Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust or changing of propeller pitch so that the thrust produced is directed forward, rather than aft. An aircraft engine is a Propulsion system for an Aircraft. Aircraft engines are almost always a type of lightweight Internal combustion engine. This acts against the forward travel of the aircraft, providing deceleration. Thrust reversers are used by many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. A jet aircraft is an Aircraft propelled by Jet engines Jet aircraft fly much faster than Propeller -powered aircraft and at higher altitudes -- as high as It is also available on many propeller aircraft through reversing the controllable pitch propellers to a negative angle. A propeller is essentially a type of fan which transmits power by converting Rotational motion into Thrust for propulsion of a vehicle such as an A controllable pitch propeller (CPP or variable pitch propeller is a special type of Propeller with blades that can be rotated around their long axis to change their
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Operation
Reverse thrust is typically applied immediately after touchdown, often along with spoilers, to improve deceleration early in the landing roll when residual aerodynamic lift and high speed limit the effectiveness of the friction brakes located on the landing gear. TurboJET (噴射飛航 is the brand name for the operations of the Hong Kong -based Shun Tak-China Travel Ship Management Limited (信德中旅船務管理有限公司 WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout Munich Airport, officially named Franz Josef Strauss Airport ( Flughafen München Franz Josef Strauß) is located northeast of Munich, Germany In Aeronautics a spoiler (sometimes called a lift dumper) is a device intended to reduce lift in an aircraft In the context of a Fluid flow relative to a body the lift force is the component of the Aerodynamic force that is Perpendicular to the flow A brake is a device for slowing or stopping the motion of a Machine or Vehicle, or alternatively a device to restrain it from starting to move again In Aviation, the undercarriage or landing gear is the structure (usually wheels that supports an Aircraft on the ground and allows it to taxi Reverse thrust is always selected manually, either using levers attached to the thrust levers, or by moving the thrust levers into a reverse thrust 'gate'. When thrust is reversed, passengers will hear a sudden increase in engine noise, particularly those seated just forward of the engines.
The early deceleration reverse thrust provides can reduce landing roll by a third or more. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout A turbofan is a type of Jet engine, similar to a Turbojet. It essentially consists of a Ducted fan with a smaller diameter turbojet engine Aloha Airlines was an American airline headquartered in Honolulu, Hawaii, USA, operating from a hub at Honolulu International WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout Honolulu is the Capital and most populous Census-designated place (CDP in the U The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the Regulations dictate, however, that a plane must be able to land on a runway without the use of thrust reversers in order to be certified to land there as part of scheduled airline service. An airline provides air transport services for Passengers or Freight, generally with a recognized operating certificate or license
Once the aircraft's speed has slowed, thrust reverse is shut down to prevent the reversed airflow from raising debris in front of the engine intakes where it can be ingested, causing foreign object damage. Thrust reverse is effective at any aircraft speed, and, if circumstances require, can be used all the way to a stop, or even to provide thrust to push the aircraft backward, though aircraft tugs or towbars are more commonly used for that purpose. In Aviation, pushback is an Airport procedure during which an Aircraft is pushed backwards away from an Airport gate by external A tow hitch (or tow bar) is a device attached to the Chassis of a vehicle for Towing or a towbar to an Aircraft nose gear or paired main gears
If the full power of reverse thrust is not desirable, thrust reverse can be operated with the throttles set at less than full power, even down to idle power, which reduces stress and wear on engine components. Reverse thrust is sometimes selected on idling engines to eliminate residual thrust, particularly in icy or slippery conditions, or where the engines' jet blast could do damage. Jet blast is the phenomenon of rapid air movement produced by the jet Engines of Aircraft, particularly on or before takeoff
In-flight operation
Some aircraft are able to safely use reverse thrust in flight, though the majority of these are propeller-driven. The radial engine is a reciprocating type internal combustion Engine configuration in which the cylinders point outward from a central WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout A flying boat is a specialised form of Aircraft that is designed to take off from and land on water using its Fuselage as a floating hull. Minnesota Department of Natural Resources is the agency of the state of Minnesota charged with conserving and managing the state's natural resources In-flight use of reverse thrust has several advantages: It allows for rapid deceleration, enabling quick changes of speed; it also prevents the speed buildup normally associated with steep dives, allowing for rapid loss of altitude, which can be especially useful in hostile environments such as combat zones, and when making steep approaches to land.
