NITROGEN CONTROLVALVE.- The nitrogen control valve is a solenoid-operated shutoff valve that controls the flow of nitrogen from the receiver assembly to the missile. Operation of the control valve is controlled from the cockpit by the pilot.

Power Supply

One power supply is available for use in the launcher. Power supply PP-2581/A is a single-phase power supply. It is a self-contained unit with connectors on each end. The aft connector links the power supply and the mechanism assembly. The forward connector provides the connection to the missile's umbilical cable.

Forward Fairing Assembly

The forward fairing assembly is an aluminum casting that mounts to the forward end of the outer housing to provide an aerodynamic nose to the front of the launcher. It has two doors that are spring-loaded to open. These doors provide access to the umbilical hook support assembly.

Umbilical Hook Support Assembly

The umbilical hook support assembly mounts to the forward housing rails and, during missile loading, is connected to the missile umbilical shear block. At missile launch, the mechanism snaps up, retracting the sheared end of the umbilical cable into the launcher to prevent interference with the missile hangers.

Fin Retainer Assemblies

Two fin retainer assemblies are mounted to the forward end of the housing assembly beneath the forward fairing assembly. The fin retainer is a small, U-shaped bracket that contains two spring retainers that

Figure 3-19.-Mechanism assembly detent and snubbers. 3-24

Figure 3-20.-Aft snubber mount fitting assembly, aft fairing assembly, and aft fairway latch assembly.

snap over the missile fins to prevent movement during captive flight.

Snubber Mount Fitting Assembly, Aft Fairing Latch Assembly, and Aft Fairing Assembly

The aft snubber mount fitting assembly, aft snubber assembly, and aft fairing latch (fig. 3-20) are assembled together as a group and mounted to the aft end of the housing assembly. When the aft fairing latch assembly (fig. 3-21) is in the open position you can access the nitrogen receiver. It also releases the aft snubbers to allow missile loading. When in the closed position, it allows the snubbers to spring over the aft missile hanger, locking it in place.

For further information on the LAU-7/A (series) guided missile launcher, refer to Guided Missile Launcher LAU-7/A, NAVAIR 11-75A-54.

Figure 3-21.-Aft fairing latch assembly.

Figure 3-22.-LAU-115A/A, LAU-115B/A, and LAU-115C/A guided missile launchers.

Table 3.3.-LAU-115 Technical Characteristics

LAU-115 SERIES GUIDED MISSILE LAUNCHER

The LAU-115 series guided missile launcher (fig. 3-22) is a reusable launcher. It completes the F/A-18 aircraft suspension and launching system for the AIM-7 Sparrow missile. The technical characteristics can be found in table 3-3. The forward internal grooves of the rail provide a guide and support for the forward missile mounting button. The external rail flanges are a guide for the aft missile suspension lugs during firing. The aft section of the rail consists of a removable fitting that provides mounting for the aft missile suspension lugs.

The latch mechanism is composed of a detent cam and keeper. The detent cam is spring-loaded down and acts as a stop during missile loading. The cam mechanism is constructed so the force created by the missile motor during normal missile firing overcomes the detent cam spring tension. This action lets the missile button push the detent cam up, actuating the missile-gone switch.

An electrically operated solenoid is used to assure that the missile is retained during sudden deceleration, such as an arrested landing. The keeper portion of the latch mechanism is spring-loaded to the down position and retains the missile during all periods of aircraft acceleration. The keeper mechanism has an indicator. When the keeper is in the down or latched position, the indicator is flush with the launcher skin. If, during missile loading, the missile button is not in its maximum forward position, the indicator extends beyond the upper launcher mold line. This indicates that the missile is not properly latched in place. During loading, the missile button can slide past the keeper, stopping when contact is made with the detent cam.

During the unloading of a missile, the indicator bell crank is supported in the launcher structure. It is manually operated by using a 3/8-inch square drive tool. The square drive end of the bell crank is accessible from the side of the launcher. The launchers are suspended from BRU-32 bomb racks in the outboard pylons. Two LAU-7/A launchers can be attached for suspension of the AIM-9 missiles. For ground safety, an actuator-operated safety device prevents inadvertent loss of the AIM-7 missile.