A vertical take-off and landing (VTOL) aircraft is one that can hover,
take off, and land vertically. This classification can include a
variety of types of aircraft including fixed-wing aircraft as well as
helicopters and other aircraft with powered rotors, such as
cyclogyros/cyclocopters and tiltrotors. Some
VTOL aircraft can
operate in other modes as well, such as
CTOL (conventional take-off
STOL (short take-off and landing), and/or
take-off and vertical landing). Others, such as some helicopters, can
only operate by VTOL, due to the aircraft lacking landing gear that
can handle horizontal motion.
VTOL is a subset of V/
and/or short take-off and landing).
Besides the ubiquitous helicopter, there are currently two types of
VTOL aircraft in military service: craft using a tiltrotor, such as
the Bell Boeing V-22 Osprey, and another using directed jet thrust,
such as the Harrier family and new F-35B Lightning II Joint strike
Fighter (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 as of 2017[update]). Generally
VTOL aircraft capable of
STOVL use it wherever possible,
since it typically significantly increases takeoff weight, range or
payload compared to pure VTOL.
1.1 Props, proprotors and advanced rotorcraft
1.2 Jet lift
1.4 Modern drones
3 Powered lift
3.3 Vectored thrust
3.4 Lift jets
3.5 Lift fans
3.6 Lift via Coandă effect
5 See also
7 External links
Props, proprotors and advanced rotorcraft
Helicopter § History, and
Tiltrotor § History
The idea of vertical flight has been around for thousands of years and
sketches for a
VTOL (helicopter) shows up in Leonardo da Vinci'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 helicopter development, many approaches have been tried
to develop practical aircraft with vertical take-off and landing
capabilities including Henry Berliner's 1922–1925 experimental
horizontal rotor fixed wing aircraft, and Nikola Tesla's 1928 patent
and George Lehberger's 1930 patent for relatively impractical VTOL
fixed wing airplanes with a tilting engines. In the late
1930s British aircraft designer Leslie Everett Baynes was issued a
patent for the Baynes Heliplane, another tilt rotor aircraft. In 1941
German designer Heinrich Focke's began work on the Focke-Achgelis Fa
269, which had two rotors that tilted downward for vertical takeoff,
but wartime bombing halted development.
Convair XFY-1 Pogo in flight
In May 1951, both Lockheed and
Convair were awarded contracts in the
attempt to design, construct, and test two experimental
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 X-13 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.
NASA has flown other
VTOL craft such as the
Bell XV-15 research craft
(1977), as have the
Soviet Navy and Luftwaffe. Sikorsky tested an
aircraft dubbed the X-Wing, 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 is a
Canard Rotor/Wing prototype that utilizes a similar
Fairey Jet Gyrodyne
A different British
VTOL project was the gyrodyne, 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, that used tipjets
to power the rotor on take-off and landing but which then used two
Napier Eland turboprops 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.
U.S. Marines jump from a V-22 Osprey, the first production tiltrotor
CL-84-1 (CX8402) on display at the
Canada Aviation and Space Museum
Canada Aviation and Space Museum in
The CL-84 was a Canadian V/
STOL 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
Although tiltrotors such as the
Focke-Achgelis Fa 269
Focke-Achgelis Fa 269 of the mid-1940s
and the Centro Técnico Aeroespacial "Convertiplano" of the 1950s
reached testing or mock-up stages, the
V-22 Osprey is considered the
world's first production tiltrotor aircraft. It has one three-bladed
proprotor, turboprop engine, and transmission nacelle 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
helicopter with the long-range, high-speed cruise performance of a
turboprop aircraft. The FAA classifies the Osprey as a model of
powered lift aircraft.
Attempts were made in the 1960s to develop a commercial passenger
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.
The Ryan X-13
In 1947, Ryan X-13 Vertijet, a tailsitter 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
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.
"Flying Bedstead"- Rolls-Royce Thrust Measuring Rig
Another more influential early functional contribution to
Rolls-Royce's Thrust Measuring Rig ("flying bedstead") of 1953. This
led to the first
VTOL engines as used in the first British VTOL
Short SC.1 (1957), Short Brothers and Harland, Belfast
which used four vertical lift engines with a horizontal one for
Short SC.1 a
VTOL delta aircraft
Short SC.1 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
VTOL aircraft. This permitted three modes of control of the
aerodynamic surfaces and/or the nozzle controls.