For example, the ATR 72 turboprop can reverse thrust in flight, should the appropriate control lock be withdrawn. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The Hawker Siddeley Trident, a 120-180 seat airliner, was capable of descending at up to 10,000 ft/min (3,050 m/min) by use of the thrust reversers, though this capability was rarely used. The Trident, model DH121 or HS121, was a British short/medium-range three-engined Airliner designed by De Havilland The US Air Force's C-17A is one of the few modern aircraft that uses reverse thrust in flight. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The Boeing-manufactured aircraft is capable of in-flight deployment of reverse thrust on all four engines to facilitate steep tactical descents up to 15,000 ft/min (4,600 m/min) into combat environments. The Boeing Company is a major Aerospace and defense corporation originally founded by William E The Saab 37 Viggen (retired in November 2005) also had the ability to use reverse thrust before landing, enabling the use of many roads constructed in Sweden to double as wartime runways. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout
The Shuttle Training Aircraft, a highly modified Grumman Gulfstream II, uses reverse thrust in flight to help simulate the Space Shuttle aerodynamics so astronauts can practice landings. The Shuttle Training Aircraft (STA is a NASA training vehicle that duplicates the Space Shuttle 's approach profile and handling qualities allowing WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout NASA 's Space Shuttle, officially called the Space Transportation System ( STS) is the Spacecraft currently used by the United States
Types of aircraft
Small aircraft typically do not feature reverse thrust, except in specialized applications. Conversely, large aircraft (weighing more than 12,500 lb) almost always have the ability to reverse thrust. Both reciprocating engine and turboprop aircraft can have reverse thrust, and almost all propeller aircraft with reverse thrust have the ability to set the propeller angle to flat pitch (called Beta range) which generates no forward or reverse thrust, but provides large amounts of drag. A reciprocating engine, also often known as a piston engine, is a Heat engine that uses one or more reciprocating Pistons to convert A turboprop engine is a type of aircraft powerplant that uses a Gas turbine engine to drive a Propeller. This is especially useful in aircraft with complex reciprocating or turbine engines, as it enables engine speed to be kept high as the aircraft descends, avoiding doing damage to the engines by shock cooling them. Shock cooling refers to the theory that damage to engines (particularly air-cooled aviation piston engines) may occur because of an excessively rapid decrease in Temperature
Propeller aircraft
Propeller aircraft generate reverse thrust by changing the angle of their controllable pitch propellers so that the propellers direct their thrust forward, instead of aft as normal. A controllable pitch propeller (CPP or variable pitch propeller is a special type of Propeller with blades that can be rotated around their long axis to change their A turboprop engine is a type of aircraft powerplant that uses a Gas turbine engine to drive a Propeller. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout A propeller is essentially a type of fan which transmits power by converting Rotational motion into Thrust for propulsion of a vehicle such as an A controllable pitch propeller (CPP or variable pitch propeller is a special type of Propeller with blades that can be rotated around their long axis to change their Reverse thrust has been available on propeller aircraft dating back to the 1930s. Reverse thrust became available due to the development of controllable-pitch propellers, which change the angle of the propeller blades to make efficient use of engine power over a wide range of conditions.
