From Wikipedia, the free encyclopedia

It has been suggested that this article or section be merged into VTOL. (Discuss)

Vertical/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. Most were experiments or outright failures from the 1950s to 1970s. Vertical takeoff and landing (VTOL) is a subset of V/STOL for craft which do not require short runways.

The Hawker Siddeley Harrier is perhaps the most famous production V/STOL aircraft. The Harrier is the only truly operational successful design to date. The Yak-38 Forger was another operational aircraft but is now out of commission and was very problematic. Helicopters have continued to dominate vertical flight and Gyrocopters the STOL one in the ultra light weight class.

V/STOL was originally developed to allow fast jets to be operated from clearings in forests, removing their reliance on damage-prone runways, or operated from small aircraft carriers that would previously only have been able to carry helicopters.

V/STOL has been replaced by STOVL or short takeoff, vertical landing in operation, if not in design. A rolling takeoff, sometimes with a ramp reduces the amount of thrust required to lift a fully laden aircraft from the ground, and increases the payload and range. For instance, the Harrier is incapable of taking off vertically with a full weapons and fuel load, and hence is operated as STOVL wherever possible.

The main advantages in the case of the Harrier is closer basing, 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 catapult-based aircraft carrier.

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

Tail-sitters

• Lockheed XFV - prop tail sitter.
• Convair XFY - prop tail sitter.
• Ryan X-13 Vertijet jet tail sitter. Demonstrated in DC, lands on rig that can be transported over roads.

Vectored thrust

• Ryan XV-5. Ducts in wings with half-trash can lid covers.
• Hawker P.1127/Kestrel. Prototype and evaluation versions that became the Harrier; 4 rotating nozzles for vectored thrust of fan and turbojet exhaust.

Tilt-rotor

• Bell XV-3
• Bell XV-15
• Bell-Boeing V-22 Osprey Transport replacement for CH-46, delayed by development and safety problems. Tilt rotor scale up of XV-15.

Tilt-wing

• Fairchild X-19 - 4 rotating propellers, tilt-wing.
• Canadair CL-84 Dynavert, 2 turbo prop tilt-wing in RCAF service from 1960
• LTV Vought XC-142 4 engine tilt-wing cross-shafted turbo prop
• Bell X-22 rotating ducted propellers. Small transport prototype. Flew fine, slightly smaller than V-22 Osprey.

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)
• Lockheed Martin X-35B/F-35B Prototype and production version use a vectored-thrust main engine (the Pratt & Whitney F135), plus a lifting engine (the Rolls-Royce LiftFan). First aircraft capable of demonstrating transition from vertical to supersonic flight on the same sortie.
• Yakovlev Yak-38

• V/STOL wheels of misfortune