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Thrust vectoring, also known as thrust vector control (TVC), is the ability of an
aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
,
rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...
or other vehicle to manipulate the direction of 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 ...
from its
engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...
(s) or motor(s) to control the
attitude Attitude or Attitude may refer to: Philosophy and psychology * Attitude (psychology), a disposition or state of mind ** Attitude change * Propositional attitude, a mental state held towards a proposition Science and technology * Orientation ...
or
angular velocity In physics, angular velocity (symbol or \vec, the lowercase Greek letter omega), also known as the angular frequency vector,(UP1) is a pseudovector representation of how the angular position or orientation of an object changes with time, i ...
of the vehicle. In
rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...
ry and
ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typic ...
s that fly outside the atmosphere, aerodynamic control surfaces are ineffective, so thrust vectoring is the primary means of attitude control. Exhaust vanes and gimbaled engines were used in the 1930s by Robert Goddard. For aircraft, the method was originally envisaged to provide upward vertical thrust as a means to give aircraft vertical (
VTOL A vertical take-off and landing (VTOL) aircraft is one that can takeoff and landing, take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust- ...
) or short (
STOL A short takeoff and landing (STOL) aircraft is a fixed-wing aircraft that can takeoff/land on short runways. Many STOL-designed aircraft can operate on airstrips with harsh conditions (such as high altitude or ice). STOL aircraft, including tho ...
) takeoff and landing ability. Subsequently, it was realized that using vectored thrust in combat situations enabled aircraft to perform various maneuvers not available to conventional-engined planes. To perform turns, aircraft that use no thrust vectoring must rely on aerodynamic control surfaces only, such as
aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement aroun ...
s or
elevator An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems suc ...
; aircraft with vectoring must still use control surfaces, but to a lesser extent. In missile literature originating from Russian sources, thrust vectoring is referred to as gas-dynamic steering or gas-dynamic control.


Methods


Rockets and ballistic missiles

Nominally, the
line of action In physics, the line of action (also called line of application) of a force () is a geometric representation of how the force is applied. It is the straight line through the point at which the force is applied, and is in the same direction a ...
of the thrust vector of a rocket nozzle passes through the vehicle's centre of mass, generating zero net
torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...
about the mass centre. It is possible to generate pitch and yaw moments by deflecting the main rocket thrust vector so that it does not pass through the mass centre. Because the line of action is generally oriented nearly parallel to the roll axis, roll control usually requires the use of two or more separately hinged nozzles or a separate system altogether, such as fins, or vanes in the exhaust plume of the rocket engine, deflecting the main thrust. Thrust vector control (TVC) is only possible when the propulsion system is creating thrust; separate mechanisms are required for attitude and flight path control during other stages of flight. Thrust vectoring can be achieved by four basic means:George P. Sutton, Oscar Biblarz, ''Rocket Propulsion Elements'', 7th Edition. * Gimbaled engine(s) or nozzle(s) * Reactive fluid injection * Auxiliary "Vernier" thrusters * Exhaust vanes, also known as jet vanes


Gimbaled thrust

Thrust vectoring for many liquid rockets is achieved by
gimbal A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of ...
ing the whole
engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...
. This involves moving the entire
combustion chamber A combustion chamber is part of an internal combustion engine in which the air–fuel ratio, fuel/air mix is burned. For steam engines, the term has also been used for an extension of the Firebox (steam engine), firebox which is used to allow a mo ...
and outer engine bell as on the Titan II's twin first-stage motors, or even the entire engine assembly including the related
fuel 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 (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...
and
oxidizer An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ''electron donor''). In ot ...
pumps. The
Saturn V The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had multistage rocket, three stages, and was powered by liquid-propel ...
and the
Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...
used gimbaled engines. A later method developed for solid propellant
ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typic ...
s achieves thrust vectoring by deflecting only the
nozzle A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe (material), pipe. A nozzle is often a pipe or tube of varying cross ...
of the rocket using electric actuators or
hydraulic cylinder A hydraulic cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment ( engineering vehicles ...
s. The nozzle is attached to the missile via a ball joint with a hole in the centre, or a flexible seal made of a thermally resistant material, the latter generally requiring more
torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...
and a higher power actuation system. The Trident C4 and D5 systems are controlled via hydraulically actuated nozzle. The STS SRBs used gimbaled nozzles.