The Soviet Union's
VTOL aircraft, the
Yakovlev Yak-38 was a
VTOL aircraft intended for use
aboard their light carriers, cargoships, and capital ships. It was
developed from the
Yakovlev Yak-36 experimental aircraft in the 1970s.
Soviet Union broke up, a supersonic
VTOL aircraft was
developed as the Yak-38's successor, the Yak-141, which never went
A German V/
STOL VJ101 on display at the Deutsches Museum, Munich,
Do 31 E3 on display at the Deutsches Museum, Germany
In the 1960s and early 1970s, Germany planned three different VTOL
aircraft. One used the
Lockheed F-104 Starfighter
Lockheed F-104 Starfighter as a basis for
research for a V/
STOL 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
German Air Force and NATO.
The EWR VJ 101C 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 in Munich, Germany.
The others were the VFW-Fokker VAK 191B light fighter and
reconnaissance aircraft, and the Dornier Do 31E-3 (troop)
LLRV was a spacecraft 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
The idea of using the same engine for vertical and horizontal flight
by altering the path of the thrust 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, though the supersonic
Hawker Siddeley P.1154 was canceled in 1965. The French in competition
with the P.1154 had developed a version of the Dassault Mirage III
capable of attaining Mach 1. The
Dassault Mirage IIIV
Dassault Mirage IIIV achieved
transition from vertical to horizontal flight in March 1966, reaching
Mach 1.3 in level flight a short time later.
The Harrier is usually flown in
STOVL mode, which enables it to carry
a higher fuel or weapon load over a given distance. In V/
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.
Now retired from British
Royal Navy service, the
Indian Navy operates
Sea Harriers mainly from its aircraft carrier INS Viraat. The latest
version of the Harrier, the
BAE Harrier II
BAE Harrier II has also been retired in
December 2010, after being operated by the British
Royal Air Force
Royal Air Force and
Royal Navy. The United States Marine Corps, and the Italian and
Spanish Navies use the AV-8B Harrier II, an equivalent derivative of
the Harrier II. The Harrier II/AV-8 will be replaced in the air arms
of the US and UK by a
STOVL variant of the Lockheed Martin F-35
Lightning II. An important aspect of Harrier
STOL operations aboard
Naval carriers was the "ski jump" raised forward deck, which gave the
craft additional vertical momentum at takeoff.
A Schiebel Camcopter S-100, a modern
VTOL unmanned aerial vehicle
In the 21st century, unmanned drones are becoming increasingly
commonplace. Many of these have
VTOL capability, especially the
quadcopter type. Others, such as the
Schiebel Camcopter S-100
Schiebel Camcopter S-100 are more
Grasshopper was a
VTVL first-stage booster test vehicle SpaceX
developed to validate various low-altitude, low-velocity engineering
aspects of its large-vehicle reusable rocket technology. The test
vehicle made eight successful test flights in 2012–2013.
Grasshopper v1.0 made its eighth, and final, test flight on October 7,
2013, flying to an altitude of 744 metres (2,441 ft) (0.46 miles)
before making its eighth successful
On November 23, 2015, Blue Origin's New Shepard booster rocket made
the first successful vertical landing following an unmanned suborbital
test flight that reached space. On December 21, 2015, SpaceX's
Falcon 9 first stage made a successful landing after boosting 11
commercial satellites to low earth orbit on
Falcon 9 Flight 20.
These demonstrations potentially open the way for substantial
reductions in space flight costs.
Main article: 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 causes lateral instability.
Main article: 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.
Main article: 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.
Main article: Cyclogyro
A cyclogyro or cyclocopter has a rotary wing whose axis and surfaces
remain sideways across the airflow, as with a conventional wing.
Main article: Powered lift
Main article: Convertiplane
A convertiplane takes off under rotor lift like a helicopter, then
transitions to fixed-wing lift in forward flight.
Main article: 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.
Main article: Tiltjet
Similar to tiltrotor concept, but with turbojet or turbofan engines
instead of ones with propellers.
Main article: Tiltwing
A tiltwing has its propellers or rotors fixed to a conventional wing
and tilts the whole assembly to transition between vertical and
Main article: Tail-sitter
A tail-sitter sits vertically on its tail for takeoff and landing,
then tilts the whole aircraft forward for horizontal flight.
Main article: Thrust vectoring
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.
Main article: Lift jet
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.
