Combat radius
Combat radius refers to the distance
Distance is a numerical description of how far apart objects are. In physics or everyday discussion, distance may refer to a physical length, or an estimation based on other criteria . In mathematics, a distance function or metric is a generalization of the concept of physical distance...

 from an airbase
An airbase is a military airfield that provides basing and support of military aircraft....

 that a warplane can reach, patrol there for a set amount of time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....

 and return to base with minimal fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

 left, thus completing a combat
Combat, or fighting, is a purposeful violent conflict meant to establish dominance over the opposition, or to terminate the opposition forever, or drive the opposition away from a location where it is not wanted or needed....

 mission. For a given aircraft, its combat radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...

 varies according to whether or not it carries external drop tanks, the level (altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...

) of the combat mission, and the amount and weight of ordnance
Aircraft ordnance
Aircraft ordnance or ordnance is weapons used by aircraft. The term is often used when describing the weight of air-to-ground weaponry that can be carried by an aircraft or the weight that has been dropped...

 it is carrying:
  • An aircraft with drop tanks will have a greater combat radius than the same one without, due to the extra amount of fuel carried.
  • An aircraft engaged in a low-level (lo) combat mission will have a smaller combat radius than the same one engaged in a high-level (hi) mission, due to higher fuel consumption at lower altitudes (higher atmospheric pressure
    Atmospheric pressure
    Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

     / air density
    Density of air
    The density of air, ρ , is the mass per unit volume of Earth's atmosphere, and is a useful value in aeronautics and other sciences. Air density decreases with increasing altitude, as does air pressure. It also changes with variances in temperature or humidity...

  • An aircraft with more and heavier ordnance will have a smaller combat radius than the same one with less and lighter ordnance, due to higher fuel consumption at heavier weights.

The combat radius of an aircraft is often given with its mission profile (without in-air refueling
Aerial refueling
Aerial refueling, also called air refueling, in-flight refueling , air-to-air refueling or tanking, is the process of transferring fuel from one aircraft to another during flight....

). For example:
  • The F-16 Fighting Falcon
    F-16 Fighting Falcon
    The General Dynamics F-16 Fighting Falcon is a multirole jet fighter aircraft originally developed by General Dynamics for the United States Air Force . Designed as an air superiority day fighter, it evolved into a successful all-weather multirole aircraft. Over 4,400 aircraft have been built since...

    's combat radius is 550 km (340 mi) on a hi-lo-hi mission with six 450 kg (1,000 lb) bombs.
  • The F/A-18 Hornet
    F/A-18 Hornet
    The McDonnell Douglas F/A-18 Hornet is a supersonic, all-weather carrier-capable multirole fighter jet, designed to dogfight and attack ground targets . Designed by McDonnell Douglas and Northrop, the F/A-18 was derived from the latter's YF-17 in the 1970s for use by the United States Navy and...

     has a combat radius of 537 km (330 mi) on a hi-lo-lo-hi mission.

Combat radius is always smaller than maximum range, the distance which the aircraft can fly the farthest with maximum payload and without refueling, or ferry range, the distance the aircraft can fly the farthest with drop tanks, no ordnance and without refueling.
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