Vertical/Short Takeoff and Landing
From Wikipedia, the free encyclopedia
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. Most were experiments or outright failures from the 1950s to 1970s. Vertical takeoff and landing (VTOL) describes craft which do not require short runways. Generally, a V/STOL aircraft needs to be able to hover; helicopters are not typically considered under the V/STOL classification.
The Hawker Siddeley Harrier is perhaps the most famous production V/STOL aircraft. The Harrier is the only truly operationally successful design in service to date. The Yak-38 Forger was an operational aircraft but had major problems in hot conditions and is out of use. Helicopters have continued to dominate vertical flight.
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.
V/STOL has been replaced by STOVL or short takeoff, vertical landing in operation, if not in design.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 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 catapult-based aircraft carrier.
The latest V/STOL aircraft is the F-35 Lightning II, which will enter service in 2011.
[edit] List 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. Prototype and evaluation versions that became the Harrier; four 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 - four rotating propellers, tilt-wing.
- Canadair CL-84 Dynavert, two turbo prop tilt-wing in RCAF service from 1960
- LTV Vought XC-142 four-engine tilt-wing cross-shafted turbo prop
- Bell X-22 rotating ducted propellers. Small transport prototype. 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
[edit] External links
|
|||||
