Description
The rocket motor is a solid-propellant thrust unit used primarily for launching target planes from a catapult, although it may be used for other applications requiring a unit of the same characteristics.
The JATO M3A2 rocket motor consists of the following:
Body assembly. The body assembly is a cylindrical steel tube closed at the forward end by the head and threaded externally at the open rear end to receive the nozzle.
Nozzle. The nozzle, which is of steel, is of the convergent-divergent type comprising a conical rear portion and cylindrical forward portion. The cylindrical forward end of the nozzle is threaded internally to engage the rear of the body assembly.
Igniter plug assembly. The igniter assembly consists of a “shorted” igniter plug and a nozzle closure which are connected by two lengths of igniter cable. The nozzle closure is a plastic, cup-shaped disk into which two copper terminal inserts are molded. The closure is cemented permanently into the expansion cone. The igniter plug is a standard, two-pronged, rubber-bodied electric plug which is short circuited by a copper wire tied across its prongs. The two cables from the plug are crimped into the terminal inserts in the nozzle closure.
Igniter assembly. The igniter assembly is designated “Igniter, JATO, M21.” It consists of a plastic igniter case containing a 463-grain charge of black powder, two squibs, each of 1.0 ohm resistance, and two 24-in. long external lead wires which are connected to the squibs. Electric terminals for the squibs and lead wires are riveted to the plastic wall of the igniter case. The lead wires pass through the center of the JATO and are crimped into the copper terminal inserts in the nozzle closure.
Propelling charge. The propelling charge consists of seven mono perforate cylindrical extruded grains of double-base propellant M16 (T6). The grains are arranged in the JATO lengthwise with one grain in the center and six grains surrounding it.
Rear trap assembly. The rear trap assembly is a star-shaped steel casting with six equally spaced radial arms and a hexagonal center hole. Six cylindrical trap rods, one each from each radial arm, extend axially toward the forward end of the JATO to form a cage like support which receives six of the seven propellant grains.
Front trap assembly. The front trap assembly is a wheel-shaped steel casting comprising an outer ring, center hub, and three radial spokes. A cylindrical trap rod extends from the center of the hub axially toward the rear of the JATO. This rod receives the seventh (center) grain of the propelling charge.
Functioning
No information about functioning.
Hazardous Components
No information about hazardous components.
See Also
Nothing else to see.
Source(s)
TM 43-0001-30, Rockets (chg 14, 2001)