Propellant injection

Another method of thrust vectoring used on solid propellant
ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typic ...
s is liquid injection, in which the rocket nozzle is fixed, however a fluid is introduced into the
exhaust Exhaust, exhaustive, or exhaustion may refer to: Law * Exhaustion of intellectual property rights, limits to intellectual property rights in patent and copyright law ** Exhaustion doctrine, in patent law ** Exhaustion doctrine under U.S. law, i ...
flow from injectors mounted around the aft end of the missile. If the liquid is injected on only one side of the missile, it modifies that side of the exhaust plume, resulting in different thrust on that side thus an asymmetric net force on the missile. This was the control system used on the Minuteman II and the early
SLBM A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead ...
s of the
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
.


Vernier thrusters

An effect similar to thrust vectoring can be produced with multiple
vernier thruster A vernier thruster is a rocket engine used on a spacecraft or launch vehicle for fine adjustments to the attitude or velocity. Depending on the design of a craft's maneuvering and stability systems, it may simply be a smaller thruster complement ...
s, small auxiliary combustion chambers which lack their own turbopumps and can gimbal on one axis. These were used on the
Atlas An atlas is a collection of maps; it is typically a bundle of world map, maps of Earth or of a continent or region of Earth. Advances in astronomy have also resulted in atlases of the celestial sphere or of other planets. Atlases have traditio ...
and R-7 missiles and are still used on the Soyuz rocket, which is descended from the R-7, but are seldom used on new designs due to their complexity and weight. These are distinct from
reaction control system A reaction control system (RCS) is a spacecraft system that uses Thrusters (spacecraft), thrusters to provide Spacecraft attitude control, attitude control and translation (physics), translation. Alternatively, reaction wheels can be used for at ...
thrusters, which are fixed and independent rocket engines used for maneuvering in space.


Exhaust vanes

One of the earliest methods of thrust vectoring in rocket engines was to place vanes in the engine's exhaust stream. These exhaust vanes or jet vanes allow the thrust to be deflected without moving any parts of the engine, but reduce the rocket's efficiency. They have the benefit of allowing roll control with only a single engine, which nozzle gimbaling does not. The V-2 used graphite exhaust vanes and aerodynamic vanes, as did the Redstone, derived from the V-2. The Sapphire and Nexo rockets of the amateur group Copenhagen Suborbitals provide a modern example of jet vanes. Jet vanes must be made of a refractory material or actively cooled to prevent them from melting. Sapphire used solid copper vanes for copper's high heat capacity and thermal conductivity, and Nexo used graphite for its high melting point, but unless actively cooled, jet vanes will undergo significant erosion. This, combined with jet vanes' inefficiency, mostly precludes their use in new rockets.


