Why does specific fuel consumption decrease with altitude?

Fuel flow decreases as air density decreases. The engine becomes more efficient because of the greater temperature differential between inlet and exhaust gases combined with the lower fuel flow. Altitude increases – Air density reduces – Mass flosw reduces – Maximum thrust reduces.

Why do jet engines use less fuel at higher altitudes?

Jet engines work more efficiently at high altitude because the air is cooler. Hence, the larger the expansion of the air when heated, the faster the aircraft moves because it is the expansion of air that drives the turbines of the jet engine which generates more power for lesser fuel burn.

Does specific fuel consumption increase with altitude?

When both thrust and fuel flow are reduced, SFC should remain literally constant. But combustion efficiency deteriorates with altitude which requires more fuel to produce same energy than at lower altitude. So, SFC increases at altitude.

Why specific fuel consumption of CI engine is lower than SI engine?

Explanation: The specific fuel consumption of a Cl engine is lower than that of an SI engine because the calorific value of diesel fuel is slightly lower than the petrol fuel and also diesel fuel is denser than petrol and contains more energy by volume.

Why is specific fuel consumption important?

Specific fuel consumption (SFC) is one of the most important metrics employed in aviation. It is important not only in aircraft design but also in the operation of the aircraft. First and foremost, SFC indicates how efficiently a power plant converts chemical into mechanical energy.

Why do airplanes fly faster at high altitudes?

The higher the better One of the central reasons behind aircraft altitude is that, as the air gets thinner with every foot climbed, planes can travel more easily and therefore move faster and burn less fuel, saving money.

Why does thrust decrease as airspeed increases?

If we only consider the change in airflow velocity in the thrust equation, then thrust decreases with an increase in airspeed. This is due to the compressibility of airflow as velocity increases toward supersonic. As airflow becomes compressible, mass due to ram effect increases at an increasing rate.

Why specific fuel consumption in petrol engine is higher than diesel?

Because diesel fuel contains more energy per gallon, diesel engines travel farther per gallon. That is to say, because diesel contains more energy than gasoline, diesel engines are more fuel efficient than gasoline engines.