Conventional take-off and landing [CTOL] and short take-off and landing [STOL] carriers share a common configuration: a hangar enclosed within a hull, a large flight deck on the hangar roof, take-off runway/s, landing runway/s and pad/s on that flight deck, lifts connecting the hangar and flight decks, and a superstructure off to one side of the flight deck. CTOL carriers such as the USS Nimitz have catapults, arresters and, usually, several runways, some angled. STOL carriers such as HMS Invincible usually have a single through runway serving as take-off runway, landing runway and pad; they usually also have a ski jump because in practice they only operate STOVL and VTOL aircraft. Some 1930s carriers also had an additional take-off runway located on the hangar deck before the hangar, the rear portion of this runway being enclosed under the forward part of the main flight deck.
Another carrier is known, this being a STOVL [short take-off / vertical landing] vessel without a landing runway: a large container ship on which containers stacked before the superstructure form a flight deck with a take-off runway, a pad and a ski jump. A STOVL vessel is an adequate carrier because even STOL vessels in practice only deploy STOVL and VTOL aircraft. VTOL [vertial take-off and landing] carriers are also known: some such as the French Jeanne d'Arc configured with a large hangar aft, a large pad atop it, and lifts connecting those decks; a carrier for V/STOL-as-VTOL aircraft with no pad but using a device developed by British Aerospace to release and recover hovering V/STOL-as-VTOL aircraft has also been proposed. Most VTOL vessels are not aircraft carriers per se, but are other-role ships, usually small, configured in one of two ways: with a hangar on the main deck abaft the superstructure and a pad abaft the hangar; with only an aft pad.
In contrast, CTOL, STOL and STOVL vessels are all large and, effectively, all aircaft carriers; this because all built or proposed have at least one of the following: a fore and aft flight deck with a superstructure beside it and therefore a wide beam; a heavy flight deck on the hangar roof and therefore a hangar of a construction sturdy enough to support it and a large hull to offset the resulting top-heaviness; a hangar enclosed in the hull and therefore a hull of wide beam; a hangar-deck with a take-off runway, that deck therefore being high above the waves; an in-line take-off runway and hangar or in-line take-off runway and superstructure and therefore a long hull; complex and/or heavy machinery like catapults, arresters and, especially, lifts.
Being large and expensive, these ships have to justify their purchase by having one or more of the following that make them even larger and/or more expensive: permanent air groups as large as the ships can carry and which, because the ships are large, are quite large; full and comprehensive servicing and maintenance facilities; large fuel and weapons storage capacity; an all-weather capability and therefore a high-profile but still stable and thus large hull. This overall expense means a number of other-role ships are not built.
Carriers justify their expense and this forgoing of other ships with their air groups' potency; their expense, the forgoing of other ships and this potency in turn means carriers are both unriskable and a prime target to an enemy and therefore they are either or both: armed and/or armoured and therefore even larger and more costly; provided permanently with heavily-armed escorts--making them more attractive as targets as elimination of a carrier leaves its escorts without air cover. Carriers being unriskable, such weapons, whether fitted to carriers or to escorts, are largely restricted to defense as carriers must stay as far as possible from an enemy; their air groups effectively being the sole offensive weapon. All this in effect means carriers are single-role vessels: even if as heavily armed as a cruiser, they will not undertake tasks a more expendable cruiser can undertake.
A balanced carrier navy, unless it is certain it will only go to war accompanied by allies, will have at least two of these expensive ships, their expensive air groups, their escorts, and other ships for independent operations. This allows at least one carrier group to be available for service at all times, while the other undergoes maintenance. A one-carrier navy has a show boat, a two carrier navy has a potentent power projection platform. Such a navy with CTOL carriers can overwhelm any non-carrier navy and most land-based air forces. STOL or STOVL carrier navies are superior to navies not so equipped.
These are the advantages of carriers; the disadvantage is expense, an expense that cannot be reduced because vessels with a runway above a hangar or a runway before a hangar, as noted, must be large. STOL and STOVL carriers have another disadvantage: because they are small, their air groups are too small to ensure protection against land-based CTOL aircraft. Few nations can afford the balanced two-carrier navies described so most rely on fighting ship navies comprising destroyers, frigates, light frigates, corvettes and/or fast attack craft and any requisite support and assault ships. Unlike a carrier navy, such navies have no minimum size or expense. The larger ones comprise destroyers, frigates, assault and support ships, these today generally being (helicopter-deploying) VTOL vessels with a hangar and pad on the main desk as described above.
