VTOL

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Types of
take-off and
landing

CTOL

STOL

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 normally 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 — the Bell Boeing V-22 Osprey
Using directed jet thrust — the Hawker-Siddeley Harrier "Jump jet" and its successor designs, the BAe/Boeing Harrier II.

[edit] History

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. 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.

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 that utilizes a similar concept.

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.

In the 1960's and early 70's Germany used the F-104 as a base 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 Luftwaffe 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 60's. One of the test-aircraft is preserved in the Deutsches Museum in Munich, Germany.

The Moller Skycar is a prototype personal VTOL aircraft -- literally, a "flying air vehicle" (PAV). It has, as of this date, never made the transition to level flight, nor has it ever flown with anybody on board.

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.

[edit] Media

F-35 flight (video) (file info)
- F-35 flight, good image of transition to VTOL configuration, vertical take off, inflight re-fueling, vertical hover and landing.
F-35 verticle landing (video) (file info)
- Vertical landing (video)
Problems seeing the videos? See media help.