aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' include fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air aircraft such as h ...

, endurance is the maximum length of time that an aircraft can spend in cruising flight. In other words, it is the amount of time an aircraft can stay in the air with one load of fuel. Endurance is different from

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

, which is a measure of distance flown. For example, a typical

sailplane A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplan ...

exhibits high endurance characteristics but poor range characteristics. Endurance can be defined as: :

E=\int_^dt=-\int_^\frac=\int_^\frac

where W stands for fuel weight, F for fuel flow, and t for time. Endurance can factor into aviation design in a number of ways. Some aircraft, such as the P-3 Orion or U-2 spy plane, require high endurance characteristics as part of their mission profile (often referred to as loiter time (on target)). Endurance plays a prime factor in finding out the

fuel fraction In aerospace engineering, an aircraft's fuel fraction, fuel weight fraction, or a spacecraft's propellant fraction, is the weight of the fuel or propellant divided by the gross take-off weight of the craft (including propellant): :\ \zeta = \fra ...

for an aircraft. Endurance, like range, is also related to

fuel efficiency Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical energy, chemical potential energy contained in a carrier (fuel) into kinetic energy or Mechanical work, w ...

; fuel-efficient aircraft will tend to exhibit good endurance characteristics.

References

Aeronautics {{Aviation-stub