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Otomat is a weapon in the same mold as the McDonnell Douglas Harpoon, these being the West’s only advanced air-breathing antiship missiles—dis
counting the Swedish RB08A —in service or about to become operational. Development began in 1969 when the Italian company OTOMelara and France’s Matra (hence the missile’s name) decided to collaborate; the Italian concern had been working since 1967 on a weapon to counter “Styx”-armed “Osa” and “Komar” missile boats in the Mediterranean, and Matra had been carrying out similar studies as a private venture.
The first prototype unguided round was flown in 1971, and successful guided firings began the following year. Development of this Mk 1 version, which uses a two-axis seeker (scanning both horizontally and vertically) to allow terminal maneuvering, has now been completed. The Mk 2, with a single-axis, horizon- scan homing head, was first tested in January 1974 and is known as Teseo by the Italian Navy. Italy has ordered
Otomat to arm four new Lupo-class frigates, four Sparviero-class hydrofoils, and the planned patrol missile hydrofoils (PHMs). Peru, Venezuela, and Libya have also ordered the weapon, which is additionally being offered to Egypt to replace “Styx” on “Osa” vessels.
The 17-foot-long, 1,600-lb. missile is fired from a fixed glass-fiber launcher/ container canted up by 15° and offset between 10° and 20° from the ship’s fore-and-aft axis. The launchers/con- tainers are sealed in the factory and remain closed apart from overhaul, which occurs after firing or one year. Periodic checks are carried out on board ship.
Targets are acquired optically or by radar; the enemy ship’s position, course, and speed are fed to a plan-position indicator (PPI) console in the operations room. Information then passes to a missile guidance computer and launch sequencer, coupled with a data extractor which handles inputs from the ship’s log, anemometer, gyro-compass, and true-vertical sensor.
The computer feeds the missile with an instruction to turn left or right after launch, a heading on which to roll out after its constant-acceleration turn, and a time at which to activate the seeker head. Reaction time from target acquisition by the search radar to missile launch is less than 30 seconds. There is no need for the ship to turn toward her target, because Otomat can be maneuvered through 300° in azimuth after launch.
The launch and mid-course phases are the same for both the Mk 1 and Mk 2 variants. Two solid-propellant boosters mounted on either side of the center body accelerate the missile off its launch rail; they burn for about four seconds and are blown off by explosive bolts, cruise propulsion being taken over by a 1,935-lb. thrust Turbome'ca TR281 turbojet developed from the Turmo III used in Aerospatiale’s Super Frelon helicopter.
If the weapon is fired against a target at normal range (25 nautical miles) the after-launch climb levels out at 265 feet and then descends to the cruise height of 65 feet. For short-range flights (down to a minimum of 3.25 nautical miles), however, the missile reaches altitudes as much as 575 feet.
Guidance during cruise is pseudoinertial, using a gyro-stabilized platform
and radio altimeter. The procedure employed during the attack phase depends on whether the missile is a Mk 1 or a Mk 2. The former has a Thomson- CSF two-axis seeker and the latter an SMA (Societa Marittimo ed Aero) single-axis homing head. When a Mk 1 Otomat has flown for a preset time, calculated before launch by the parent vessel’s computer to position the missile 6.5 nautical miles from the target, the active-homing head switches on and scans 20° on either side of the nose. Once the seeker has acquired the target it locks on and corrects the missile’s heading. At 2.25 nautical miles from the target, as measured by the homing head, Otomat climbs to 575 feet, reaching its apogee one natutical mile from impact. It then dives to the target at an angle of 7 ° below horizontal.
If the homing-head emissions are being jammed, so that accurate ranging is impossible, the missile enters a climb (again to 575 feet) at 3.8 nautical miles from the target (computed from elapsed time) and descends in a slightly flatter dive at 5°. A Mk 2 Otomat, however, descends directly from its 6 5-foot cruise altitude to sea-skimming height for the attack and does not carry out the terminal maneuvers which were designed to allow a ship’s lightly armored upperworks to be penetrated but which make the weapon vulnerable to point defenses.
The missile’s semi-armor-piercing warhead contains 145 pounds of high explosive and is designed to penetrate 1.6 inches of nickel-chrome armor plate. Total warhead mass is 460 pounds, to which must be added any unburnt kerosene. Destructive payload therefore adds up to some 550 pounds.
A single Otomat has an effective range of 32.5 nautical miles. At that range the target is certain to fall within the area scanned by the missile’s homing head. By firing a salvo of two missiles, on slightly divergent courses but with overlapping seeker coverage, the effective range is increased to 43.5 nautical miles. The missile carries sufficient fuel for a flight of 110 nautical miles, and the Mk 2 version has provision for midcourse guidance updating to allow the full range to be used. Air-launched developments of Otomat have been proposed but plans for them have now been’abandoned.