Why do jets burn less fuel the higher they fly?

Answer

where there is more pressure there is more resistance to the motion on an object.The atmospheric pressure decreases with hight-more on surface and less and lesser the higher one goes,thus the jets consumes lesser energy on higher level than lower and at period of take-off,simply because there is less air pressure or resistance of motion above.

Answer

Jets travel faster because of less atmospheric friction upon the aircraft. The engines are more efficient because of the colder air. The engines work by heating the air and it then it expands and exits the engine. When the air is colder (it easily gets -40 degrees up there) and the fuel air mixture is burned, the air expands alot more than if warm air was entering the engine. On a warm day a jet will not perform nearly as well as on a cold day.

Answer

Perhaps more to the point of the question would be to explain that the chemical energy in the fuel is a function of the mass of the fuel. Since a gallon of fuel expands or contracts with temperature, a gallon of cold fuel contains more energy than a gallon of warm fuel. As already pointed out, the temperature gets colder the higher you go (up to the tropopause, that is) and consequently, more thrust is derived from each pound of fuel which translates to greater fuel efficiency.

First answer by ID3289983952. Last edit by Joepoidog. Contributor trust: 770 [recommend contributor]. Question popularity: 48 [recommend question]