Tactical missiles and small projectiles

Some smaller sized atmospheric tactical
missile A missile is an airborne ranged weapon capable of self-propelled flight aided usually by a propellant, jet engine or rocket motor. Historically, 'missile' referred to any projectile that is thrown, shot or propelled towards a target; this ...
s, such as the AIM-9X Sidewinder, eschew
flight control surfaces Flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude. The primary function of these is to control the aircraft's movement along the three axes of rotation. Flight control surfaces ...
and instead use mechanical vanes to deflect rocket motor exhaust to one side. By using mechanical vanes to deflect the exhaust of the missile's rocket motor, a missile can steer itself even shortly after being launched (when the missile is moving slowly, before it has reached a high speed). This is because even though the missile is moving at a low speed, the rocket motor's exhaust has a high enough speed to provide sufficient forces on the mechanical vanes. Thus, thrust vectoring can reduce a missile's minimum range. For example, anti-tank missiles such as the Eryx and the
PARS 3 LR The PARS 3 LR in German service, also known as TRIGAT-LR (third generation anti-tank, long range) and AC 3G in French, is a fire-and-forget missile, which can be used against air or ground targets. It is intended for long range applications and ...
use thrust vectoring for this reason. Some other projectiles that use thrust-vectoring: * 9M330 * Strix mortar round uses twelve midsection lateral thruster rockets to provide terminal course corrections * Advanced Air Defence missile uses jet vanes * Astra (missile) *
Akash (missile) Akash () is a medium-range mobile surface-to-air missile (SAM) system developed by the Defence Research and Development Organisation (DRDO). The Army and the Air Force variants of the missile system are produced by Bharat Dynamics Limited (BD ...
*
BrahMos The BrahMos (also designated as PJ-10)MPATGM uses jet vanes * Pralay uses jet vanes * QRSAM uses jet vanes * NASM-SR uses jet vanes * AAM-5 * Barak 8 uses jet vanes *
A-Darter The V3E A-Darter (Agile Darter) is a modern short-range infrared homing ("heat seeking") air-to-air missile, featuring countermeasures resistance with a 180-degree look angle and 120-degrees per second track rate, developed by South Africa's Den ...
uses jet vanes *
ASRAAM The Advanced Short Range Air-to-Air Missile (ASRAAM), also known by its United States designation AIM-132, is an imaging infrared homing air-to-air missile, produced by MBDA UK, that is designed for close-range combat. It is in service in the ...
uses jet vanes * R-73 (missile) uses jet vanes * HQ-9 uses jet vanes *
PL-10 (ASR) The PL-10 (, NATO reporting name: CH-AA-9), formerly known as PL-ASR (stands for PiLi-Advanced Short Range), is a short-range, infrared-homing / active radar homing air-to-air missile (AAM) developed by the People's Republic of China. It was desig ...
uses jet vanes * MICA (missile) uses jet vanes *
PARS 3 LR The PARS 3 LR in German service, also known as TRIGAT-LR (third generation anti-tank, long range) and AC 3G in French, is a fire-and-forget missile, which can be used against air or ground targets. It is intended for long range applications and ...
uses jet vanes *
IRIS-T The IRIS-T (infrared imaging system tail/thrust vector-controlled) is a family of short range infrared homing air-to-air missile, air-to-air and short to medium range surface-to-air missile, surface-to-air missiles. It is also called AIM-2000. ...
* Aster missile family combines aerodynamic control and the direct thrust vector control called "PIF-PAF" * AIM-9X uses four jet vanes inside the exhaust, that move as the fins move. * 9M96E uses a gas-dynamic control system enables maneuver at altitudes of up to 35km at forces of over 20''g'', which permits engagement of non-strategic ballistic missiles. *
9K720 Iskander The 9K720 Iskander (; NATO reporting name SS-26 Stone) is a Russian mobile short-range ballistic missile system. It has a range of . It was intended to replace the OTR-21 Tochka in the Russian military by 2020. The Iskander has several differ ...
is controlled during the whole flight with gas-dynamic and aerodynamic control surfaces. * Dongfeng subclasses/ JL-2/ JL-3 ballistic missiles (allegedly fitted with TVC control)


