A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a

runway According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concre ...

. This classification can include a variety of types of aircraft including

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

s as well as

thrust-vectoring Thrust vectoring, also known as thrust vector control (TVC), is the ability of an aircraft, rocket, or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) to control the attitude or angular velocity of the ...

fixed-wing aircraft and other hybrid aircraft with powered

rotor Rotor may refer to: Science and technology Engineering * Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator *Helicopter rotor, the rotary wing(s) of a rotorcraft ...

s such as cyclogyros/cyclocopters and

gyrodyne A gyrodyne is a type of VTOL aircraft with a helicopter rotor-like system that is driven by its engine for takeoff and landing only, and includes one or more conventional propeller or jet engines to provide forward thrust during cruising flig ...

s. Some VTOL aircraft can operate in other modes as well, such as

CTOL A conventional take-off and landing (CTOL), also known as horizontal take-off and landing (HTOL) is the process whereby conventional fixed-wing aircraft (such as passenger aircraft) take off and land, involving the use of runways. During takeoff ...

(conventional take-off & landing), STOL (short take-off & landing), or

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 ...

(short take-off & vertical landing). Others, such as some helicopters, can only operate as VTOL, due to the aircraft lacking

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...

that can handle

taxiing Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircr ...

. VTOL is a subset of

V/STOL A vertical and/or short take-off and landing (V/STOL) aircraft is an airplane able to take-off or land vertically or on short runways. Vertical takeoff and landing (VTOL) aircraft are a subset of V/STOL craft that do not require runways at a ...

(vertical or short take-off & landing). Some lighter-than-air aircraft also qualify as VTOL aircraft, as they can hover, takeoff and land with vertical approach/departure profiles. Electric vertical takeoff and landing aircraft, or

eVTOL An electric vertical take-off and landing (eVTOL) aircraft is a variety of VTOL (vertical take-off and landing) aircraft that uses electric power to hover, take off, and land vertically. This technology came about thanks to major advances in elec ...

s, are being developed along with more autonomous flight control technologies and mobility-as-a-service (MaaS) to enable advanced air mobility (AAM), that could include on-demand air taxi services, regional air mobility, freight delivery, and

personal air vehicles A personal air vehicle (PAV) is a proposed type of aircraft providing on-demand aviation services. The emergence of this alternative to traditional ground transport methods has been enabled by unmanned aerial vehicle technologies and electric pr ...

(PAVs). Besides the ubiquitous helicopters, there are currently two types of VTOL aircraft in military service:

tiltrotor A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a trans ...

aircraft, such as the

Bell Boeing V-22 Osprey The Bell Boeing V-22 Osprey is an American multi-mission, tiltrotor military aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed to combine the functionality of a conventio ...

, and thrust-vectoring airplanes, such as the Harrier family and new

F-35B Lightning II The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather stealth multirole combat aircraft that is intended to perform both air superiority and strike missions. It is also able to provide elect ...

Joint Strike Fighter Joint Strike Fighter (JSF) is a development and acquisition program intended to replace a wide range of existing fighter, strike, and ground attack aircraft for the United States, the United Kingdom, Italy, Canada, Australia, the Netherlands ...

(JSF). In the civilian sector currently only helicopters are in general use (some other types of commercial VTOL aircraft have been proposed and are under development ). Generally speaking, VTOL aircraft capable of STOVL use it wherever possible, since it typically significantly increases takeoff weight, range or payload compared to pure VTOL.

History

Props, proprotors and advanced rotorcraft

The idea of vertical flight has been around for thousands of years, and sketches for a VTOL (helicopter) show up in

Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, Drawing, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially res ...

's sketch book. Manned VTOL aircraft, in the form of primitive helicopters, first flew in 1907 but would take until after World War Two to perfect. In addition to

development, many approaches have been tried to develop practical aircraft with vertical take-off and landing capabilities including

Henry Berliner Henry Adler Berliner (December 13, 1895 – May 1, 1970) was a United States aircraft and helicopter pioneer. Sixth son of inventor Emile Berliner, he was born in Washington, D.C. He studied mechanical engineering at Cornell University for two ...

