At the start of World War II, carriers would often have aircraft take off from their flight decks by rolling and gaining speed. There was, however, a problem with this. As the aircraft got bigger and heavier, the stall speed increased, and at times, a plane could find itself going into the ocean when it reached the end of the flight deck. This was a bad thing, not only because of the loss of an aircraft, but also because a highly-trained naval aviator was usually lost in those circumstances. Naval aviators are much more expensive to train not only must they be able to perform combat missions, but taking off and landing from a carrier is perhaps the toughest task any pilot has taken on.
So, as World War II ended, catapults were introduced. These had been used on battleships and cruisers to launch float planes for scouting. However, as carriers began launching heavier planes, the same technology was used, first on the escort carriers. As the Essex-class carriers began to get bigger, they, too, received catapults.
Catapults have some big advantages: They are powerful, and mean that aircraft like the F-14 (weighing in at over 36 tons fully loaded) can be launched easily. They also give the carrier a lower profile, which is important in a day and age where electronic sensors like radar are used. The technology has also worked well for as long as ships have had float planes (for over ninety years since World War I). They also have disadvantages, Catapults are high-maintenance items, requiring constant attention. If something goes wrong with a catapult, like a cold shot (where the catapult generates insufficient force to launch the aircraft), the aircraft is as good as lost and there is the risk of losing the crew.
The alternative, used by India, Russia, and the United Kingdom, is a ski-jump, often at an angle of seven to fifteen degrees. This has the advantage of being much simpler (no moving parts). The aircraft simply can take off, and pilots do not have to worry about cold shots. It is primarily associated with the VSTOL carriers used by the United Kingdom, Spain, Italy, India, and Thailand. The only fixed-wing carrier that uses this system is the Russian Kuznetov, although Indias Vikramaditya (formerly the Gorshkov) will also use this system.
The ski-jump has disadvantages, though. It cannot launch as many planes as a catapult, since it is often kept on the bow only (the angled deck either is not present or it is kept flat). The ships profile is also higher creating a better target for radar-guided missiles. If the ships bow is hit, it could be unable to launch planes, making a fixed-wing carrier a mission kill (the VSTOL carriers would be able to operate with reduced effectiveness). Still, for navies unable to afford a big maintenance budget, it is a viable option.
Ultimately, which of these option is better depends on what the navy needs. For those that operate VSTOL aircraft like the Harrier and Freestyle or are on a budget, the ski jump makes a lot of sense. It is capable of operating fixed-wing aircraft, and needs no maintenance. For countries launching heavier aircraft, the catapult is a better option, despite its high-maintenance status and the risks involved. Harold C. Hutchison (hchutch@ix.netcom.com)
