In flight mechanics, the fuel fraction refers to the proportion of an aircraft’s total takeoff weight that is attributed to the weight of the fuel. It is a key parameter used in aviation to assess fuel efficiency, endurance, and range during various phases of flight, particularly during takeoff. An increase in the fuel fraction results in a higher fuel weight and, consequently, a greater total takeoff weight. The formula to calculate Fuel fraction as follows:
Where:
- : Fuel fraction,Â
- : Fuel weight on board for takeoff.
- : Total takeoff weight of the aircraft.