Main article: Lift fan
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/
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
F-35 Lightning II entered into
Lift via Coandă effect
Main article: Coandă effect
Aircraft in which
VTOL is achieved by exploiting the Coandă effect
are capable of redirecting air much like thrust vectoring, 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, 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. 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.
F-35 flight, transition to
STOVL configuration, vertical take off,
inflight re-fueling, vertical hover and landing
F-35 vertical landing
Nikola Tesla patents
McDonnell Douglas DC-X
Reusable Vehicle Testing project of the Japanese Space Agency JAXA
^ Laskowitz, I.B. "Vertical Take-Off and
Landing (VTOL) Aircraft."
Annals of the New York Academy of Sciences, Vol. 107, Art.1, 25 March
^ a b Khurana KC (2009). Aviation Management: Global Perspectives.
^ Yefim Gordon, The History of VTOL, page 28
^ John Whiteclay Chambers, The Oxford Companion to American Military
History, Oxford University Press, USA, 1999, page 748
^ "U.S. Patent 1,655,113." US Patent Office. Retrieved; 10 July 2011.
^ By A.J.S. RAYL, Nikola Tesla's Curious Contrivance, Air & Space
Magazine, September 2006 – online
^ a b globalsecurity.org, Military Aircraft, Rotary, Tiltrotor
^ Allen 2007, pp. 13–20.
^ "The new Vertijet's straight-up flight: X-13 takes off like a
rocket, lands tailfirst." Life, 20 May 1957, pp. 136–140, 142.
^ Simonsen, Erik. "Another one for the X files: The Boeing Canard
Rotor/Wing demonstrator officially becomes X-50A." Boeing.com.
Retrieved: May 24, 2015.
^ Boniface 2000, p. 74.
^ Norton 2004, pp. 6–9, 95–96.
^ "BAE animates mothballed Intercity Vertical-Lift Aircraft."
Aerospace-technology.com. Retrieved: 24 May 2015.[unreliable source?]
^ "Forgotten 1960s ‘Thunderbirds’ projects brought to life." BAE
Systems. Retrieved: 24 May 2015.
^ "Vertical take-off/landing aircraft: Yak-38."
Bureau, 16 July 2008. Retrieved: 10 July 2011.
^ Jackson 1976, p. 143.
Landing Research Vehicle." Dryden Flight Research Center.
Retrieved: 10 July 2011.
^ "Airfoil". Basics of Aeronautics. Retrieved: 24 May 2015.
^ "Reusable rocket prototype almost ready for first liftoff".
Spaceflight Now. 2012-07-09. Retrieved 2012-07-13.
constructed a half-acre concrete launch facility in McGregor, and the
Grasshopper rocket is already standing on the pad, outfitted with four
insect-like silver landing legs.
^ "Grasshopper Completes Highest Leap to Date". SpaceX.com. 10 March
2013. Retrieved 11 March 2013.
^ The Grasshopper prototype test vehicle has been retired.
"Grasshopper flies to its highest height to date". Social media
information release. SpaceX. 12 October 2013. Retrieved 14 October
2013. WATCH: Grasshopper flies to its highest height to date – 744 m
(2441 ft) into the Texas sky. http://youtu.be/9ZDkItO-0a4 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.
Blue Origin make historic rocket landing." Blue Origin, November
24, 2015. Retrieved: November 24, 2015.
^ "Reusable rockets cheaper." ZME Science, August 20, 2015. Retrieved:
November 24, 2015.
Allen, Francis J. "Bolt upright: Convair's and Lockheed's VTOL
fighters". Air Enthusiast (Key Publishing), Volume 127,
January/February 2007. ISSN 0143-5450.
Boniface, Patrick. "Tilt-wing Testing". Aeroplane, Vol. 28, no. 3,
March 2000, pp. 72–78.
Campbell, John P. Vertical
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. ISBN 978-9-3802-2839-6.
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. ISBN 0-517-57684-8.
Büchi, Roland. Fascination Quadrocopter. Norderstedt, BoD, English
Version, 2011. ISBN 978-3-8423-6731-9
VTOL in Wiktionary, the free dictionary.
Wikimedia Commons has media related to
Doak VZ-4 image
STOL Wheel of Misfortune – Timeline of V/
STOL aircraft, page 5
Types of takeoff and landing
Balanced field takeoff
Takeoff and landing
Launch and recovery cycle
Water landing / Ditching
Floating landing platform