V/STOL

British Aerospace Harrier II at RIAT 2008

Vertical and/or short take-off and landing (V/STOL) is a term used to describe aircraft that are able to take-off or land vertically or on short runways. Vertical takeoff and landing (VTOL) describes craft which do not require runways at all. Generally, a V/STOL aircraft needs to be able to hover; helicopters are not typically considered under the V/STOL classification.

Most V/STOL aircraft types were experiments or outright failures from the 1950s to 1970s. V/STOL aircraft types that have been produced in large numbers include the Harrier, Yak-38 Forger and V-22 Osprey.

RAF Harrier GR9 arrives at RIAT 2008

A rolling takeoff, sometimes with a ramp (ski-jump), reduces the amount of thrust required to lift an aircraft from the ground (compared with vertical takeoff), and hence increases the payload and range that can be achieved for a given thrust. For instance, the Harrier is incapable of taking off vertically with a full weapons and fuel load. Hence V/STOL aircraft generally use a runway if it is available. I.e. Short Take Off and Vertical Landing (STOVL) or Conventional Take-off and Landing (CTOL) operation is preferred to VTOL operation.

V/STOL was developed to allow fast jets to be operated from clearings in forests, from very short runways, and from small aircraft carriers that would previously only have been able to carry helicopters.

The main advantage of V/STOL aircraft is closer basing to the enemy, which reduces response time and tanker support requirements. In the case of the Falklands War, it also permitted high performance fighter air cover and ground attack without a large aircraft carrier equipped with a catapult.

The latest V/STOL aircraft is the F-35B, which is expected to enter service in 2016.

Lists of V/STOL aircraft

This is a partial list, there have been many designs for V/STOL aircraft.

Vectored thrust

• Ryan XV-5. Ducts in wings with half-trash can lid covers.
• Hawker P.1127/Kestrel/Harrier; four rotating nozzles for vectored thrust of fan and jet exhaust.

Tilt-rotor

• Bell XV-3
• Bell XV-15
• Bell 609
• Bell-Boeing V-22 Osprey (scale up of XV-15)

Tilt-wing

• Fairchild X-19 - four rotating propellers, tilt-wing.
• Canadair CL-84 Dynavert, two turboprop tilt-wing in RCAF service from 1960
• LTV XC-142 four-engine tilt-wing cross-shafted turboprop
• Bell X-22 rotating ducted propellers. Small transport prototype. Slightly smaller than V-22 Osprey.
• Hiller X-18

Separate thrust and lift

• Kamov Ka-22
• Lockheed XV-4 Hummingbird
• Mirage "Balzac" V (V stands for vertical and is a modified Mirage III)
• Mirage III V the first VTOL capable of supersonic flight (Mach 2.03 during tests)
• Yakovlev Yak-141 Flown, but not operational
• Yakovlev Yak-38

Supersonic

Although many aircraft have been proposed, built, and some even tested, the F-35B is expected to be the first supersonic VTOL aircraft in operational service.

• Bell D-188A Mach 2 swivelling engines, mockup stage
• EWR VJ 101 Mach 2 fighter from Germany similar to Bell D-188A, flown to M1.04 but not operational
• Mirage III V the first VTOL capable of supersonic flight (Mach 2.03 during tests), not operational
• Hawker Siddeley P.1154 M1.7 Supersonic Harrier. Never built
• Rockwell XFV-12 Built but could not lift its own weight
• Yakovlev Yak-141 Flown, but not operational
• Lockheed Martin X-35B/F-35B uses a vectored-thrust engine (the Pratt & Whitney F135) plus a lifting fan. First aircraft capable of demonstrating transition from short take-off to supersonic flight to vertical landing on the same sortie.

External links

• V/STOL Wheel of Misfortune