Aircraft

Most currently operational vectored thrust aircraft use
turbofan A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the add ...
s with rotating
nozzle A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe (material), pipe. A nozzle is often a pipe or tube of varying cross ...
s or vanes to deflect the exhaust stream. This method allows designs to deflect thrust through as much as 90 degrees relative to the aircraft centreline. If an aircraft uses thrust vectoring for VTOL operations the engine must be sized for vertical lift, rather than normal flight, which results in a weight penalty.
Afterburning An afterburner (or reheat in British English) is an additional combustion component used on some jet engines, mostly those on military aircraft, military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, ta ...
(or Plenum Chamber Burning, PCB, in the bypass stream) is difficult to incorporate and is impractical for take-off and landing thrust vectoring, because the very hot exhaust can damage runway surfaces. Without afterburning it is hard to reach supersonic flight speeds. A PCB engine, the Bristol Siddeley BS100, was cancelled in 1965.
Tiltrotor A tiltrotor is an aircraft that generates lift (force), lift and thrust, propulsion by way of one or more powered Helicopter rotor, rotors (sometimes called ''proprotors'') mounted on rotating shaft (mechanical engineering), shafts or nacelles ...
aircraft vector thrust via rotating
turboprop A turboprop is a Gas turbine, gas turbine engine that drives an aircraft Propeller (aeronautics), propeller. A turboprop consists of an intake, reduction drive, reduction gearbox, gas compressor, compressor, combustor, turbine, and a propellin ...
engine
nacelle A nacelle ( ) is a streamlined container for aircraft parts such as Aircraft engine, engines, fuel or equipment. When attached entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a Hardpoint#Pylon, pylo ...
s. The mechanical complexities of this design are quite troublesome, including twisting flexible internal components and
driveshaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power, torque, and rotation, usually used to connect ...
power transfer between engines. Most current tiltrotor designs feature two rotors in a side-by-side configuration. If such a craft is flown in a way where it enters a vortex ring state, one of the rotors will always enter slightly before the other, causing the aircraft to perform a drastic and unplanned roll. Thrust vectoring is also used as a control mechanism for
airship An airship, dirigible balloon or dirigible is a type of aerostat (lighter-than-air) aircraft that can navigate through the air flying powered aircraft, under its own power. Aerostats use buoyancy from a lifting gas that is less dense than the ...
s. An early application was the British Army airship ''Delta'', which first flew in 1912. It was later used on HMA (His Majesty's Airship) No. 9r, a British rigid airship that first flew in 1916 and the twin 1930s-era U.S. Navy rigid airships USS ''Akron'' and USS ''Macon'' that were used as airborne aircraft carriers, and a similar form of thrust vectoring is also particularly valuable today for the control of modern non-rigid airships. In this use, most of the load is usually supported by
buoyancy Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of t ...
and vectored thrust is used to control the motion of the aircraft. The first airship that used a control system based on pressurized air was Enrico Forlanini's ''Omnia Dir'' in 1930s. A design for a jet incorporating thrust vectoring was submitted in 1949 to the British Air Ministry by Percy Walwyn; Walwyn's drawings are preserved at the National Aerospace Library at Farnborough. Official interest was curtailed when it was realised that the designer was a patient in a mental hospital. Now being researched, Fluidic Thrust Vectoring (FTV) diverts thrust via secondary fluidic injections. Tests show that air forced into a jet engine exhaust stream can deflect thrust up to 15 degrees. Such nozzles are desirable for their lower mass and cost (up to 50% less),
inertia Inertia is the natural tendency of objects in motion to stay in motion and objects at rest to stay at rest, unless a force causes the velocity to change. It is one of the fundamental principles in classical physics, and described by Isaac Newto ...
(for faster, stronger control response), complexity (mechanically simpler, fewer or no moving parts or surfaces, less maintenance), and
radar cross section Radar cross-section (RCS), denoted σ, also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. An object reflects a limited amount of radar energy b ...
for stealth. This will likely be used in many
unmanned aerial vehicle An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...
(UAVs), and 6th generation
fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...
.


Vectoring nozzles

Thrust-vectoring flight control (TVFC) is obtained through deflection of the aircraft jets in some or all of the pitch, yaw and roll directions. In the extreme, deflection of the jets in yaw, pitch and roll creates desired forces and moments enabling complete directional control of the aircraft flight path without the implementation of the conventional aerodynamic flight controls (CAFC). TVFC can also be used to hold stationary flight in areas of the flight envelope where the main aerodynamic surfaces are stalled."Thrust Vectoring Nozzle for Modern Military Aircraft" Daniel Ikaza, ITP, presented at NATO R&T Organization Symposium, Braunschweig, Germany, 8–11 May 2000 TVFC includes control of
STOVL A short take-off and vertical landing aircraft (STOVL aircraft) is a fixed-wing aircraft that is able to take off from a short runway (or take off vertically if it does not have a heavy payload) and land vertically (i.e. with no runway). The ...
aircraft during the hover and during the transition between hover and forward speeds below 50 knots where aerodynamic surfaces are ineffective."F-35B Integrated Flight Propulsion Control Development" Walker, Wurth, Fuller, AIAA 2013-44243, AIAA Aviation, August 12–14, 2013, Los Angeles, CA 2013 International Powered Lift Conference" When vectored thrust control uses a single propelling jet, as with a single-engined aircraft, the ability to produce rolling moments may not be possible. An example is an afterburning supersonic nozzle where nozzle functions are throat area, exit area, pitch vectoring and yaw vectoring. These functions are controlled by four separate actuators. A simpler variant using only three actuators would not have independent exit area control. When TVFC is implemented to complement CAFC, agility and safety of the aircraft are maximized. Increased safety may occur in the event of malfunctioning CAFC as a result of battle damage. To implement TVFC a variety of nozzles both mechanical and fluidic may be applied. This includes convergent and convergent-divergent nozzles that may be fixed or geometrically variable. It also includes variable mechanisms within a fixed nozzle, such as rotating cascades and rotating exit vanes. Within these aircraft nozzles, the geometry itself may vary from two-dimensional (2-D) to axisymmetric or elliptic. The number of nozzles on a given aircraft to achieve TVFC can vary from one on a CTOL aircraft to a minimum of four in the case of STOVL aircraft.


