4 ms·

I think the instantaneous fuel consumption at take-off vs. a very long glide down could in fact be 1000x, but is at least 100x. So I ask, what do your numbers r

by labawi 7y ago

I think the instantaneous fuel consumption at take-off vs. a very long glide down could in fact be 1000x, but is at least 100x. So I ask, what do your numbers represent? EDIT: "747-400 has eight fuel tanks, with a combined capacity of 57,164 gallons of Jet-A fuel"[1]. So around 30-40k gal for a typical trans-oceanic flight? Meaning 1 gal per 1 second of flight time should be within order of magnitude, but far from take-off or peak consumption. [1] http://www.boeing-747.com/boeing-747-internals/fuel-system.html http://www.boeing-747.com/boeing-747-internals/fuel-system.h...

mehrdadn 7y ago
> So I ask, what do your numbers represent? And I said, it's right there if you actually take 5 seconds to Google. Literally the top result [1] says [2] that for a medium-haul flight (3,240–6,300 km), a 747-800 burns 9.9 kg/km of fuel, which at 917 km/h and 0.81 kg/L density, comes out to 0.82 gal/s if I'm doing my math correctly. So I guess my bad for being off by a whopping... 20%? Like I said, I'm all ears if you have better numbers, but it's quite inconsiderate to just casually dismiss what people say with so little effort and force them to spend 20 minutes to respond. [1] https://www.google.com/search?q=plane+fuel+consumption https://www.google.com/search?q=plane+fuel+consumption [2] https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Medium-haul_flights https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Mediu...
- senordevnyc 7y ago
  I mean, didn’t this entire thread start because you took issue with the word “thousands” in the headline, even though it’s technically correct? :)
  - maxfan8 7y ago
    It sounded like dataflow was doing a Fermi estimate, which usually need to be within one order of magnitude of the real answer to be considered decent. I think the reason why they didn’t like the headline was because it seemed like it was several orders of magnitude off.

by labawi 7y ago

mehrdadn 7y ago

> So I ask, what do your numbers represent? And I said, it's right there if you actually take 5 seconds to Google. Literally the top result [1] says [2] that for a medium-haul flight (3,240–6,300 km), a 747-800 burns 9.9 kg/km of fuel, which at 917 km/h and 0.81 kg/L density, comes out to 0.82 gal/s if I'm doing my math correctly. So I guess my bad for being off by a whopping... 20%? Like I said, I'm all ears if you have better numbers, but it's quite inconsiderate to just casually dismiss what people say with so little effort and force them to spend 20 minutes to respond. [1] https://www.google.com/search?q=plane+fuel+consumption https://www.google.com/search?q=plane+fuel+consumption [2] https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Medium-haul_flights https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Mediu...

senordevnyc 7y ago
I mean, didn’t this entire thread start because you took issue with the word “thousands” in the headline, even though it’s technically correct? :)
- maxfan8 7y ago
  It sounded like dataflow was doing a Fermi estimate, which usually need to be within one order of magnitude of the real answer to be considered decent. I think the reason why they didn’t like the headline was because it seemed like it was several orders of magnitude off.