In comparison to air, gas turbine engine fuel in liquid form is:

Gas turbine engine fuel in liquid form is generally lighter than air due to its lower density. Fuels such as kerosene or Jet A, which are commonly used in gas turbines, have a specific gravity that is significantly lower than that of air. This property is crucial for several reasons in the context of gas turbine engines.

Firstly, the lighter weight of liquid fuel compared to air helps in enhancing the overall efficiency of the engine during operation. A reduction in the weight of the fuel contributes positively to the thrust-to-weight ratio of the aircraft. Moreover, during fuel combustion, lighter fuels can lead to more complete combustion and better thermodynamic efficiency.

Secondly, when considering the aerodynamics of the aircraft, having a fuel that is lighter than air means that its presence in the fuel tanks contributes less to the overall drag of the aircraft when compared to other potential fuels that could be heavier.

Thus, understanding the differences in density between gas turbine fuel and air is essential for optimizing performance within gas turbine engines and contributes to advancements in aerodynamics and engine design.