Definitions

; Axisymmetric: Nozzles with circular exits. ; Conventional aerodynamic flight control (CAFC): Pitch, yaw-pitch, yaw-pitch-roll or any other combination of aircraft control through aerodynamic deflection using rudders, flaps, elevators and/or ailerons. ; Converging-diverging nozzle (C-D): Generally used on supersonic jet aircraft where nozzle pressure ratio (npr) > 3. The engine exhaust is expanded through a converging section to achieve Mach 1 and then expanded through a diverging section to achieve supersonic speed at the exit plane, or less at low npr."Nozzle Selection and Design Criteria" Gambell, Terrell, DeFrancesco, AIAA 2004-3923 ; Converging nozzle: Generally used on subsonic and transonic jet aircraft where npr < 3. The engine exhaust is expanded through a converging section to achieve Mach 1 at the exit plane, or less at low npr. ; Effective Vectoring Angle: The average angle of deflection of the jet stream centreline at any given moment in time. ; Fixed nozzle: A thrust-vectoring nozzle of invariant geometry or one of variant geometry maintaining a constant geometric area ratio, during vectoring. This will also be referred to as a civil aircraft nozzle and represents the nozzle thrust vectoring control applicable to passenger, transport, cargo and other subsonic aircraft. ; Fluidic thrust vectoring: The manipulation or control of the exhaust flow with the use of a secondary air source, typically bleed air from the engine compressor or fan."Experimental Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for Supersonic Aircraft application" Flamme, Deere, Mason, Berrier, Johnson, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070030933.pdf ; Geometric vectoring angle: Geometric centreline of the nozzle during vectoring. For those nozzles vectored at the geometric throat and beyond, this can differ considerably from the effective vectoring angle. ; Three-bearing swivel duct nozzle (3BSD): Three angled segments of engine exhaust duct rotate relative to one another about duct centreline to produce nozzle thrust axis pitch and yaw. ; Three-dimensional (3-D): Nozzles with multi-axis or pitch and yaw control. ; Thrust vectoring (TV): The deflection of the jet away from the body-axis through the implementation of a flexible nozzle, flaps, paddles, auxiliary fluid mechanics or similar methods. ; Thrust-vectoring flight control (TVFC): Pitch, yaw-pitch, yaw-pitch-roll, or any other combination of aircraft control through deflection of thrust generally issuing from an air-breathing turbofan engine. ; Two-dimensional (2-D): Nozzles with square or rectangular exits. In addition to the geometrical shape 2-D can also refer to the degree-of-freedom (DOF) controlled which is single axis, or pitch-only, in which case round nozzles are included. ; Two-dimensional converging-diverging (2-D C-D): Square, rectangular, or round supersonic nozzles on fighter aircraft with pitch-only control. ; Variable nozzle: A thrust-vectoring nozzle of variable geometry maintaining a constant, or allowing a variable, effective nozzle area ratio, during vectoring. This will also be referred to as a military aircraft nozzle as it represents the nozzle thrust vectoring control applicable to fighter and other supersonic aircraft with afterburning. The convergent section may be fully controlled with the divergent section following a pre-determined relationship to the convergent throat area. Alternatively, the throat area and the exit area may be controlled independently, to allow the divergent section to match the exact flight condition.


Methods of nozzle control

; Geometric area ratios: Maintaining a fixed geometric area ratio from the throat to the exit during vectoring. The effective throat is constricted as the vectoring angle increases. ; Effective area ratios: Maintaining a fixed effective area ratio from the throat to the exit during vectoring. The geometric throat is opened as the vectoring angle increases. ; Differential area ratios: Maximizing nozzle expansion efficiency generally through predicting the optimal effective area as a function of the mass flow rate.


Methods of thrust vectoring

; Type I: Nozzles whose baseframe mechanically is rotated before the geometrical throat. ; Type II: Nozzles whose baseframe is mechanically rotated at the geometrical throat. ; Type III: Nozzles whose baseframe is not rotated. Rather, the addition of mechanical deflection post-exit vanes or paddles enables jet deflection. ; Type IV: Jet deflection through counter-flowing or co-flowing (by shock-vector control or throat shifting) auxiliary jet streams. Fluid-based jet deflection using secondary fluidic injection. ; ''Additional type'': Nozzles whose upstream exhaust duct consists of wedge-shaped segments which rotate relative to each other about the duct centreline.


