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original wing(span) of the 787-9

Posted: Fri Aug 27, 2021 6:54 am
by Taxi645
If I remember correctly the original plan was for the 787-9 to have a slightly larger wing(span) than the 787-8 and that because of reasons like cost and the performance of the 787-8 having proven to be sufficient, Boeing stuck with the 787-8 wing.

Does anybody know the specs of the original wing Boeing intended for the 787-9?

Re: original wing(span) of the 787-9

Posted: Fri Aug 27, 2021 1:01 pm
by 817Dreamliiner
I think it was something along the lines of 63m for the -9 wing.

Re: original wing(span) of the 787-9

Posted: Fri Aug 27, 2021 1:51 pm
by Taxi645
817Dreamliiner wrote:
I think it was something along the lines of 63m for the -9 wing.



Yes, that's more or less what I remember as well, but I can't find a source to confirm.

Re: original wing(span) of the 787-9

Posted: Fri Aug 27, 2021 2:54 pm
by LH707330
I'm tempted to say it was supposed to be 6 feet per side for a total of 209'4", so 63.80.

Re: original wing(span) of the 787-9

Posted: Fri Aug 27, 2021 8:26 pm
by SteelChair
My guess is that when they decided not to do the fold, they standardized the wing.

Re: original wing(span) of the 787-9

Posted: Sat Aug 28, 2021 1:09 am
by zeke
Taxi645 wrote:
Does anybody know the specs of the original wing Boeing intended for the 787-9?


7E7 Facts and Figures
Here are the projected ranges, passenger capacities and wingspans of the three proposed 7E7 models being offered by Commercial Airplanes.

7E7
Range: 7,500 nautical miles
Capacity: 200 passengers in three-class seating
Wingspan: 193 feet

7E7 Stretch
Range: 8,300 nautical miles
Capacity: 250 passengers in three-class seating
Wingspan: 193 feet

7E7 Shorter Range
Range: 3,500 nautical miles
Capacity: 300 passengers in two-class seating
Wingspan: 165-170 feet

from https://www.boeing.com/news/frontiers/a ... i_ca2.html

Close enough to 200 ft.

Also see

http://theaviationspecialist.com/787-3_ga.gif
http://theaviationspecialist.com/787-8_ga.gif
http://theaviationspecialist.com/787-9_ga.gif

from "787 Family Latest Information Release" viewtopic.php?t=356575

Re: original wing(span) of the 787-9

Posted: Sat Aug 28, 2021 5:46 am
by Taxi645
Thank you. From that thread at the bottom: 62.1m for the 787-9 vs 60.2m for the 787-8.

Wonder if that is any indication for the scope for the wingbox to cope with any wingspan increases related to MTOW increases of possible future developments of the 787.

Re: original wing(span) of the 787-9

Posted: Sat Sep 11, 2021 6:35 am
by ADent
IIRC with the weight growth of the 787 caused the 787-9 to be up against the MTOW limit of the landing gear. So the longer wing would be more efficient, but it’s extra weight would actually reduce fuel carried - so in the end it wasn’t worth it.

Re: original wing(span) of the 787-9

Posted: Mon Oct 25, 2021 1:54 pm
by ruizpajares
The B787-8 has the same wing span like the B787-9: 60.1 Meters (197 feet 3 inches).

Re: original wing(span) of the 787-9

Posted: Mon Oct 25, 2021 2:44 pm
by Okcflyer
ruizpajares wrote:
The B787-8 has the same wing span like the B787-9: 60.1 Meters (197 feet 3 inches).


You are correct in that the as-built 789 shares the same wing dims as the 788.

As the OP stated, the original 789 concept called for an enlarged wing relative to the 788.

3 factors lead Boeing to drop the concept for a larger wing on the 789:

1) Budget overruns were already killing the 787 program. They needed to find a way to trim 789 development cost (and risk), and this was one way of doing that.
2) The final 788 wing performance was better than expectations/projections. It would perform "good enough" on the 789 for the majority of missions.
3) The proposed larger wing would have reduced cruise burn and therefore would been advantageous on the longest flights. It also would have competed more equally with today's A359 performance at range. As previously stated, due to how overweight the 787 program was compared to original expectations, the MLG didn't have additional margin to carry this heavier wing by increasing MTOW. Therefore, this heavier but better wing would have reduced available payload (and likely increased fuel burn) on short to mid range flights, which today still makes up a large percentage of the number of flights flown by the type. Boeing's decision to keep the 787 optimized in this middle range is one of the differentiator factors that have helped it against the A359. It's a great jack of all trades.

In short, Boeing determined it was not worth the additional investment (time, risk, and $$$) for improved performance at extreme end of the envelope. It was the right move, IMHO.