4.5-inch H.E.-A.R. T83 and Practice T87

Over-all length, inches

Total weight, pounds

Head lenght, inches

Weight of charge, pounds

Range, yards

Fuzing

Mk 149

General: This is one of the "fixed-fin" type of 4.5-inch rockets, the other being the S.A.P. round. It is a high-velocity rocket, fired from the zero-light launchers.

Head: The high-explosive head T2002 is thin-walled and has an adapter and fuze-seat liner for the Nose Fuze Mk 149. An Auxiliary Booster Mk 3 Mod 1 is shipped in the fuze seat, protected by a chipboard disc and a shipping plug.

Motor: The T2000 motor is connected to the head by a steel coupling, threaded in-ternally. The motor tube is constricted at the rear to form the nozzle. Lug bands are one button-type band and one zero-length band, 45.53 inches and 10.25 inches respectively from the base of the rocket.

Tail: The T2000 tail assembly - four flat fins mounted radially on a metal sleeve - is secured to the nozzle by a threaded retainer coupling.

Propellant: Twelve single-perforated sticks of powder having 7/16 inches inside dia-meter and 1.22 inches outside diameter, 20.6 inches long, are mounted in two banks of six each on the bars of a cage-like support.

Igniter: An electric squib and 2-¾ ounces of black powder are assembled in a plastic tube 6-¾ inches long and one inch in diameter. This tube is suspended from the end of the propellant in the center of the tube. The ignition wires pass to the rear through a plastic closing cap cemented in the throat of the nozzle. They terminate in a phone-type plug. About two feet of igniter cable are held in the flare of the nozzle by a fiber cap ce-mented in place.

Practice round: The T87 - T2003 head and T2000 motor - is like the T83 except for the live fuze and explosives, for which inert substitutes are provided.

Figure 121. 4.5-inch A.R. - H.E. T83 (above) and S.A.P. T78 (below)