3 ms·

> roughly the same amount of greenhouse gasses per mile per person as a car I see. How much non-human cargo are these cars carrying? More to the point: ho

> roughly the same amount of greenhouse gasses per mile per person as a car I see. How much non-human cargo are these cars carrying? More to the point: how else do you propose one go from SF to Europe? Reading between the lines, you're either suggesting people stay home or that they take a boat, both of which are absolute crazy talk. EDIT: moreover, wikipedia's numbers suggest jetliners get roughly 70 to 110 passenger-miles/gallon (https://en.wikipedia.org/wiki/Energy_efficiency_in_transportation#Aircraft https://en.wikipedia.org/wiki/Energy_efficiency_in_transport...). I have yet to come across a car that gets that kind of mileage period, let alone per passenger. Besides, gas turbine engines are pretty much the model of efficiency when it comes to hydrocarbon-consuming engines. I don't know where you people are getting your numbers but my BS detector is off the charts.

sokoloff 11y ago
I don't think that turbine engines are the model of efficiency that you claim. On a BSFC basis, they're significantly worse than piston diesels or marine two-strokes. https://en.wikipedia.org/wiki/Brake_specific_fuel_consumption#Examples_of_values_of_BSFC_for_shaft_engines https://en.wikipedia.org/wiki/Brake_specific_fuel_consumptio... (That's for shaft engines, which a turbojet isn't, but the turboprop examples are jet engines with a gearbox and propellor mounted.) Jet engines are incredibly powerful (per unit of mass) and reliable, but I don't think they're incredibly efficient.
- omginternets 11y ago
  Perhaps I don't understand the measure (entirely possible!) but I think thrust-specific fuel consumption is a better indicator here. You need to account for the thrust required in these behemoths: replace the gas turbine engines with piston engines large enough to produce equivalent thrust and I doubt you'll retain the fuel economy. Either way, this is an auxiliary point: the per-passenger fuel economy of airplanes is significantly higher than that of cars.
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sokoloff 11y ago

I don't think that turbine engines are the model of efficiency that you claim. On a BSFC basis, they're significantly worse than piston diesels or marine two-strokes. https://en.wikipedia.org/wiki/Brake_specific_fuel_consumption#Examples_of_values_of_BSFC_for_shaft_engines https://en.wikipedia.org/wiki/Brake_specific_fuel_consumptio... (That's for shaft engines, which a turbojet isn't, but the turboprop examples are jet engines with a gearbox and propellor mounted.) Jet engines are incredibly powerful (per unit of mass) and reliable, but I don't think they're incredibly efficient.

omginternets 11y ago
Perhaps I don't understand the measure (entirely possible!) but I think thrust-specific fuel consumption is a better indicator here. You need to account for the thrust required in these behemoths: replace the gas turbine engines with piston engines large enough to produce equivalent thrust and I doubt you'll retain the fuel economy. Either way, this is an auxiliary point: the per-passenger fuel economy of airplanes is significantly higher than that of cars.

deleted 11y ago

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