Energy–maneuverability theory is a model of aircraft performance. It was developed by
Col. John Boyd, a fighter pilot, and
Thomas P. Christie, a mathematician with the
United States Air Force
The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
, and is useful in describing an aircraft's performance as the total of
kinetic
Kinetic (Ancient Greek: κίνησις “kinesis”, movement or to move) may refer to:
* Kinetic theory of gases, Kinetic theory, describing a gas as particles in random motion
* Kinetic energy, the energy of an object that it possesses due to i ...
and
potential
Potential generally refers to a currently unrealized ability. The term is used in a wide variety of fields, from physics to the social sciences to indicate things that are in a state where they are able to change in ways ranging from the simple re ...
energies or
aircraft specific energy
Aircraft-specific energy is a form of specific energy applied to aircraft and missile trajectory analysis. It represents the combined kinetic energy, kinetic and potential energy of the vehicle at any given time. It is the total energy of the vehi ...
. It relates the
thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...
,
weight
In science and engineering, the weight of an object is the force acting on the object due to gravity.
Some standard textbooks define weight as a Euclidean vector, vector quantity, the gravitational force acting on the object. Others define weigh ...
,
aerodynamic drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fl ...
,
wing area
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
, and other flight characteristics of an aircraft into a
quantitative model. This allows combat capabilities of various aircraft or prospective design
trade-offs to be predicted and compared.
Formula
All of these aspects of airplane performance are compressed into a single value by the following formula:
:
History
John Boyd, a U.S. jet fighter pilot in the
Korean War
, date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...
, began developing the theory in the early 1960s. He teamed with mathematician
Thomas Christie
Thomas Christie (1761–1796) was a Scottish radical political writer during the late 18th century. He was one of the two original founders of the important liberal journal, the ''Analytical Review''.
Life
Christie was born to Alexander Chris ...
at
Eglin Air Force Base
Eglin Air Force Base is a United States Air Force (USAF) base in the western Florida Panhandle, located about southwest of Valparaiso in Okaloosa County.
The host unit at Eglin is the 96th Test Wing (formerly the 96th Air Base Wing). The ...
to use the base's high-speed computer to compare the
performance envelope
In aerodynamics, the flight envelope, service envelope, or performance envelope of an aircraft or spacecraft refers to the capabilities of a design in terms of airspeed and load factor or atmospheric density, often simplified to altitude. The t ...
s of
U.S.
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
and
Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
aircraft from the Korean and
Vietnam War
The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...
s. They completed a two-volume report on their studies in 1964. Energy Maneuverability came to be accepted within the U.S. Air Force and brought about improvements in the requirements for the
F-15 Eagle
The McDonnell Douglas F-15 Eagle is an American twin-engine, all-weather tactical fighter aircraft designed by McDonnell Douglas (now part of Boeing). Following reviews of proposals, the United States Air Force selected McDonnell Douglas's ...
and later the
F-16 Fighting Falcon
The General Dynamics F-16 Fighting Falcon is a single-engine multirole fighter aircraft originally developed by General Dynamics for the United States Air Force (USAF). Designed as an air superiority day fighter, it evolved into a successful ...
fighters.
[Jenkins, Dennis R. ''McDonnell Douglas F-15 Eagle, Supreme Heavy-Weight Fighter'', p. 7. Aerofax, 1998.]
See also
*
Lagrangian mechanics
In physics, Lagrangian mechanics is a formulation of classical mechanics founded on the stationary-action principle (also known as the principle of least action). It was introduced by the Italian-French mathematician and astronomer Joseph-Lou ...
Notes
References
*Hammond, Grant T. ''The Mind of War: John Boyd and American Security''. Washington, D.C.: Smithsonian Institution Press, 2001. and .
*Coram, Robert. ''Boyd: The Fighter Pilot Who Changed the Art of War''. New York: Back Bay Books, 2002. and .
*
Wendl, M.J., G.G. Grose, J.L. Porter, and V.R. Pruitt
''Flight/Propulsion Control Integration Aspects of Energy Management'' Society of Automotive Engineers
SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE Internatio ...
, 1974, p. 740480.
{{DEFAULTSORT:Energy-maneuverability theory
Aerospace engineering