Operational examples


Aircraft

An example of 2D thrust vectoring is the
Rolls-Royce Pegasus The Rolls-Royce Pegasus is a British turbofan engine originally designed by Bristol Siddeley. It was manufactured by Rolls-Royce plc. The engine is not only able to power a jet aircraft forward, but also to direct thrust downwards via Thrust ve ...
engine used in the
Hawker Siddeley Harrier The Hawker Siddeley Harrier is a British jet-powered attack aircraft designed and produced by the British aerospace company Hawker Siddeley. It was the first operational ground attack and reconnaissance aircraft with vertical/short takeo ...
, as well as in the AV-8B Harrier II variant. Widespread use of thrust vectoring for enhanced maneuverability in Western production-model fighter aircraft didn't occur until the deployment of the
Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...
F-22 Raptor fifth-generation jet fighter in 2005, with its afterburning, 2D thrust-vectoring Pratt & Whitney F119
turbofan A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the add ...
."F-22 Raptor fact sheet."
''U.S. Air Force'', March 2009. Retrieved: 10 July 2014.
While the
Lockheed Martin F-35 Lightning II The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, supersonic Stealth aircraft, stealth strike fighters. A multirole combat aircraft designed for both Air superiority fighter, air superiority and att ...
uses a conventional afterburning turbofan (Pratt & Whitney F135) to facilitate supersonic operation, its F-35B variant, developed for joint usage by the US Marine Corps,
Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
,
Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
, and
Italian Navy The Italian Navy (; abbreviated as MM) is one of the four branches of Italian Armed Forces and was formed in 1946 from what remained of the ''Regia Marina'' (Royal Navy) after World War II. , the Italian Navy had a strength of 30,923 active per ...
, also incorporates a vertically mounted, low-pressure shaft-driven remote fan, which is driven through a clutch during landing from the engine. Both the exhaust from this fan and the main engine's fan are deflected by thrust vectoring nozzles, to provide the appropriate combination of lift and propulsive thrust. It is not conceived for enhanced maneuverability in combat, only for
VTOL A vertical take-off and landing (VTOL) aircraft is one that can takeoff and landing, take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust- ...
operation, and the F-35A and F-35C do not use thrust vectoring at all. The
Sukhoi Su-30MKI The Sukhoi Su-30MKI (NATO reporting name: Flanker-H) is a two-seater, twinjet Multirole combat aircraft, multirole air superiority fighter developed by Russian aircraft manufacturer Sukhoi and built under licence by India's Hindustan Aeronautic ...
, produced by India under licence at
Hindustan Aeronautics Limited Hindustan Aeronautics Limited (HAL) is an Indian public sector aerospace and defence company, headquartered in Bengaluru. Established on 23 December 1940, HAL is one of the oldest and largest aerospace and defence manufacturers in the world. H ...
, is in active service with the
Indian Air Force The Indian Air Force (IAF) (ISO 15919, ISO: ) is the air force, air arm of the Indian Armed Forces. Its primary mission is to secure Indian airspace and to conduct aerial warfare during armed conflicts. It was officially established on 8 Octob ...
. The TVC makes the aircraft highly maneuverable, capable of near-zero airspeed at high angles of attack without stalling, and dynamic aerobatics at low speeds. The
Su-30MKI The Sukhoi Su-30MKI (NATO reporting name: Flanker-H) is a two-seater, twinjet multirole air superiority fighter developed by Russian aircraft manufacturer Sukhoi and built under licence by India's Hindustan Aeronautics Limited (HAL) for th ...
is powered by two Al-31FP
afterburning An afterburner (or reheat in British English) is an additional combustion component used on some jet engines, mostly those on military aircraft, military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, ta ...
turbofan A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the add ...
s. The TVC nozzles of the MKI are mounted 32 degrees outward to longitudinal engine axis (i.e. in the horizontal plane) and can be deflected ±15 degrees in the vertical plane. This produces a corkscrew effect, greatly enhancing the turning capability of the aircraft. A few computerized studies add thrust vectoring to extant passenger airliners, like the Boeing 727 and 747, to prevent catastrophic failures, while the experimental X-48C may be jet-steered in the future.


