Radius of action, combat radius, or combat range in military terms, refers to the maximum distance a ship, aircraft, or vehicle can travel away from its base along a given course with normal load and return without refueling, allowing for all safety and operating factors. A given aircraft's

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

of action varies according to the

altitude Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometr ...

of its

flight plan Flight plans are documents filed by a aviator, pilot or flight dispatcher with the local Air Navigation Service Provider (e.g., the Federal Aviation Administration, FAA in the United States) prior to departure which indicate the plane's planned ...

, amount of weight ( ordnance in a military context) it is carrying, and whether or not it carries external

drop tanks In aviation, a drop tank (external tank, wing tank or belly tank) is used to describe auxiliary fuel tanks externally carried by aircraft. A drop tank is expendable and often capable of being jettisoned. External tanks are commonplace on modern ...

full of fuel. *An aircraft engaged in ''low-level (lo)'' flight will have a smaller radius of action than the same one engaged in a ''high-level (hi)'' mission, due to higher

fuel consumption A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...

at lower altitudes (higher

atmospheric pressure Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013. ...

air density The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere at a given point and time. Air density, like air pressure, decreases with increasing altitude. It also changes with variations in atmosph ...

). *An aircraft with more and heavier load (''ordnance'' in military terms) will have a smaller radius of action (''combat radius'' in military terms) than the same one with less and lighter load, due to higher fuel consumption at heavier weights. *An aircraft with drop tanks will have a greater radius of action than the same one without. In military aviation, the combat radius of an aircraft is often given with its mission profile (without in-air refueling). For example: *The

F-16 Fighting Falcon The General Dynamics F-16 Fighting Falcon is an American single-engine supersonic Multirole combat aircraft, multirole fighter aircraft originally developed by General Dynamics for the United States Air Force (USAF). Designed as an air superio ...

's combat radius is on a ''hi-lo-hi'' mission with six 450 kg (1,000 lb) bombs. *The

F/A-18 Hornet The McDonnell Douglas F/A-18 Hornet is an all-weather supersonic, twinjet, twin-engine, carrier-based aircraft, carrier-capable, Multirole combat aircraft, multirole combat aircraft, designed as both a Fighter aircraft, fighter and attack airc ...

has a combat radius of on a ''hi-lo-lo-hi'' mission. The radius of action of an aircraft is always smaller than its maximum range, the furthest distance the aircraft can fly with maximum payload and without refueling, or ferry range, the furthest distance the aircraft can fly with drop tanks, no load or ordnance and without refueling. The rule of thumb is that the radius of action is one-third the distance an aircraft can fly in a straight line on a full load of fuel. In military aviation, this assumes a trip out and back, plus one-third of fuel for combat operations.

References

Military aviation Radii {{Mil-aviation-stub

See also

References