's 1922–1925 experimental horizontal rotor fixed wing aircraft, and

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''

In the late 1930s British aircraft designer Leslie Everett Baynes was issued a patent for the

Baynes Heliplane Baynes is a surname. Notable people with the surname include: * Adam Baynes, English politician * Aron Baynes (born 1986), New Zealand-born Australian basketball player * Helton Godwin Baynes, (1882–1943), analytical psychologist, author, transl ...

, another tilt rotor aircraft. In 1941 German designer

Heinrich Focke Henrich Focke (8 October 1890 – 25 February 1979) was a German aviation pioneer from Bremen and also a co-founder of the Focke-Wulf company. He is best known as the inventor of the Fw 61, the first successful German helicopter. Biography ...

's began work on the

Focke-Achgelis Fa 269 The Focke-Achgelis Fa 269 was a tiltrotor VTOL aircraft project designed by Henrich Focke. Development Conceived as a single-seat fighter, the Fa 269 project resulted from a design study order issued by the Reich Air Ministry to Focke-Achgeli ...

, which had two rotors that tilted downward for vertical takeoff, but wartime bombing halted development. Convair XFY-1 Pogo 2

In May 1951, both Lockheed and

Convair Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953, i ...

were awarded contracts in the attempt to design, construct, and test two experimental VTOL fighters. Lockheed produced the XFV, and Convair producing the Convair XFY Pogo. Both experimental programs proceeded to flight status and completed test flights 1954–1955, when the contracts were cancelled. Similarly, the

Ryan X-13 Vertijet The Ryan X-13 Vertijet (company designation Model 69) was an experimental vertical take-off and landing (VTOL) jet aircraft built by Ryan Aeronautical and flown in the United States in the 1950s. The main objective of the project was to demons ...

flew a series of test flights between 1955 and 1957, but also suffered the same fate. The use of vertical fans driven by engines was investigated in the 1950s. The US built an aircraft where the jet exhaust drove the fans, while British projects not built included fans driven by mechanical drives from the jet engines. Xv-15 inflight

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

has flown other VTOL craft such as the Bell XV-15 research craft (1977), as have the Soviet Navy and ''

Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...

''. Sikorsky tested an aircraft dubbed the

X-Wing The X-wing starfighter is a name applied to a family of fictional spacecraft manufactured by the Incom Corporation from the ''Star Wars'' franchise. Named for the distinctive shape made when its s-foils (wings) are in attack position, the X-win ...

, which took off in the manner of a helicopter. The rotors would become stationary in mid-flight, and function as wings, providing lift in addition to the static wings.

Boeing X-50 The Boeing X-50A Dragonfly, formerly known as the Canard Rotor/Wing Demonstrator, was a VTOL rotor wing experimental unmanned aerial vehicle that was developed by Boeing and DARPA to demonstrate the principle that a helicopter's rotor could be st ...

is a Canard Rotor/Wing prototype that utilizes a similar concept. Fairey Jet Gyrodyne-1

A different British VTOL project was the

, where a rotor is powered during take-off and landing but which then freewheels during flight, with separate propulsion engines providing forward thrust. Starting with the Fairey Gyrodyne, this type of aircraft later evolved into the much larger twin-engined

Fairey Rotodyne The Fairey Rotodyne was a 1950s British compound gyroplane designed and built by Fairey Aviation and intended for commercial and military uses.tipjet A tip jet is a jet nozzle at the tip of some helicopter rotor blades, used to spin the rotor, much like a Catherine wheel firework. Tip jets replace the normal shaft drive and have the advantage of placing no torque on the airframe, thus not re ...

s to power the rotor on take-off and landing but which then used two

Napier Eland The Napier Eland was a British turboshaft or turboprop gas-turbine engine built by Napier & Son in the early 1950s. Production of the Eland ceased in 1961 when the Napier company was taken over by Rolls-Royce. Design and development The Elan ...

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. ...

s driving conventional propellers mounted on substantial wings to provide propulsion, the wings serving to unload the rotor during horizontal flight. The Rotodyne was developed to combine the efficiency of a fixed-wing aircraft at cruise with the VTOL capability of a helicopter to provide short haul airliner service from city centres to airports.