Other

Examples of rockets and missiles which use thrust vectoring include both large systems such as the
Space Shuttle Solid Rocket Booster The Space Shuttle Solid Rocket Booster (SRB) was the first solid-propellant rocket to be used for primary propulsion on a vehicle used for human spaceflight. A pair of them provided 85% of the Space Shuttle's thrust at liftoff and for the first ...
(SRB), S-300P (SA-10)
surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground or the sea to destroy aircraft or other missiles. It is one type of anti-ai ...
,
UGM-27 Polaris The UGM-27 Polaris missile was a two-stage solid-fueled nuclear-armed submarine-launched ballistic missile (SLBM). As the United States Navy's first SLBM, it served from 1961 to 1980. In the mid-1950s the Navy was involved in the Jupiter missi ...
nuclear
ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typic ...
and RT-23 (SS-24) ballistic missile and smaller battlefield weapons such as Swingfire. The principles of air thrust vectoring have been recently adapted to military sea applications in the form of fast water-jet steering that provide super-agility. Examples are the fast patrol boat Dvora Mk-III, the Hamina class missile boat and the US Navy's Littoral combat ships.


List of vectored thrust aircraft

Thrust vectoring can convey two main benefits: VTOL/STOL, and higher maneuverability. Aircraft are usually optimized to maximally exploit one benefit, though will gain in the other.


For VTOL ability

* Bell Model 65 * Bell X-14 * Bell Boeing V-22 Osprey *
Boeing X-32 The Boeing X-32 is a concept demonstrator aircraft that was designed for the Joint Strike Fighter program, Joint Strike Fighter competition. It lost to the Lockheed Martin X-35 demonstrator, which was further developed into the Lockheed Martin ...
* Dornier Do 31 * EWR VJ 101 *
Harrier jump jet The Harrier, informally referred to as the Harrier jump jet, is a family of jet-powered attack aircraft capable of vertical/short takeoff and landing operations (V/STOL). Named after the bird of prey, it was originally developed by British ...
**
British Aerospace Harrier II The British Aerospace Harrier II is a second-generation vertical/short takeoff and landing (V/STOL) jet aircraft used previously by the Royal Air Force (RAF) and, between 2006 and 2010, the Royal Navy (RN). The aircraft was the latest developme ...
**
British Aerospace Sea Harrier The British Aerospace Sea Harrier is a naval short take-off and vertical landing/ vertical take-off and landing jet fighter, reconnaissance and attack aircraft. It is the second member of the Harrier family developed. It first entered serv ...
**
Hawker Siddeley Harrier The Hawker Siddeley Harrier is a British jet-powered attack aircraft designed and produced by the British aerospace company Hawker Siddeley. It was the first operational ground attack and reconnaissance aircraft with vertical/short takeo ...
**
McDonnell Douglas AV-8B Harrier II The McDonnell Douglas (now Boeing) AV-8B Harrier II is a single-engine ground-attack aircraft that constitutes the second generation of the Harrier family, capable of vertical or short takeoff and landing (V/STOL). The aircraft is primari ...
* Hawker Siddeley Kestrel * Hawker Siddeley P.1127 * Lockheed Martin F-35B Lightning II * VFW VAK 191B *
Yakovlev Yak-38 The Yakovlev Yak-38 (; NATO reporting name: "Forger") was Soviet Naval Aviation's only operational VTOL strike fighter aircraft in addition to being its first operational carrier-based fixed-wing aircraft. It was developed specifically for, and ...
* Yakovlev Yak-141


For higher maneuverability


Vectoring in two dimensions

* McDonnell Douglas F-15 STOL/MTD (experimental) *
Lockheed Martin F-22 Raptor The Lockheed Martin/Boeing F-22 Raptor is an American Twinjet, twin-engine, Jet engine, jet-powered, Night fighter, all-weather, supersonic Stealth aircraft, stealth fighter aircraft. As a product of the United States Air Force's Advanced Ta ...
(pitch only) *
Chengdu J-20 The Chengdu J-20 (), also known as Mighty Dragon (, NATO reporting name: Fagin), is a twinjet, twin-engine Night fighter, all-weather Stealth aircraft, stealth fighter developed by China's Chengdu Aircraft Corporation for the People's Liberatio ...
(earlier variants with WS-10C, pitch and roll) * McDonnell Douglas X-36 (yaw only) *
Boeing X-45A The Boeing X-45 unmanned combat air vehicle is a concept demonstrator for a "next generation" of completely autonomous military aircraft, developed by Boeing's Boeing Phantom Works, Phantom Works. Manufactured by Boeing Integrated Defense Systems ...
(yaw only) * Me 163 B experimentally used a rocket steering paddle for the yaw axis


