VTOL
VTOL is an abbreviaton for
Vertical Take-Off and Landing.
VTOL describes
fixed-wing aircraft that can lift off vertically. This classification includes only a very
few aircraft;
helicopters,
autogyros;
balloons and
airships are not considered VTOL. Some aircraft can operate in VTOL mode in addition to others, such as
CTOL (Conventional Take-off and Landing) and/or
STOL (Short Take-Off and Landing). Others can only operate by VTOL, due to the aircraft lacking
landing gear that can handle horizontal motion.
Currently there are believed to be two types of practical VTOL aircraft in service:
* Using a
tiltrotor â€" the Bell
Boeing V-22 Osprey * Using directed jet thrust â€" the
Hawker-Siddeley Harrier "Jump jet" and its successor designs, the
BAe/
Boeing Harrier II.
In
1928,
Nikola Tesla received
patents for an apparatus for aerial transportation. Tesla called it the
"Flivver". It is one of the earliest examples of VTOL aircraft.
An early VTOL prototype was
Rolls-Royce's "
flying bedstead", this led to the first British VTOL aircraft, the
Short SC.1 which used a mixture of vertical lift engines and a horizontal one for forward thrust.
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 rotating ducts 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 the Harrier.
The Harrier is often flown in
STOVL mode which enables it to carry a higher fuel or weapon load over a given distance. The Indian and Spanish Navies operate Sea Harriers, mainly from
aircraft carriers.
The United States Marine Corps uses a license-built derivative of the Harrier.
NASA has flown other VTOL craft such as the
XV-15 research craft, 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.
The Harrier will be replaced in the air arms of the US and UK by a
STOVL variant of the
F-35 Joint Strike Fighter.
In the 1960s France developed a version of the
Dassault Mirage III capable of attaining Mach 1. The
Dassault Mirage III - V Balzac (not to be confused with the Mirage 5) achieved transition from vertical to horizontal flight in March of 1966 and reached Mach 1.3 in level flight a short time later.
The
Soviet Yak-38 Forger was the Soviet Navy's VTOL aircraft for their light carriers, cargoships, and capital ships. It was developed from the
Yak-36 Freehand experimental aircraft. Before the Soviet Union collapsed, a supersonic VTOL aircraft was developed as the Yak-38's successor, the
Yak-141, which never went into production. The Yak-141, also called
Yak-41 was further developed into the
Yak-43.
The
Moller Skycar is a prototype personal VTOL aircraft -- literally, a "flying air vehicle" (PAV).
Aircraft designed to operate in extraterrestrial environments often utilize VTOL. An example of this type of aircraft is the
LLRV.
Spacecraft typically operate in environments where runways or even a suitably flat surface for skids is nonexistent.
*
STOL*
List of VTOL aircraft*
Military flying saucers*
Tiltrotor*
Tiltwing*
Tailsitter*
BS100 - a ducted turbofan engine for VTOL use