The CL-84 Dynavert was a Canadian

turbine tilt-wing monoplane designed and manufactured by Canadair between 1964 and 1972. The Canadian government ordered three updated CL-84s for military evaluation in 1968, designated the CL-84-1. From 1972 to 1974, this version was demonstrated and evaluated in the United States aboard the aircraft carriers USS ''Guam'' and USS ''Guadalcanal'', and at various other centres. These trials involved military pilots from the United States, the United Kingdom and Canada. During testing, two of the CL-84s crashed due to mechanical failures, but no loss of life occurred as a result of these accidents. No production contracts resulted. Although tiltrotors such as the

of the mid-1940s and the Centro Técnico Aeroespacial "Convertiplano" of the 1950s reached testing or mock-up stages, the

Bell-Boeing V-22 Osprey The Bell Boeing V-22 Osprey is an American multi-mission, tiltrotor military aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed to combine the functionality of a convention ...

is considered the world's first production

aircraft. It has one three-bladed

proprotor A proprotor is a spinning airfoil that function as both an airplane-style propeller and a helicopter-style rotor. Several proprotor-equipped convertiplanes, such as the Bell Boeing V-22 Osprey tiltrotor, are capable of switching back and forth betw ...

engine, and transmission

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

mounted on each wingtip. The Osprey is a multi-mission aircraft with both a vertical takeoff and landing (VTOL) and short takeoff and landing capability ( STOL). It is designed to perform missions like a conventional

with the long-range, high-speed cruise performance of a

aircraft. The FAA classifies the Osprey as a model of

powered lift A powered lift aircraft takes off and lands vertically under engine power but uses a fixed wing for horizontal flight. Like helicopters, these aircraft do not need a long runway to take off and land, but they have a speed and performance similar ...

aircraft. Attempts were made in the 1960s to develop a commercial passenger aircraft with VTOL capability. The Hawker Siddeley Inter-City Vertical-Lift proposal had two rows of lifting fans on either side. However, none of these aircraft made it to production after they were dismissed as too heavy and expensive to operate. In 2018 Opener Aero demonstrated an electrically powered fixed-wing VTOL aircraft, the Blackfly, which the manufacturer claims is the world's first ultralight fixed-wing, all-electric, vertical take-off and landing aircraft.

Modern drones

In the 21st century, unmanned drones are becoming increasingly commonplace. Many of these have VTOL capability, especially the

quadcopter A quadcopter or quadrotor is a type of helicopter with four rotors. Although quadrotor helicopters and convertiplanes have long been flown experimentally, the configuration remained a curiosity until the arrival of the modern UAV or drone. T ...

type.

Jet lift

Tail-sitters

In 1947,

, a

tailsitter 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-sitt ...

design, was ordered by the US Navy, who then further issued a proposal in 1948 for an aircraft capable of vertical takeoff and landing (VTOL) aboard platforms mounted on the afterdecks of conventional ships. Both

and Lockheed competed for the contract but in 1950, the requirement was revised, with a call for a research aircraft capable of eventually evolving into a VTOL ship-based convoy escort fighter.

Conventional design

Rolls-Royce Thrust Measuring Rig science museum

Another more influential early functional contribution to VTOL was

Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...

's Thrust Measuring Rig ("flying bedstead") of 1953. This led to the first VTOL engines as used in the first British VTOL aircraft, the

Short SC.1 The Short SC.1 was the first British fixed-wing vertical take-off and landing (VTOL) jet aircraft. It was developed by Short Brothers. It was powered by an arrangement of five Rolls-Royce RB.108 turbojets, four of which were used for vertical ...

(1957), Short Brothers and Harland, Belfast which used four vertical lift engines with a horizontal one for forward thrust.

