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Originally Posted by LostCause
It's nice to hear airlines are saving gas, but airplanes are limited in their ability to "hypermile."
Plane's will get their max range (i.e. mileage) when flying at a speed that maximizes their L/D (lift to drag) ratio. The L/D ratio varies with altitude and climatic conditions, but I bet most airlines know exactly where it exists on a given flight in every condition.
Fuel savings also come from modifying the rate of climb, descent, and amount of fuel carried for a flight. There are a lot of variables, but airlines are pretty restricted by regulations. Unfortunately, airlines are pretty much at the complete mercy of fluctuations in fuel prices.
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On many airliners, there's a computer system on-board that calculates the most efficient climb and decent. The article states that the programming may be tweaked.
As far as cruise, any aircraft has a "most-efficient" velocity and often times a faster, more reasonable rate of speed, per the manufacturer. It could simply be that they're using the "sweet spot" instead of "hurry-up and get there".
Of course, there's ATC and other traffic to deal with that eats up the fuel...
Quote:
Originally Posted by hvatum
Domestic flying is pretty environmentally damaging. The jet contrails are higher in the atmosphere so make a more potent GHG. Driving, even by yourself, in a fuel efficient car is better than flying in a full modern plane.
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True, but I don't think it's someplace to start. A full aircraft is more efficient than one that isn't.
For my job, I have to travel -- it's a given. I can either drive and get 25-34 MPG on the trip, or share a ride with 95 other people in a plane and get there quicker, and likely more efficiently (depending on the aircraft).
RH77