Editing Thrust vectoring (section)

== Methods ==

=== Rockets and ballistic missiles ===
[[File:En Gimbaled thrust diagram.svg|thumb|[[torque|Moments]] generated by different thrust gimbal angles]]
[[File:Gimbaled thrust animation.gif|thumb|Animation of the motion of a rocket as the thrust is vectored by actuating the nozzle]]Nominally, the [[line of action]] of the thrust vector of a [[rocket nozzle]] passes through the vehicle's [[centre of mass]], generating zero net [[torque]] about the mass centre. It is possible to generate [[Aircraft principal axes#Principal axes|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 [[Aircraft principal axes#Longitudinal axis (roll)|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:<ref name="Sutton ">George P. Sutton, Oscar Biblarz, ''Rocket Propulsion Elements'', 7th Edition.</ref><ref>Michael D. Griffin and James R. French, ''Space Vehicle Design'', Second Edition.</ref>

* [[Gimbaled thrust|Gimbaled]] engine(s) or nozzle(s)
* Reactive fluid injection
* Auxiliary "Vernier" thrusters
* Exhaust vanes, also known as jet vanes

====Gimbaled thrust====
{{main|gimbaled thrust}}
Thrust vectoring for many [[liquid rocket]]s is achieved by [[gimbaled thrust|gimbal]]ing the whole [[rocket engine|engine]]. This involves moving the entire [[combustion chamber]] and outer engine bell as on the [[Titan II]]'s twin first-stage motors, or even the entire engine assembly including the related [[fuel pump|fuel]] and [[oxidizer]] pumps. The [[Saturn V]] and the [[Space Shuttle]] used gimbaled engines.<ref name="Sutton" />

A later method developed for [[solid rocket propellant|solid propellant]] [[ballistic missile]]s achieves thrust vectoring by deflecting only the [[rocket nozzle|nozzle]] of the rocket using electric actuators or [[hydraulic cylinder]]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]] and a higher power actuation system. The [[UGM-96 Trident I|Trident C4]] and [[UGM-133 Trident II|D5]] systems are controlled via hydraulically actuated nozzle. The [[Space Shuttle Solid Rocket Booster|STS SRB]]s used gimbaled nozzles.<ref name=RSRM-ALCS>{{cite journal |title=Reusable Solid Rocket Motor—Accomplishments, Lessons, and a Culture of Success |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001536.pdf |website=ntrs.nasa.gov |date=27 September 2011 |access-date=February 26, 2015 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304210207/http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001536.pdf |url-status=live }}</ref>

====Propellant injection====
Another method of thrust vectoring used on [[solid rocket propellant|solid propellant]] [[ballistic missile]]s is liquid injection, in which the [[rocket nozzle]] is fixed, however a fluid is introduced into the [[Exhaust gas#Jet engines and rocket engines|exhaust]] 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 [[LGM-30 Minuteman#Minuteman-II (LGM-30F)|Minuteman II]] and the early [[SLBM]]s of the [[United States Navy]].

====Vernier thrusters====
An effect similar to thrust vectoring can be produced with multiple [[vernier thruster]]s, small auxiliary combustion chambers which lack their own turbopumps and can gimbal on one axis. These were used on the [[Atlas missile|Atlas]] and [[R-7 (rocket family)|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]] thrusters, which are fixed and independent rocket engines used for maneuvering in space.

====Exhaust vanes====
[[File:Antwerp V-2.jpg|thumb|Graphite exhaust vanes on a V-2 rocket engine's nozzle]]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 rocket|V-2]] used graphite exhaust vanes and aerodynamic vanes, as did the [[PGM-11 Redstone|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]]s, such as the [[AIM-9 Sidewinder#AIM-9X|AIM-9X Sidewinder]], eschew [[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 (missile)|Eryx]] and the [[PARS 3 LR]] use thrust vectoring for this reason.<ref name="thefreelibrary.com">{{cite web|url=http://www.thefreelibrary.com/Anti-tank+guided+missile+developments.-a09046203|access-date=2014-03-27|title=Anti-tank guided missile developments|archive-date=2012-10-16|archive-url=https://web.archive.org/web/20121016153120/http://www.thefreelibrary.com/Anti-tank+guided+missile+developments.-a09046203|url-status=live}}</ref>