The

was the first British fixed-wing VTOL aircraft. The SC.1 was designed to study the problems with VTOL flight and the transition to and from forward flight. The SC.1 was designed to meet a Ministry of Supply (MoS) request for tender (ER.143T) for a vertical take-off research aircraft issued in September 1953. The design was accepted by the ministry and a contract was placed for two aircraft (XG900 and XG905) to meet Specification ER.143D dated 15 October 1954. The SC.1 was also equipped with the first "fly-by-wire" control system for a VTOL aircraft. This permitted three modes of control of the aerodynamic surfaces or the nozzle controls. The

Republic Aviation The Republic Aviation Corporation was an American aircraft manufacturer based in Farmingdale, New York, on Long Island. Originally known as the Seversky Aircraft Company, the company was responsible for the design and production of many important ...

AP-100 was a prototype VTOL 6x

General Electric J85 The General Electric J85 is a small single-shaft turbojet engine. Military versions produce up to of thrust dry; afterburning variants can reach up to . The engine, depending upon additional equipment and specific model, weighs from . It is on ...

Turbojet engined nuclear capable strike fighter concept designed by

Alexander Kartveli Alexander Kartveli, born Aleksandre Kartvelishvili, ( ka, ალექსანდრე ქართველიშვილი) (September 9, 1896 – July 20, 1974) was a Georgian aeronautical engineer and an aviation pioneer in the United ...

that had 3x ducted fans in the centre of its fuselage and tail as a possible contender for the

TFX Program The United States Air Force and Navy were both seeking new aircraft when Robert McNamara was appointed U.S. Secretary of Defense in January 1961. The aircraft sought by the two armed services shared the need to carry heavy armament and fuel loads, ...

. Another design was the A400 AVS that used variable geometry wings but was found too complicated, however it led to the development of the AFVG which in turn helped the development of the

Panavia Tornado The Panavia Tornado is a family of twin-engine, variable-sweep wing multirole combat aircraft, jointly developed and manufactured by Italy, the United Kingdom and West Germany. There are three primary Tornado variants: the Tornado IDS ( in ...

The

Yakovlev Yak-38 The Yakovlev Yak-38 (russian: Яковлев Як-38; NATO reporting name: "Forger") was the Soviet Naval Aviation's only operational VTOL strike fighter aircraft in addition to being its first operational carrier-based fixed-wing aircraft. It ...

was a Soviet Navy VTOL aircraft intended for use aboard their light carriers, cargoships, and capital ships. It was developed from the

Yakovlev Yak-36 The Yakovlev Yak-36, also known as ''Izdeliye V'', (NATO reporting name "Freehand") is a Soviet technology demonstrator for a VTOL combat aircraft. Design and development From 1960, the Yakovlev Design Bureau began work on a VTOL system, using ...

experimental aircraft in the 1970s. Before the Soviet Union broke up, a supersonic VTOL aircraft was developed as the Yak-38's successor, the

Yak-141 The Yakovlev Yak-141 (russian: Яковлев Як-141; NATO reporting name "Freestyle"), also known as the Yak-41, is a Soviet supersonic vertical takeoff/landing (VTOL) fighter aircraft designed by Yakovlev. It was used for testing. Desi ...

, which never went into production. Aircraft VJ101C top

In the 1960s and early 1970s, Germany planned three different VTOL aircraft. One used the

Lockheed F-104 Starfighter The Lockheed F-104 Starfighter is an American single-engine, supersonic air superiority fighter which was extensively deployed as a fighter-bomber during the Cold War. Created as a day fighter by Lockheed as one of the "Century Series" of fi ...

as a basis for research for a

aircraft. Although two models (X1 and X2) were built, the project was canceled due to high costs and political problems as well as changed needs in the German Air Force and NATO. The

EWR VJ 101 The EWR VJ 101 was an experimental German jet fighter vertical takeoff/landing (VTOL) tiltjet aircraft. VJ stood for ''Versuchsjäger'', (German for "Experimental Fighter"). The VJ 101 was one of the first V/STOL designs to have the potential f ...