Multiengine
Early multiengine aircraft such as the Boeing 247 and Douglas DC-2 were among the first to feature reverse thrust. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The Douglas DC-2 was a 14 seat twin-propeller Airliner produced by the Douglas Aircraft Corporation starting in 1934. As piston aircraft became heavier and more complex, reverse thrust became more important to allow them to operate from airports originally configured to handle the smaller planes of previous years. Additionally, the higher performance and greater altitude attainable by post World War II piston aircraft like the Lockheed Constellation made the ability to use flat pitch, or, in extreme cases, reverse thrust, in order to descend and slow for landing without overcooling the engines or approaching the runway with excessive speed. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout Finally, the advent of turboprops like the Vickers Viscount and Lockheed Electra brought even higher speeds and cruising altitudes to the fleet, as well as increased power that could be used both for improved performance and to provide reverse thrust. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout In Physics, power (symbol P) is the rate at which work is performed or energy is transmitted or the amount of energy required or expended for
Single-engine
Single-engine aircraft tend to be of such limited size that the weight and complexity of reverse thrust is unwarranted. However, large single-engine aircraft like the Cessna Caravan do have reverse thrust available, and single-engine seaplanes and flying boats tend to have reverse thrust as well. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout In other respects, reverse thrust on single-engine aircraft works much like that on other propeller aircraft.
Seaplanes and flying boats
One special application of reverse thrust comes in its use on seaplanes and flying boats. A seaplane is a Fixed-wing aircraft capable of taking off and landing (alighting on water A flying boat is a specialised form of Aircraft that is designed to take off from and land on water using its Fuselage as a floating hull. These aircraft, when landing on water, have no conventional braking method and must rely on slaloming and/or reverse thrust, as well as the drag of the water in order to slow or stop. Additionally, reverse thrust is often necessary for maneuvering on the water, where it is used to make tight turns or even back the aircraft, such as when leaving a dock or beach.
Jet aircraft
On aircraft using jet engines, thrust reversal is accomplished by causing the jet blast to flow forward rather than aft. specific --->A jet engine is a Reaction engine that discharges a fast moving jet of Fluid to Jet blast is the phenomenon of rapid air movement produced by the jet Engines of Aircraft, particularly on or before takeoff The engine does not run or rotate in reverse; Instead, thrust reversers are used to block the blast and redirect it forward. Two methods are commonly used: In the target-type thrust reverser, the reverser blades angle outward, giving the general appearance of flower petals, and forcing engine thrust to flow forward. In the clamshell type, two reverser buckets are hinged so that when they deploy, they intrude into the exhaust of the engine, capturing and reorienting the jet blast. This type of reverser is usually clearly visible at the rear of the engine during use.
Turbofan
In addition to the two types used on turbojet and low-bypass turbofan engines, a third type of thrust reverser is found on some high-bypass turbofan engines. A turbofan is a type of Jet engine, similar to a Turbojet. It essentially consists of a Ducted fan with a smaller diameter turbojet engine Doors in the bypass duct are used to redirect the air that has been accelerated by the engine's fan section but has not passed through the combustion chamber (called bypass air) so that it provides reverse thrust. A bypass duct is an Annular passage that allows some of a turbofan's airflow to bypass the Engine core or Gas generator The Boeing C-17 has a rare form of the above type in which even the exhaust from the core is redirected along with the main fan's air. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout This gives the C-17 unrivaled stopping ability among large jet powered aircraft.
Thrust-reverse related accidents
In-flight deployment of thrust reversers on aircraft not having that function as a design feature has directly contributed to the crashes of several transport-type aircraft:
- On 9 February 1982, Japan Airlines Flight 350 crashed 1,000 feet (300 m) short of the runway at Tokyo Haneda Airport following the intentional deployment of reverse thrust on two of the DC-8's four engines in an apparent suicide attempt, resulting in 24 passenger deaths. EasyJet Airline Company Limited, styled as easyJet, is a low cost airline based at London Luton Airport. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout Events 474 - Zeno crowned as co-emperor of the Byzantine Empire. Year 1982 ( MCMLXXXII) was a Common year starting on Friday (link displays the 1982 Gregorian calendar) Japan Airlines Flight 350 was a McDonnell Douglas DC-8-61, Aircraft registration, on a domestic scheduled passenger flight from Fukuoka, Japan located in Ōta Tokyo, Japan, is one of the two primary Airports serving the Greater Tokyo Area. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout
- On August 29, 1990, a Lockheed C-5A crashed shortly after take-off from Ramstein Air Base in Germany. Events 708 - Copper coins are minted in Japan for the first time (Traditional Japanese date: August 10, 708) Year 1990 ( MCMXC) was a Common year starting on Monday (link displays the 1990 Gregorian calendar) WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout Ramstein Air Base is a United States Air Force base in the German state of Rheinland-Pfalz. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. As the aircraft started to climb off the runway, one of the thrust reversers suddenly deployed. This resulted in loss of control of the aircraft and the subsequent crash. Of the 17 people on board, only 4 survived the crash.