Vectoring in three dimensions

* McDonnell Douglas F-15 ACTIVE (experimental) * Mitsubishi X-2 (experimental) * McDonnell Douglas F-18 HARV (experimental) * General Dynamics F-16 VISTA (experimental) * Rockwell-MBB X-31 (experimental) * Chengdu J-10B TVC testbed (experimental) * Mikoyan MiG-35 (MiG-29OVT, not in production aircraft) * Sukhoi Su-37 (demonstrator) *
Sukhoi Su-47 The Sukhoi Su-47 ''Berkut'' () (NATO reporting name Firkin), also designated S-32 and S-37 during initial development, was a Russian experimental supersonic fighter aircraft, jet fighter developed by the Sukhoi, JSC Sukhoi Company. A distingui ...
(experimental) * Sukhoi Su-57 *
Sukhoi Su-30MKI The Sukhoi Su-30MKI (NATO reporting name: Flanker-H) is a two-seater, twinjet Multirole combat aircraft, multirole air superiority fighter developed by Russian aircraft manufacturer Sukhoi and built under licence by India's Hindustan Aeronautic ...
/ MKM/ MKA/ SM (pitch and roll, with canted engine nozzles (for yaw), emulating but not direct 3D thrust vectoring) * Sukhoi Su-35S (roll and yaw, however engines are canted at an angle for pitch, providing 3D thrust vectoring; more advanced version than the SU-30MKI and derivatives)


For STOL ability

* Grumman YA2F-1 Intruder (First 7 examples)https://ntrs.nasa.gov/api/citations/19810016529/downloads/19810016529.pdf


Airships

*
23 class airship The 23 class were rigid airships produced in the United Kingdom during the First World War. Development of the 23 class began in August 1915 when Vickers was asked to improve the 9r design by increasing its gas capacity by adding a bay and in ...
, a series of British, World War 1 airships * Airship Industries Skyship 600 modern airship * Zeppelin NT modern, thrust–vectoring airship


Helicopters

* Sikorsky XV-2 * NOTAR


See also

*
Index of aviation articles Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Articles related to aviation include: A Aviation accidents and incidents – Above Mean Sea Level (AMSL) – ADF – Acces ...
*
Gimbaled thrust Gimbaled thrust is the system of thrust vectoring used in most rockets, including the Space Shuttle program, Space Shuttle, the Saturn V lunar rockets, and the Falcon 9. Operation In a gimbaled thrust system, the engine or just the exhaust nozz ...
*
Reverse thrust Reverse or reversing may refer to: Arts and media *Reverse (Eldritch album), ''Reverse'' (Eldritch album), 2001 *Reverse (2009 film), ''Reverse'' (2009 film), a Polish comedy-drama film *Reverse (2019 film), ''Reverse'' (2019 film), an Iranian cr ...
* Tiltjet *
Tiltrotor A tiltrotor is an aircraft that generates lift (force), lift and thrust, propulsion by way of one or more powered Helicopter rotor, rotors (sometimes called ''proprotors'') mounted on rotating shaft (mechanical engineering), shafts or nacelles ...
*
Tiltwing A tiltwing aircraft features a wing that is horizontal for conventional forward flight and rotates up for vertical takeoff and landing. It is similar to the tiltrotor design where only the propeller and engine rotate. Tiltwing aircraft are typic ...
*
Tail-sitter A tail-sitter, or tailsitter, is a type of VTOL aircraft that takes off and lands on its empennage, tail, then tilts horizontally for forward flight. Originating in the 1920s with the inventor Nikola Tesla, the first aircraft to adopt a tail-sit ...
*
VTOL A vertical take-off and landing (VTOL) aircraft is one that can takeoff and landing, take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust- ...


References

8. Wilson, Erich A., "An Introduction to Thrust-Vectored Aircraft Nozzles",


External links


Application of Thrust Vectoring to Reduce Vertical Tail Size

Supersonic STOVL Research Aircraft

NASA Technical Paper 1533 Longitudinal Aerodynamic Characteristics of a Vectored-Engine-Over-Wing Configuration at Subsonic Speeds
* {{Commons category-inline Jet engines Airship technology