The combination can be fitted to them because it is compact and unintrusive: the pad is small: the size of the air group determines the hangar's size and air groups being small, so is the hangar; the hangar supports no flight deck on its roof so the hangar is of light construction; the hangar roof, the decks below, most of the main deck and most of the air space around the ship are not intruded upon by aircraft facilities or operations so the equipment for the ships' other roles is easily fitted. Among these ships' advantages are: there is no minimum size for their air groups, indeed air groups can even be not deployed as ships with the hangar and pad are hardly more costly than ones without them; the VTOL capability need not be an all-weather or full-maintenance one so savings in vessel size and equipment are possible; fleets of VTOL destroyers and frigates can be dispersed or concentrated at will, when dispersed each vessel has its own air group, when concentrated the force has no prime target at its core and its VTOL capability is not eliminated till the last ship is sunk; no ship is unriskable and so they can be deployed forward where all their weapons can be used.
The deficiency of such navies is their lack of fixed-wing aircraft. V/STOL-as-VTOL aircraft can be deployed on larger VTOL ships but the aircraft's limited range means they are not sufficiently superior to ship-launched missiles to persuade many navies to purchase them.
"vessel" is a waterborne or amphibious ship, vessel or craft.
"hull and propulsive system" is the hull or equivalent and the means of propulsion of a vessel.
"CTOL aircraft" are fixed-wing aircraft like the McDonnell Douglas F/A-18 which launch and land horizontally in the conventional manner on a long runway or on a medium-length runway if assisted by catapults and arresters.
"STOL aircraft" are fixed-wing aircraft that launch and land unassisted horizontally on a short runway.
"V/STOL aircraft" are fixed-wing aircraft like the British Aerospace Harrier that can launch and land unassisted both horizontally on a short runway and vertically.
"STOVL aircraft" are V/STOL aircraft when their manner of operation is to usually launch horizontally and to land vertically.
"V/STOL-as-VTOL aircraft" are V/STOL aircraft when their only manner of operation is to launch and land vertically.
"VTOL aircraft" are V/STOL-as-VTOL aircraft or aircraft such as helicopters which can only launch and land vertically.
"aircraft" are CTOL, STOL, STOVL or VTOL aircraft.
"take-off runway" is a runway on a vessel aligned approximately in the fore and aft direction and having unobstructed air space forward of its forward end so that CTOL, STOL and/or STOVL aircraft can launch from it.
"catapult" is the device usually called that embedded in a take-off runway and used on vessels to assist CTOL aircraft launching.
"ski jump" is the ramp usually called that located at the forward end of a take-off runway and inclined upward in the forward direction and used on vessels to assist STOVL aircraft launching.
"landing runway" is a runway on a vessel aligned approximately in the fore and aft direction and having unobstructed air space above and abaft it so that CTOL and/or STOL aircraft can land upon it; in this specification, even if a such a runway is also a take-off runway, a landing runway will still be described as existing.
"arresters" are the wires and nets usually called that located on a landing runway and used on vessels to assist CTOL aircraft landing.
"runway" is a take-off runway or a landing runway.
"pad" is a take-off or landing pad on a vessel, this being a level area of open deck and having unobstructed air space around it so that VTOL aircraft can launch and/or land upon it; in this specification, even if such a pad is no more than a section of a runway suitable for the launching and/or landing of VTOL aircraft, a pad will still be described as existing.
"draw-down device" is the device usually called that located on a pad and used on vessels to assist VTOL aircraft landing.
"parking area" is a level area of open deck on a vessel where aircraft can be temporarily parked prior to launching or when their removal from a hangar is required; in this specification, even if such an area is no more than a suitable part of a runway or pad, a parking area will still be described as existing.
"hangar" is the structure usually called that on a vessel, this allowing the accommodation of aircraft; in this specification, even if such a structure is no more than a sheltered area, deck, tunnel or passage into which aircraft can move and in which they can park and be sheltered, it will be described as a hangar.
"lift" is a lift for transporting aircraft between decks, the term here not referring to lifts not for transporting aircraft.
"CTOL" vessel is a vessel with a take-off runway, a landing runway, a catapult, arresters and a pad.
"STOL" vessel is a vessel with a take-off runway, a landing runway, and a pad.
"STOVL" vessel is a vessel with a take-off runway and a pad.
"VTOL" vessel is a vessel which can only deploy VTOL aircraft.
"carrier" is a vessel a prime role of which is operating aircraft.
"other-role" vessel is a vessel that is not a carrier.
|Join the GlobalSecurity.org mailing list|