Upon selection of a Standard or Harpoon missile in the magazine, the weapon is hoisted onto the single guide arm. Harpoon missiles receive initial warmup on the guide arm. (Standard missiles do not require warmup.)
The launcher trains and elevates in response to order signals from WCS to aim the missile toward the predicted target. When the launcher synchronizes within 10 either side of the ordered position and the missile is ready internally, WCS may initiate firing. After the missile fires, the launcher automatically returns to the LOAD position to receive the next missile selected for loading from the magazine.
During continuous launching operations, the system is capable, under ideal conditions, of a successive firing rate of (1) Standard missiles at 10-second intervals and (2) Harpoon missiles at about 22-second intervals. This action continues until a cease-fire order is given or the missile capacity (excluding the GMTR) of the magazine is exhausted.
A launcher control station contains controls and indicators to regulate and monitor launching system operations. Under normal operating conditions, the Mk 13 GMLS requires the services of a launcher captain and a safety observer. The launcher captain supervises the overall operation of the system and performs all functions at the EP1 and EP2 panels as directed by WCS. The safety observer watches the launcher area and warns the launcher captain of unsafe conditions.
The Mk 13 GMLS consists of three major component areas, which are the launcher, the magazine, and the launching system control. We will discuss the launcher first, then the magazine. Again, watch the terminology.
The launcher (fig. 7-4) is a self-powered major assembly that supports, aims, and prepares the missile for firing. Part of the launcher is on top of the stand, while the rest of it sits within the magazine structure. The main components of the launcher are the guide, the carriage, and the train and elevation power drives.
The single arm launcher guide is mounted between the left- and right-hand trunnion supports and consists of the guide arm structure and a yoke. The guide arm holds and prepares the missile for firing. The yoke is an extension of the guide structure, or weldment. It pivots on trunnions extending from the left- and right-hand trunnion supports. The yoke also provides a weatherproof housing for some guide components and serves as a passage for electrical cables and fluid lines.
Figure 7-4.-Mk 13 Mod 4 GMLS, launcher.
FIXED GUIDE RAIL.- The fixed rail (fig. 7-5) is slightly less than 30 inches long and is secured to the lower or aft end of the guide arm structure. In addition to forward and aft shoe tracks, it contains an internal track for the hoist chain, the pawl, and the rollers. A cam track engages a special pair of rollers on the chain to compensate for any hoist chain overtravel as it extends up to the launcher. This is called the adjustable buckling chain link and is shown in figure 7-12. The cam track directs any excess chain into an upward curving chamber midway within the fixed rail.
An actuator arm in the forward left section of the fixed rail is a safety device. Through mechanical and hydraulic interlocks, it prevents the aft-motion latch from prematurely retracting during an unload cycle until the hoist pawl properly engages the aft missile shoe.
LAUNCHER RETRACTABLE RAIL.- The launcher retractable rail is an 8-foot-long unit that pivots between two positions. It remains extended except when the fired missile goes into free flight and during a jettison operation. During missile firing, it guides the missile for the first 20 inches of travel and then retracts so the aft shoe and fins do not strike it. For jettisoning a missile, the rail must be in the retracted position to engage the jettison mechanism.
A pivot unit connects the aft end of the retractable rail to the guide arm structure. The two retract shafts at the forward end of the retractable rail extend or retract the rail by means of the rail operating piston and control valve block. Latches secure the rail in the extended or retracted position. A cable within the right-hand shaft contains leads for the rocket motor igniters. The left-hand shaft contains some of the components of the rail retract trigger.
The rail retract trigger is a pivoting bar that protrudes through a slot at the forward end of the retractable rail. When contacted by the forward shoe of the fired missile moving forward, the trigger initiates the mechanical and hydraulic actions that retract the rail.
The arming tool is located between the rocket motor igniters. It mechanically opens and closes the circuitry between the missile firing contacts and the ignition squibs of the rocket motor. The tool is a cylindrical piece that contacts the arming lever of the missile. It is actuated by a spring-loaded rod and linkage mechanism attached to the latch lock of the forward-motion latch. Disengaging the latch lock arms the rocket motor.