Some other projectiles that use thrust-vectoring:
* [[Tor missile system|9M330]]<ref>{{cite web|url=http://en.uos.ua/produktsiya/tehnika-pvo/69-boevaya-mashina-tor-9a330|access-date=2014-03-27|title=Combat Vehicle Tor 9A330|publisher=State company "UKROBORONSERVICE"|archive-date=2015-03-31|archive-url=https://web.archive.org/web/20150331112119/http://en.uos.ua/produktsiya/tehnika-pvo/69-boevaya-mashina-tor-9a330|url-status=live}}</ref>
* [[Strix mortar round]] uses twelve midsection lateral thruster rockets to provide terminal course corrections<ref name="thefreelibrary.com"/>
*[[Indian Ballistic Missile Defence Programme#Advanced Air Defence (AAD)|Advanced Air Defence]] missile uses jet vanes
* [[Astra (missile)]]<ref>{{cite news|title=First test of air-to-air missile Astra Mk II likely on February 18|url=https://www.newindianexpress.com/states/odisha/2021/feb/17/first-test-of-air-to-air-missile-astra-mk-ii-likely-on-feb-18-2265176.html|access-date=2021-05-30|archive-date=2021-06-02|archive-url=https://web.archive.org/web/20210602212858/https://www.newindianexpress.com/states/odisha/2021/feb/17/first-test-of-air-to-air-missile-astra-mk-ii-likely-on-feb-18-2265176.html|url-status=live}}</ref>
* [[Akash (missile)]]<ref>{{cite news|title=Akash Surface-to-Air Missile (SAM) System-Airforce Technology|url=https://www.airforce-technology.com/projects/akash-surface-to-air-missile-system/|access-date=2021-05-30|archive-date=2021-03-05|archive-url=https://web.archive.org/web/20210305080732/https://www.airforce-technology.com/projects/akash-surface-to-air-missile-system/|url-status=live}}</ref>
* [[BrahMos]]<ref>{{cite news|title=Explained: From Pinaka to Astra, the new weapons DAC has approved 'for defence of borders'|url=https://indianexpress.com/article/explained/astra-missile-pinaka-air-to-air-iaf-drdo6487261/|access-date=2021-05-30|archive-date=2021-06-02|archive-url=https://web.archive.org/web/20210602214702/https://indianexpress.com/article/explained/astra-missile-pinaka-air-to-air-iaf-drdo6487261/|url-status=live}}</ref>
* [[MPATGM]] uses jet vanes
* [[Pralay (missile)|Pralay]] uses jet vanes
* [[QRSAM]] uses jet vanes
* [[NASM-SR]] uses jet vanes<ref>{{Cite web |last=Singh |first=Mayank |date=2025-02-26 |title=Indian Navy successfully tests first-of-its-kind NASM-SR missile with in-flight retargeting |url=https://www.newindianexpress.com/nation/2025/Feb/26/indian-navy-successfully-tests-first-of-its-kind-nasm-sr-missile-with-in-flight-retargeting |access-date=2025-02-26 |website=The New Indian Express |language=en}}</ref>
* [[AAM-5 (Japanese missile)|AAM-5]]
* [[Barak 8]] uses jet vanes
* [[A-Darter]] uses jet vanes
* [[ASRAAM]] uses jet vanes
* [[R-73 (missile)]] uses jet vanes
* [[HQ-9]] uses jet vanes
* [[PL-10 (ASR)]] uses jet vanes
* [[MICA (missile)]] uses jet vanes
* [[PARS 3 LR]] uses jet vanes
* [[IRIS-T]]
* [[Aster (missile family)|Aster missile family]] combines aerodynamic control and the direct thrust vector control called "PIF-PAF"
* [[AIM-9 Sidewinder#AIM-9X|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.<ref>{{cite web|url=https://www.fas.org/nuke/guide/russia/airdef/s-400.htm|access-date=2014-03-27|title=S-400 SA-20 Triumf|publisher=Federation of American Scientists|archive-date=2013-12-05|archive-url=https://web.archive.org/web/20131205033630/http://www.fas.org/nuke/guide/russia/airdef/s-400.htm|url-status=live}}</ref>
* [[9K720 Iskander]] is controlled during the whole flight with gas-dynamic and aerodynamic control surfaces.
* [[Dongfeng (missile)|Dongfeng]] subclasses/[[JL-2]]/[[JL-3]] ballistic missiles (allegedly fitted with TVC control) <ref>{{Cite web |title=China's ballistic missile industry |url=https://airuniversity.af.edu/Portals/10/CASI/documents/Research/PLARF/2021-05-11%20Ballistic%20Missile%20Industry.pdf?ver=Y3oJa8Z9eK2rpAO9tQGCcQ%3D%3D |access-date=2022-03-16 |archive-date=2022-03-07 |archive-url=https://web.archive.org/web/20220307222912/https://www.airuniversity.af.edu/Portals/10/CASI/documents/Research/PLARF/2021-05-11%20Ballistic%20Missile%20Industry.pdf?ver=Y3oJa8Z9eK2rpAO9tQGCcQ%3d%3d |url-status=live }}</ref>

