Ski-jump (aviation)

In aviation, a ski-jump is an upward-curved ramp that allows aircraft to take off from a runway that is shorter than the aircraft's required takeoff roll. By forcing the aircraft upwards, lift-off can be achieved at a lower airspeed than that required for sustained flight, while allowing the aircraft to accelerate to such speed in the air rather than on the runway. Ski-jumps are commonly used to launch airplanes from aircraft carriers that lack catapults. It is believed that the first use of the ski-jump occurred during the Second World War, where a temporary ramp was added to to assist the take-off of heavily laden Fairey Barracudas conducting a strike mission against the German battleship . During the Cold War era, the concept was studied as a means of reducing the length of flight decks required for future aircraft carriers as well as to facilitate ever-increasingly heavy aircraft at sea. The Royal Navy took a particular interest in the ski-jump during the 1970s, conducting a series of trials in conjunction with the newly developed Hawker Siddeley Harrier VSTOL fighter, before choosing to integrate the feature into their next generation of aircraft carrier, the . Having proven its operational value, numerous naval services have adopted the ski-jump for their own aircraft carriers and amphibious assault platforms, while land-based uses have been examined as well. Ski-jump can be used in two different approaches, these being the Short Take-Off But Arrested Recovery (STOBAR) and the Short Take-Off, Vertical Landing aircraft (STOVL); these pertain to the operation of conventional and VSTOL aircraft respectively. Catapult-equipped aircraft carriers have become a minority in the twenty-first century in part due to the decreased cost and complexity of ski-jump operations. A fixed-wing aircraft must build up forward speed during a lengthy takeoff roll. As the forward velocity increases, the wings produce greater amounts of lift. At a high enough speed, the lift force will exceed the weight of the aircraft, and the aircraft will become capable of sustained flight.