 777-9X. Leeham.net projects it will run around 185,000kg and Aspire Aviation states that in four-classes (300 seats) the airframe was at 188,000kg at Revision E. In three classes (406 seats), it was at 164,000kg at Revision E.
The 747-8 Intercontinental in a Boeing three-class OEM configuration (467 seats) is 220,000kg. The 747-400 in a Boeing three-class OEM configuration (416 seats) is 179,000kg.
Re: Empty weight of 777x vs 747
Stitch wrote:fspro wrote:I read that the empty weight of a 777-9X is higher than that of a 747. Is that true?
Boeing has not formally released OEW figures yet for the 777-9X. Leeham.net projects it will run around 185,000kg and Aspire Aviation states that in four-classes (300 seats) the airframe was at 188,000kg at Revision E. In three classes (406 seats), it was at 164,000kg at Revision E.
The 747-8 Intercontinental in a Boeing three-class OEM configuration (467 seats) is 220,000kg. The 747-400 in a Boeing three-class OEM configuration (416 seats) is 179,000kg.
Is the 164,000kg a typo?
Re: Empty weight of 777x vs 747
MoKa777 wrote:Is the 164,000kg a typo?
It's what was written. But note that many on a.net view Aspire Aviation's blog as "junk journalism" and view their content as worthless.
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- WIederling
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Re: Empty weight of 777x vs 747
Stitch wrote:MoKa777 wrote:Is the 164,000kg a typo?
It's what was written. But note that many on a.net view Aspire Aviation's blog as "junk journalism" and view their content as worthless.
ref:
https://web.archive.org/web/20171023174 ... battle.pdf
AspA wrote:• Boeing 777X weight figures revealed for first time
• 3-class 406-seat 777 -9X MEW at 362,000lbs, MZFW 527,000lbs, MLW 557,000lbs
• 4-class 300-seat 777-9X has OEW of 415,000lbs
• 777-9X 8.8% lighter in MZFW per seat than-300ER, 6.3% lighter than A350-1000
translates to metric:
• 3-class 406-seat 777-9X MEW at 164t, MZFW 239t, MLW 253t
• 4-class 300-seat 777-9X has OEW of 188t
so it is orange vs peeled orange or something like that
no apples where harmed in this posting.
I will keep mum about the per seat MZFW number comparison <gnaaagrrr>
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