=== Aircraft ===
[[File:Bell_Boeing_MV-22_Osprey_line_drawing.svg|alt=Drawing of an airplane with rotors arranged traditionally, vertically, and with rotors arranged horizontally like in helicopters.|thumb|Tiltrotor of the V-22 Osprey. The engines rotate 90° after takeoff.]]
Most currently operational vectored thrust aircraft use [[turbofan]]s with rotating [[nozzle]]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]] (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]] aircraft vector thrust via rotating [[turboprop]] engine [[nacelle]]s. The mechanical complexities of this design are quite troublesome, including twisting flexible internal components and [[driveshaft]] 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.

[[File:Airship Delta.jpg|thumb|The pre-World War 1, British Army airship ''Delta'', fitted with swiveling propellers]]

Thrust vectoring is also used as a control mechanism for [[airship]]s. An early application was the British Army airship ''Delta'', which first flew in 1912.<ref>{{cite book |last= Mowthorpe |first= Ces |title= Battlebags: British Airships of the First World War |page=11|publisher= Wrens Park |year= 1998|isbn= 0-905778-13-8}}</ref> It was later used on HMA (His Majesty's Airship) [[No. 9r]], a British rigid airship that first flew in 1916<ref>
{{cite book |last= Abbott |first= Patrick |title=The British Airship at War |page=84|publisher= Terence Dalton |year= 1989|isbn= 0-86138-073-8}}
</ref> and the twin 1930s-era U.S. Navy rigid airships [[USS Akron (ZRS-4)|USS ''Akron'']] and [[USS Macon (ZRS-5)|USS ''Macon'']] that were used as [[airborne aircraft carrier]]s, and a similar form of thrust vectoring is also particularly valuable today for the control of modern [[non-rigid airship]]s. In this use, most of the load is usually supported by [[buoyancy]] 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.<ref>{{cite web|url=http://www.diomedia.com/public/en/18094603/imageDetails.html|title=STOCK IMAGE - A 1949 jet deflection vectored-thrust propulsion concept by www.DIOMEDIA.com|website=Diomedia|access-date=2014-11-18|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304034645/http://www.diomedia.com/public/en/18094603/imageDetails.html|url-status=live}}</ref> Official interest was curtailed when it was realised that the designer was a patient in a mental hospital.{{citation needed|reason=An account has reputedly been published in the (British) National Aerospace Library newsletter, which is subscription-only so can someone verify this reference?|date=November 2014}}

Now being researched, Fluidic Thrust Vectoring (FTV) diverts thrust via secondary [[fluidics|fluidic]] injections.<ref>{{cite journal
 |author=P. J. Yagle
 |author2=D. N. Miller
 |author3=K. B. Ginn
 |author4=J. W. Hamstra
 |title=Demonstration of Fluidic Throat Skewing for Thrust Vectoring in Structurally Fixed Nozzles
 |journal=Journal of Engineering for Gas Turbines and Power
 |volume=123
 |issue=3
 |pages=502–508
 |year=2001
 |doi=10.1115/1.1361109
 |url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000123000003000502000001
 |access-date=2007-03-18
 |archive-date=2020-01-26
 |archive-url=https://web.archive.org/web/20200126062022/http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000123000003000502000001
 |url-status=live
 |url-access=subscription
 }}</ref> 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]] (for faster, stronger control response), complexity (mechanically simpler, fewer or no moving parts or surfaces, less maintenance), and [[radar cross section]] for [[stealth technology|stealth]]. This will likely be used in many [[unmanned aerial vehicle]] (UAVs), and 6th generation [[fighter aircraft]].