- On 26 May 1991, Lauda Air Flight NG004. Events 451 - The Battle of Avarayr between Armenian rebels and the Sassanid Empire takes place Year 1991 ( MCMXCI) was a Common year starting on Tuesday (link will display full calendar of the Gregorian Calendar. Lauda Air Flight 004 was an international passenger flight that crashed due to a Thrust reverser deployment of the number 1 Engine, in flight The Boeing 767-300 aircraft suffered an uncommanded deployment of the No. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout 1 thrust reverser, which caused the airliner to stall and crash. [1] All 213 passengers and 10 crew were killed.
- On October 31, 1996, TAM Linhas Aéreas Flight 402. Events 445 BC – Ezra reads the Book of the Law to the Israelites in Jerusalem (see Nehemiah 91 NLTse Year 1996 ( MCMXCVI) was a Leap year starting on Monday (link will display full 1996 Gregorian calendar) TAM Transportes Aéreos Regionais Flight 402 was a scheduled domestic flight from Congonhas/São Paulo International Airport in São Paulo, Brazil The Fokker 100 crashed shortly after take-off from Congonhas/São Paulo International Airport, São Paulo, Brazil, striking an apartment building and several houses. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout São Paulo ( is the largest city in Brazil, with its metropolitan area ranking among the largest urban areas in the world |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld All 90 passengers and 6 crew members on board died. Three people were killed on the ground. The crash was attributed to the uncommanded deployment of a faulty thrust-reverser on the right engine shortly after take-off.
At least one accident has been blamed in part on late deployment of reverse thrust:
- On 8 December 2005, Southwest Airlines Flight 1248 overran the runway at Chicago Midway Airport, killing a 6-year old boy in a car. Events 1609 - Biblioteca Ambrosiana opens its reading room the second public library of Europe. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Southwest Airlines Flight 1248 (WN1248 SWA1248 was a scheduled passenger flight from Baltimore-Washington International Airport to Chicago Midway International Airport Chicago Midway International Airport, also known simply as Midway Airport or Midway, is an Airport in Chicago Illinois, United States It was confirmed in the official crash report that delayed reverse thrust played a role.
Gallery
 An Air Canada Boeing 777 with thrust reversers deployed, visible as a "split" in the engine nacelle |  Thrust reverser (clamshell-type) on a Rolls-Royce RB199 jet engine |  Controllable pitch propeller on the singe-turboprop of a FedEx Cessna 208B Grand Caravan |  KLM Fokker 100 landing with reverse-thrust buckets deployed. Air Canada () is Canada 's largest Airline and Flag carrier. The airline founded in 1937 has had its corporate headquarters in Montreal WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout A controllable pitch propeller (CPP or variable pitch propeller is a special type of Propeller with blades that can be rotated around their long axis to change their A turboprop engine is a type of aircraft powerplant that uses a Gas turbine engine to drive a Propeller. FedEx Corporation ( is a Logistics services company based in the United States. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout KLM Royal Dutch Airlines ( Dutch: Koninklijke Luchtvaart Maatschappij, literally Royal Aviation Company; usual English translation WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout |
References
- ^ 26 May 1991 - Lauda 004. Tailstrike. com: Cockpit Voice Recorder Database (2004-09-23). A Cockpit Voice Recorder (CVR is a Flight recorder used to record the audio environment in the flightdeck of an aircraft for the purpose of investigation of accidents and incidents "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1122 - Concordat of Worms. 1459 - Battle of Blore Heath, the first major battle of the English Retrieved on 2006-12-14. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1287 - St Lucia's flood: The Zuider Zee sea wall in the Netherlands collapses killing over 50000 people
External links
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