I wouldn't think it is expensive to buy on a per-seat basis, which is the relevant measure to
use in answering this question.
Not only is the 747-8 in the running if you include cargo, but the soon-to-be available A350 and the 787-9/10 would also be in the same ballpark. At least, that is what I gather from what is available on the web.
The 757-300 is very efficient if you don't consider cargo capacity, but certainly not as efficient as an A380 operating at its design range. But my guess is that for US Transcon range or shorter, it beats any widebody older than the 787-8.
Flyf15 From , joined Dec 1969, posts, RR:
Reply 8, posted (7 years 1 month 2 weeks 4 days 20 hours ago) and read 7000 times:
This should answer most of your questions. It looks like until the introduction of the A380, the A330-300 was most efficient. The A380 barely edges out the A330-300, and the 787-8 when in commercial service, will barely edge out the A380.
WingedMigrator From United States of America, joined Oct 2005, 2322 posts, RR: 56
Reply 9, posted (7 years 1 month 2 weeks 4 days 19 hours ago) and read 6990 times:
My meager contribution, from a model based on the Breguet range equation. Stage length is 6000 nm, and payload is 1 pax (95 kg) per square meter of cabin floor area. This chart was created before the 787 was delayed and got heavier.
The evolution of fuel burn, at 1 pax / m2, with more types added
A lot of people seem to have the mistaken impression that the C-5 is bigger than the A380.
Maybe this is because most people who have seen a C-5 up close have never seen an A380. The A380 is significantly bigger than the C-5 in almost every metric, whether by wing area, MTOW, empty weight, wing span, engine thrust, etc. The C-5 is a shade longer, but that's about it... for the time being
(edit): here's a better SVG version from Wikipedia.
I was asked to add the C-5 but the graphic got too cluttered, and size-wise it isn't even in the top three!
Quoting Flyf15 (Reply 8): It looks like until the introduction of the A380, the A330-300 was most efficient.
Just caught that... it isn't quite so. The charts are for 6000 nm stage lengths, which the A330-300 can't do at that payload. That's why the color code is different, shown for 5000 nm. Also, the crude leveling assumption of 1 pax/m2 does not generally hold true.
The 773ER is often (and correctly) spoken of as the most efficient long range airliner, bar only the A380. That's why I used it as a reference against which to compare everything else.
Quoting Starlionblue (Reply 4):
Heh. Can it be pressurized?
The C-5 is pressurized?
I don't think so, which is why I stated my question.
LOL! Fond memories of blankets, plastic, and chains to seal up the leaks in flight.
For those who don't know, the C-5 commonly experienced pressurization leaks during flight given the massive amount of seals required for it's forward and aft cargo doors. Visor ramp leaks and rear door side leaks seemed to be the most common (IMO). The rear door had two side seals that never seemed to seat right, hence the use of the various materials listed above. But in my dated experience, we never had a case where the crew had to put on their O2 masks. I had one time though where we were limited in altitude because we couldn't fully pressurize.