C did perform free VTOL take-offs and landings, as well as test flights beyond mach 1 in the mid- and late 60s. One of the test-aircraft is preserved in the

Deutsches Museum The Deutsches Museum (''German Museum'', officially (English: ''German Museum of Masterpieces of Science and Technology'')) in Munich, Germany, is the world's largest museum of science and technology, with about 28,000 exhibited objects from ...

in Munich, Germany, another outside Friedrichshafen Airport. The others were the VFW-Fokker VAK 191B light fighter and reconnaissance aircraft, and the

Dornier Do 31 The Dornier Do 31 is an experimental vertical take-off and landing (VTOL) jet-propelled transport designed and produced by West German aircraft manufacturer Dornier. The development of the Do 31 was motivated principally by heavy interest exp ...

E-3 (troop) transport. The LLRV was a

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

simulator for the Apollo lunar lander. It was designed to mimic the flight characteristics of the lunar module (LEM), which had to rely on a reaction engine to land on the Moon. The idea of using the same engine for vertical and horizontal flight by altering the path of the thrust was conceived by

Michel Wibault Michel Henri Marie Joseph Wibault (born 5 June 1897, died 23 January 1963) was a French aircraft designer. He was a strong advocate of metal construction, and his airliners were important in the development of French commercial aviation in the 1 ...

. It led to the Bristol Siddeley Pegasus engine which used four rotating nozzles to direct thrust over a range of angles. This was developed side by side with an airframe, the Hawker P.1127, which became subsequently the Kestrel and then entered production as the

Hawker Siddeley Harrier The Hawker Siddeley Harrier is a British military aircraft. It was the first of the Harrier series of aircraft and was developed in the 1960s as the first operational ground attack and reconnaissance aircraft with vertical/short takeoff an ...

, though the supersonic

Hawker Siddeley P.1154 The Hawker Siddeley P.1154 was a planned supersonic vertical/short take-off and landing (V/STOL) fighter aircraft designed by Hawker Siddeley Aviation (HSA). Development originally started under P.1150, which was essentially a larger and fas ...

was canceled in 1965. The French in competition with the P.1154 had developed a version of the

Dassault Mirage III The Dassault Mirage III () is a family of single/dual-seat, single-engine, fighter aircraft developed and manufactured by French aircraft company Dassault Aviation. It was the first Western European combat aircraft to exceed Mach number, Mach 2 ...

capable of attaining Mach 1. The

Dassault Mirage IIIV The Dassault Mirage IIIV, also spelled Mirage III V, was a French vertical take-off and landing (VTOL) prototype fighter aircraft of the mid-1960s developed and produced by Dassault Aviation. The Mirage IIIV was a VTOL derivative of an existi ...

achieved transition from vertical to horizontal flight in March 1966, reaching Mach 1.3 in level flight a short time later.

V/STOL

INAS 300 Sea Harrier vertical landing on a carrier

The Harrier is usually flown in

mode, which enables it to carry a higher fuel or weapon load over a given distance. In V/STOL the VTOL aircraft moves horizontally along the runway before taking off using vertical thrust. This gives aerodynamic lift as well as thrust lift and permits taking off with heavier loads and is more efficient. When landing the aircraft is much lighter due to the loss of propellant weight and a controlled vertical landing is possible. An important aspect of Harrier STOL operations aboard naval carriers is the "ski jump" raised forward deck, which gives the craft additional vertical momentum at takeoff. The March 1981 cover of Popular Science showed three illustrations for its "Tilt-engine V/STOL - speeds like a plane, lands like a copter" front-page feature story.; a followup story was part of the April 2006 issue that mentioned "the fuel-consumption and stability problems that plagued earlier plane/copter." Retired from the British

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...

in 2006, the

Indian Navy The Indian Navy is the maritime branch of the Indian Armed Forces. The President of India is the Supreme Commander of the Indian Navy. The Chief of Naval Staff, a four-star admiral, commands the navy. As a blue-water navy, it operates si ...

continued to operate

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 servic ...

s until 2016, mainly from its aircraft carrier . The latest version of the Harrier, the

BAE 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 develop ...

, was retired in December 2010 after being operated by the British

Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...

and Royal Navy. The

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...

and the Italian and Spanish navies all continue to use the

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 ...

, an American-designed equivalent version. Replacing the Harrier II/AV-8B in the air arms of the US and UK is the STOVL variant of the

Lockheed Martin F-35 Lightning II The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather Stealth aircraft, stealth multirole combat aircraft that is intended to perform both Air superiority fighter, air superiority and attack ...

, the F-35B.

Rockets

SpaceX developed several prototypes of Falcon 9 to validate various low-altitude, low-velocity engineering aspects of its reusable launch system development program. The first prototype, Grasshopper, made eight successful test flights in 2012–2013. It made its eighth, and final, test flight on October 7, 2013, flying to an altitude of before making its eighth successful VTVL landing. This was the last scheduled test for the Grasshopper rig; next up will be low altitude tests of the Falcon 9 Reusable (F9R) development vehicle in Texas followed by high altitude testing in New Mexico.'' On November 23, 2015, Blue Origin's New Shepard booster rocket made the first successful vertical landing following an uncrewed suborbital test flight that reached space. On December 21, 2015, SpaceX

Falcon 9 Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX. The rocket has two stages. The first (booster) stage carries the second stage and pay ...

first stage made a successful landing after boosting 11 commercial satellites to

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

on Falcon 9 Flight 20. These demonstrations opened the way for substantial reductions in space flight costs.

Rotorcraft

Helicopter

The helicopter's form of VTOL allows it to take off and land vertically, to hover, and to fly forwards, backwards, and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft would usually not be able to take off or land. The capability to efficiently hover for extended periods of time is due to the helicopter's relatively long, and hence efficient rotor blades, and allows a helicopter to accomplish tasks that fixed-wing aircraft and other forms of vertical takeoff and landing aircraft could not perform at least as well until 2011. On the other hand, the long rotor blades restrict the maximum speed to about 250 miles per hour (400 km/h) of at least conventional helicopters, as

retreating blade stall Retreating blade stall is a hazardous flight condition in helicopters and other rotary wing aircraft, where the retreating rotor blade has a lower relative blade speed, combined with an increased angle of attack, causing a stall and loss of lift ...

causes lateral instability.

Autogyro

Autogyros are also known as gyroplanes or gyrocopters. The rotor is unpowered and rotates freely in the airflow as the craft travels forward, so the craft needs a conventional powerplant to provide thrust. An autogyro is not intrinsically capable of VTOL: for VTO the rotor must be spun up to speed by an auxiliary drive, and vertical landing requires precise control of rotor momentum and pitch.

Gyrodyne

Gyrodynes are also known as compound helicopters or compound gyroplanes. A gyrodyne has the powered rotor of a helicopter with a separate forward thrust system of an autogyro. Apart from take-off and landing the rotor may be unpowered and autorotate. Designs may also include stub wings for added lift.

Cyclogyro

A cyclogyro or cyclocopter has a rotary wing whose axis and surfaces remain sideways across the airflow, as with a conventional wing.

Powered lift

Convertiplane

A convertiplane takes off under rotor lift like a helicopter, then transitions to fixed-wing lift in forward flight.

Tiltrotor

A tiltrotor or proprotor tilts its propellers or rotors vertically for VTOL and then tilts them forwards for horizontal wing-borne flight, while the main wing remains fixed in place.

Tilting ducted fan

Similar to tiltrotor concept, but with ducted fans. As it can be seen in the

Bell X-22 The Bell X-22 is an American V/STOL X-plane with four tilting ducted fans. Takeoff was to selectively occur either with the propellers tilted vertically upwards, or on a short runway with the nacelles tilted forward at approximately 45°. Additio ...

Tiltwing

A tiltwing has its propellers or rotors fixed to a conventional wing and tilts the whole assembly to transition between vertical and horizontal flight.

Tail-sitter

A tail-sitter sits vertically on its tail for takeoff and landing, then tilts the whole aircraft forward for horizontal flight.

Vectored thrust

Thrust vectoring is a technique used for jet and rocket engines, where the direction of the engine exhaust is varied. In VTOL, the exhaust can be varied between vertical and horizontal thrust.

Tiltjet

Similar to tiltrotor concept, but with turbojet or turbofan engines instead of ones with propellers.

Lift jets

A lift jet is an auxiliary jet engine used to provide lift for VTOL operation, but may be shut down for normal wing-borne flight.

Lift fans

Lift fan is an aircraft configuration in which lifting fans are located in large holes in an otherwise conventional fixed wing or fuselage. It is used for V/STOL operation. The aircraft takes off using the fans to provide lift, then transitions to fixed-wing lift in forward flight. Several experimental craft have been flown, but only the

F-35 Lightning II The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather stealth multirole combat aircraft that is intended to perform both air superiority and strike missions. It is also able to provide elect ...

entered into production.

Lift via Coandă effect

Aircraft in which VTOL is achieved by exploiting the Coandă effect are capable of redirecting air much like

thrust vectoring Thrust vectoring, also known as thrust vector control (TVC), is the ability of an aircraft, rocket, or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) to control the attitude or angular velocity of the ve ...

, but rather than routing airflow through a duct, the airflow is simply routed along an existing surface, which is usually the body of the craft allowing less material and weight. The

Avro Canada VZ-9 Avrocar The Avro Canada VZ-9 Avrocar was a VTOL aircraft developed by Avro Canada as part of a secret U.S. military project carried out in the early years of the Cold War. The Avrocar intended to exploit the Coandă effect to provide lift and thrust ...

, or simply the VZ-9, was a Canadian VTOL aircraft developed by Avro Aircraft Ltd. which utilizes this phenomenon by blowing air into a central area, then it is directed down over the top surface, which is parabolic and resembles a bowed

flying saucer A flying saucer (also referred to as "a flying disc") is a descriptive term for a type of flying craft having a disc or saucer-shaped body, commonly used generically to refer to an anomalous flying object. The term was coined in 1947 but has g ...

. Due to the Coandă effect, the airflow is attracted to the nearest surface and continues to move along that surface despite the change in the surface's direction away from the airflow. The craft is designed to direct the airflow downward to provide lift. Jetoptera announced a proposed line of aircraft based on what it called fluidic propulsion that employs the Coandă effect. The company claims an

Oswald efficiency number The Oswald efficiency, similar to the span efficiency, is a correction factor that represents the change in drag with lift of a three-dimensional wing or airplane, as compared with an ideal wing having the same aspect ratio and an elliptical lift ...

of 1.45 for its boxwing design. Other claims include increased efficiency, quieter operation and scalability.

Gallery

File:F-35 compilation.ogg, F-35 flight, transition to STOVL configuration, vertical take off, inflight re-fueling, vertical hover and landing File:F-35 vertical landing.ogg, F-35 vertical landing

References

Notes

Bibliography

* Allen, Francis J. "Bolt upright: Convair's and Lockheed's VTOL fighters". ''Air Enthusiast'' (Key Publishing), Volume 127, January/February 2007. . * Boniface, Patrick. "Tilt-wing Testing". ''Aeroplane,'' Vol. 28, no. 3, March 2000, pp. 72–78. * Campbell, John P. ''Vertical Takeoff & Landing Aircraft.'' New York: The MacMillan Company, 1962. * Harding, Stephen. "Flying Jeeps: The US Army's Search for the Ultimate 'Vehicle'". ''Air Enthusiast'', No. 73, January/February 1998, pp. 10–12. Stamford, Lincs, UK: Key Publishing. . * Jackson, Paul A. ''German Military Aviation 1956–1976''. Hinckley, Leicestershire, UK: Midland Counties Publications, 1976. . * Khurana, K. C. ''Aviation Management: Global Perspectives''. Singapore: Global India Publications, 2009. . * Markman, Steve and Bill Holder. ''Straight Up: A History of Vertical Flight''. Atglen, Pennsylvania: Schiffer Publishing, 2000. . * Norton, Bill. ''Bell Boeing V-22 Osprey, Tiltrotor Tactical Transport''. Earl Shilton, Leicester, UK: Midland Publishing, 2004. . * Rogers, Mike. ''VTOL: Military Research Aircraft''. New York: Orion Books, 1989. . * Büchi, Roland. ''Fascination Quadrocopter''. Norderstedt, BoD, English Version, 2011.

External links

V/STOL Wheel of Misfortune
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Timeline of V/STOL aircraft
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